Canning 101: Tomato Float, Sauce Separation and Loss of Liquid

August 24, 2011(updated on October 3, 2018)

122 | 365

Tomato canning season is here and so I’ve been getting a lot of questions from people who are canning their own tomatoes for the first time. They worry because their tomatoes are floating, their crushed tomatoes have separated or their jars have lost significant liquid in the canning process and now they’re not sure if their tomatoes are safe. Let’s take these three topics one by one and put your hearts at ease, shall we?

Tomato Float
Take a look at the jars on the left in the picture above. Those are the whole, peeled tomatoes that I canned last year. As you can see, the tomatoes are floating over a good inch of liquid and tomato sediment at the bottom of the jar. This one is absolutely no big deal.

Even the most seasoned canner is going to have some canned whole tomatoes that float. This is because there are air pockets inside those tomatoes and when you pack something with some internal trapped air in a liquid, it will float.

You can try to avoid float by using regular mouth jars (the shoulders of the jar help keep the fruit in place) and packing the jar as firmly as possible (without totally crushing the tomatoes). But really and truly, it’s no big deal.

Tomato Separation
Often, I will hear from people who are concerned because their crushed tomatoes have separated into a layer of liquid topped by a layer of solids. What happened here is that you heated your tomatoes for more than five minutes, let them cool and then heated them up again.

By doing this, you’ve broken down the pectin inside the tomatoes. In this situation, the pectin was there holding the structure of the cells together and once it goes, there’s nothing to maintain the integrity of the tomato flesh together and so pulp separates from the water.

I never worry about this one either. Just give the jar a good shake before using.

Liquid Loss
Back to the picture up at the top. Take a look at the quart jars on the right. You might notice that several of those jars lost a TON of liquid. I canned that particular batch in my pressure canner and during the cooling process, they siphoned like mad (that’s the official canning term for when liquid escapes).

Siphoning can be prevented by better bubbling of jars and a slower cooling process. However, even when you’re careful, it still happens sometimes. However, as long as your seals are good, jars with even significant liquid loss are still safe to eat.

You may experience some reduction of quality over time and when it happens to lighter colored foods (like peaches), the product that’s not submerged will begin to discolor. Put those jars at the front of the queue of jars to use and don’t worry about it.

Air Bubbles
Sometimes, you’ll preserve tomatoes and once the jars are sealed, you’ll notice that there are a few air pockets or bubbles in the finished product. As long as the lids remain sealed and those bubbles aren’t actively moving around on their own, the jars are fine. Once a jar is sealed, air pockets are only a problem if they seem to bubbling independently of you moving or tapping the jars, as that can be a sign of fermentation. Otherwise, all is well.

What other tomato questions do you guys have? Let’s hear it!

Sharing is caring!

Posted in

Leave a Reply

Your email address will not be published. Required fields are marked *

537 thoughts on "Canning 101: Tomato Float, Sauce Separation and Loss of Liquid"

  • Thank you so much! This was my very first time canning, and I had what you described as tomato separation. I was completely depressed, since these were garden tomatoes and I thought I’d completely botched it.

    I think my problem is that I had already lightly pureed them, and then I cooked them for 5 minutes and THEN had the water bath. Sounds like I shouldn’t have pureed them, but kept in chunks. I might have also had too high a boil.

    I’m simmering down now…thanks again…

  • I water-bath canned tomato sauce yesterday, and when finished, one of the jars had lots of bubbles at the top. The lid sealed, but I’m wondering where all the bubbles are coming from? When I did tomato sauce last week, none of the jars had any bubbles. I’d guess that I didn’t get all the air pockets out?

    1. Hi Jenny

      your question about the air bubbles in the tomato sauce is from 2013. but did you ever get an answer. we have air bubbles in our tomatoi sauce. lids are sealed, the bubbles don’t move unless a person shakes the jar.

      1. Bubbles aren’t a big deal unless they are actively moving on their own. The bubbles that only move when you shake the jar aren’t a problem at all.

  • I just pressure canned a batch of tomato pasta sauce. I let the jars cool in the canner for quite a while after the pressure was released but when I opened the lid, there was tomato pulp on the sides of the canner and in the water. Only one of the jars sealed. The rest now have lots of airspace and look like paste instead of sauce. What did I do wrong? I processed @ 11 lbs pressure for 25 min as the directions on my canner told me.

    1. It could be that you didn’t wipe the rims sufficiently. Or that you didn’t let the pot rest long enough (I tend to let mine sit overnight before opening). Or that the lids were old. Or that you didn’t remove the bubbles from inside the jars well enough. You also have to tighten the rings just a little bit more when you pressure can than you do when you can in a boiling water bath canner.

  • Canned a batch of tomatoes and didn’t hear a pop. Don’t know if they sealed. Also when I put them up in my pantry I noticed the lids weren’t screwed on tightly. Do you think this batch is lost?

    1. Just because you don’t hear a pop doesn’t mean that your jars didn’t seal. Press the lids. If they’re firm and do not wiggle, they are sealed. The rings don’t need to be tight for the jars to be sealed.

  • HELP! There must be a easier way to make saulsa. I blanced the tomatoes, peeled them then took out the seeds and I had a mess. I used a lot of tomatoes to get just 3 pints of saulsa.

    1. Hi Vicky…Salsa is very labor intensive for sure! But it is so worth it come winter. My family really loves it! What I have found out is that I do the hard stuff first. That (for me) is chopping all the “hard” ingredients. I usually do those in the morning, then stick it all in a freezer bag and put them in the fridge. If I get busy with something else, I don’t have to worry about them getting too soggy. They are going to cook down anyway. I have even did that and then finished the next day. I have also had great luck with putting the tomatoes in a blender for a spin or two, then dumping that into my pot. Do that for about half of the tomatoes. This will cut the time a little. The trade off is that your salsa will not be really “chunky”. Add the remaining “chopped” tomatoes to the pot along with the rest of the ingredients and process it like you normally would. Canned salsa is normally not like the “fresh” chunky salsa that all of us love in the summer. I use the Ball blue book recipe and play around with the peppers. I haven’t had one complaint yet and many family and friends ask for it a lot. I will also admit, because it is so labor intensive to make, I rarely “give” jars away…:-) Good luck and try it again!

      1. Will blending the whole salsa make a difference? I am going for super traditional Mexican salsa, which, in my case is usually made with boiled tomatoes and chiles, which are pureed with the rest of the ingredients. In other words i want a thin salsa. Not chunks. If i follow the recommended recipes can i puree all the ingredients before simmering on the stove?

    2. I am in a similar boat… My pressure cooker wouldn’t come up to pressure so I had to abort the canning process. By this time it was almost midnight and I didn’t have time to reprocess immediately. Everything I’ve read says to reprocess within 24 hours, but do I need to refrigerate the cans? Do they then need to come up to room temp before starting again? I was canning raw pack tomatoes no added juice or water…

  • Hello, I canned a few jars of tomatoes the other day but 4 of my 6 jars didn’t seal after processing. I didn’t have any time to process them again so I put them in the fridge. I had another set of unprocessed canned tomatoes too that I did not immediately process. I covered them with the lids, put them in the fridge. Now it’s been 3 days since I initially canned the tomatoes. Can I still process them now? The ones that I processed that didn’t seal have now seemed to ferment a little bit as when I opened one of the jars air and juice came hissing out. Did I waste all these tomatoes??
    Thank you for your help!!

  • Hi: I’m am canning for the first time and I don’t have a pot of water big enough to submerge my cans when heating them. Is that going to hurt the process?

  • I pressure cooked the first batch of tomatoes and I went against directions and pulled the weight off early to release pressure faster after processing time because I had so many tomatoes to run through and I didn’t want to wait. I got the tomato float and loss of liquid, so that’s my fault. The rest I just waterbathed (I added extra acid to ensure safety) and they turned out beautifully like usual. I was pretty sure that first batch would be ok, but now I am very confident, so thanks for addressing it in your post! Sometimes it’s hard to find specific, direct answers about canning. I prefer waterbath to pressure canning just because it takes so long for the pressure canner to get to pressure and to release pressure at the end, it takes longer than waterbath. I wonder why that is? Maybe my sea level? Not sure.

    1. Pressure canners just take a long time to release their pressure. Mine can take up to an hour. This is why I don’t really recommend pressure canning for tomatoes that, as long as they’re acidified properly, can easily be done in a water bath canner.

  • I can tomatoes every year(water bath) and have never had any trouble. One jar this year became slightly cloudy. It was not immediate. I keep my canned goods in a pantry and notice this jar about 1 or 2 months after processing. Should I throw them out? Thank you for your attention.

  • Thank you so much for this post. I had separation and slight liquid loss. I wasn’t sure if that was a bad thing or not. This was very reassuring.

  • Thank you sooo much for this wonderful post! I have canned with a friend before, but today canning by myself I experienced siphoning for the first time. I had no idea what had happened and felt like a total failure, so sad! I thought they were ruined, and I’d have to reprocess them. I am still a little worried, it’s my nature to be a worry wart, but I’m following your advice on making sure they’re SEALED, and I think everything will be fine. Thanks again!

  • Hello! I know this was an older post, but I need some canning advice. Help! 🙂
    Yesterday I processed about 100 lbs. of tomatoes, some of which I turned into a seasoned paste using my oven to reduce the sauce down. (Thank God, ’cause it took like six hours!!) I followed directions I found on the internet for canning the paste. I used 1/2 pint jars and left a 1/4″ headspace as per the directions, added 1/2 tsp. lemon juice per jar, and processed them in a boiling water bath for 45 min.This morning I went to clean my jars and check the seals, and discovered that paste had leaked out of the better part of my jars-not a ton-the jars are properly full, but it left sticky paste under the rings on the outside. My seals are nice and tight-I triple checked-but now I’m freaking out. Obviously the recipe should have said 1/2″ (I think), but are they safe? And why aren’t there more recipes for canning paste out there?

  • Thanks so much for this post! I made my 1st batch of cold packed tomatoes last night and I had some bubbling out of the jars and now some liquid is below the level of the tomatoes… so I was worried. But not anymore! Ready to take on the rest of the box! Thanks!

  • how long do you need to boil the tomatoes before canning? I have tried canning salsa many times and really didn’t know that you needed to “cook” the salsa before canning so I have not had luck with the salsa staying good. any “basic” canning information would really be helpful! I would love to start canning more! Thank you

  • Thank you, Marisa. I definitely feel better about this batch than I did the first batch. Hopefully, they’ll still taste good after twice having been cooked to death. 🙂

  • Hi. Today, I water bathed whole tomatoes in tomato juice for 85 minutes. I left 1/2″ headspace while using new lids and jars. The jars didn’t seal and some of the tomato juice escaped from the jars and into the pot of boiling water. Can I reprocess these jars or are they contaminated? Should I add more citric acid to safeguard against any citric acid that might have been lost in leakage during the first process? Anything else I should be doing in regard to keeping this batch from going bad, or is it just as easy as wiping rims, heating new lids and reprocessing? Thanks in advance.

    1. Stan, the jars aren’t contaminated, it sounds like either your lids were bad or there was some siphoning of the product that impeded the seal. You can rebubble the jars, apply fresh lids and reprocess.

      1. Thanks, Marisa. Quick question. Today we sanitized new jars by boiling for 10 minutes; boiled and then simmered new lids for 10-plus minutes; packed warm jars with contents from the jars of yesterday’s batch; cleaned rims of jars thoroughly; and then put warm lids on and banded finger tight. We decided to pressure can the jars this time. All seven jars sealed and we heard each lid pop within 10 minutes of removing jars from canner. So all seems good. My only concern as a newbie canner is that the water in the canner has a bit of tomato floaties in it. Is this normal when canning? Does some of the product leak out, and if so do the lids still get a good seal when tomato juice has seaped over the rims of the jars during processing. Again, thanks in advance, Stan

        1. Totally normal. There is always some liquid loss during tomato processing, particularly those done in a pressure canner. Often, little bits of tomato also sneak out during the siphoning. As long as the seals are good, it doesn’t matter.

  • One of my jar of tomatoes has separated and there are tiny air bubbles in the jar. Should I be worried about the air bubbles? Someone else posted this question (number 83), but I didnt see an answer.

    Also…I accidentally used iodized salt instead of pickling salt – what will happen?

    1. Like I said in this post, the separation is normal and comes from when tomatoes are heated, cooled and heated again. The only time you should worry about air bubbles is if they are active and moving, as that can indicate that the product has begun to ferment. However, inactive trapped pockets of air are entirely benign. The iodized salt could cause some discoloration or fogginess, but it won’t cause any true harm.

  • Marisa, Why would I want to do a hot pack with my tomatoes versus a cold pack? Both options are in my Ball book, and the cold pack just seems like one less step. Is there any difference in the finished product? Thank you!

    1. Some people report that they get more tomatoes into the jar and have less tomato float after processing when they do the hot pack. However, I always do the cold pack, because I just want to get the tomatoes peeled and into the jars.

  • Hi! I followed directions for your cold plum tomatoes packed in their own juices. I processed three jars – 1 sealed and 2 didnt. I also did 3 jars of Dilly beans – 2 sealed and 1 didnt. Any thoughts on why some sealed and some did not?? Thanks!

    1. It could be that you didn’t simmer the lids long enough, or that your lids were old, or that there was crud on the rims of the jars, or that you didn’t sufficiently bubble the jars and some product escaped and impeded the seal. There are a number of reason why seals fail.

  • Canning tomatoes is new to me as well this year. I don’t have a good feeling about what I’ve canned so far. I don’t think that there isn’t enough space between the tomatoes and the lid and there are bubbles. I didn’t heat them for five minutes after I removed the skin but I process them in a waterbath for 45 mins. after I filled them and they did seal. I canned them on Thursday and Friday but now I’m afraid to eat them. Is it too late to re-can them tomorrow? The lack of space at the top under the lid and the tomato debris inside around the band are what concerns me. What should I do?

  • Marisa, If I add a citric acid to the next batch & eliminate the olive oil (add it after I open my canned product while heating & immediately prior to eating) I will have resolved the two crucial issues, right?
    Your tip / suggestion is appreciated: What kind of citric acid do you recommend that will not impact taste, and would you please provide the ratio of acid needed to ounces of cooked tomatoes? Thanks Much!

      1. Gigi, red wine isn’t citric acid. And no matter how long you cook it, garlic is still a low acid ingredient. The rule of thumb with citric acid is that you add 1/4 teaspoon for pints of tomatoes and 1/2 teaspoon for quarts. I think you need to read the National Center for Home Food Preservation’s page on canning tomatoes. http://nchfp.uga.edu/how/can3_tomato.html

  • I have just prepared my tomatoes using a very different process & am worried that I certainly did something wrong. I quartered & seeded tomatoes, seasoned them with salt, pepper, oregano, olive oil & then roasted them in the oven. Once roasted & softened, I allowed the tomatoes to cool, removed the skins & pulsed chopped them in a processor. I then added a bit of water to a saucepan with the tomatoes & basil & cooked them down. I sterilized my jars, bands & lids in a hot water bath & then filled the hot jars with the hot sauce. I then placed them back in a hot water bath, allowing to boil for 40 minutes. My BIGGEST concern is that i did not add any citric acid. Should I plan to eat the tomato sauce this weekend b/c it will never last?! Also, I think i may not have left a half inch between the lid & the sauce. I guess I should have did my reading first! How safe is my process? Thanks for this informative site!

    1. Gigi, the two biggest concerns with your tomatoes are the facts that you didn’t add any additional acid and that you added olive oil, which can can also harbor botulism growth.

      1. Wow Marisa. Even though the garlic was slivered and roasted in the oven for about a half hour at 400 & then cooked on the stove top presents botulism as a possibility? Okay, now i am scared. I had heard about raw garlic sitting in olive oil being a problem – but never thought cooked was an issue.

  • thanks for this – I just water-bath canned my first batch of crushed tomatoes and they’re floating – so bummed but now I know that I’m not alone. Thank you!

  • We canned 7 quarts of whole tomatoes. Did the normal steps….boil in water for a minute or less to get the skins off, cut out core and quarted the larger tomatoes, put them in quart jars and crushed them down til there was 1/4 at the top and used 2 tbs of lemon juice in each. We put in the water bath method for 85 minutes and we got the separation solids on top water on bottom. Based on what I read here I’m not concerened about the separation, but what concerns me is the tomatoes floating at the top have seemed to develop air bubbles. We’re not sure if we should be concerened with this. I’m considering turning them upside down once they cool to let the water work its way back into the tomatoes, but would prefer the advise of a seasoned canner to confirm whether or not that would be ok.

  • I just canned 12 quarts of tomatoes. I cold packed them adding 1 teaspoon of salt and 2 Tablespoons of bottled lemon juice. I used my Ball book and it is evidently old because it says to water bath them 45 minutes. Now I see the recommendation is for 80 minutes.

    All the jars sealed fine. Should I water bath them longer? Would I have to break the seal or could I just but them in a bath again? I have some float but they look good.

    Thanks

  • Thanks for the note about the siphoning, I followed your ideas for canning whole tomatoes in their own juice, but obviously let them heat up for more than 5 minutes initially, so I ended up with both separation and the siphoning contained a good deal of tomato matter. The seals appear to be good though (upside down and held by the lid) so I’m going to call them good!

  • Quick question: I decided to make spaghetti sauce really late in the day (bad idea). Now, I’m hoping when it’s done cooking I can put the pan in the fridge and bring to a boil tomorrow before putting in jars & processing. Do you think this would be okay/healthy?

  • I appreciate all the great info here!

    Yesterday, I followed the Ball instructions for canning crushed tomatoes. I used the bubble remover to push out any bubbles and processed as instructed. Now there are still pockets of air throughout every jar. The seal seems fine, but I am worried about these air bubbles!

  • My tomatoes are floating all the way to the top and touching the lid. It did make a good seal but I’m guessing I used too much water. Should I open these and eat right away or will they be ok?

    1. They are fine. It’s not the optimum result, but as long as the seals are good, they are shelf stable and safe to eat.

  • Every recipe I find says to select whole unblemished tomatoes to preserve. My garden has produced lots of tomatoes that look like the one in your tomato post picture. There are brown cracks around the stem. The tomatoes taste great, and I’d like to cut off the brown, dice them, and can them. Is there a reason why all the recipes call for “unblemished” tomatoes? Is there bacteria etc. that could be dangerous?

    Thanks!

    1. Julie, I think that people are concerned about bacteria. However, with the amount of heat exposure that canned tomatoes receive, it’s hard to image that any bacteria survive. What’s more, perfect tomatoes are really hard to come by. I use the slightly cracked ones for preserving on a regular basis and have had no ill effects.

  • My Grandma taught me how to can last summer. She doesn’t put her stewed tomatoes in a water canner. She just boils everything, puts the tomatoes in hot, and lets them seal up on the counter. Is this not an approved method anymore? She’s been doing this for 60 years and has never had a incident. I’ve talked to many others who also do it this way.

  • I just canned 14 jars of tomato sauce (tomato, garlic, onion, chopped carrot, peppers, spices etc)…..did mostly 1 1/2 pint jars w/a few qt jars.

    I processed for 30 mins and everything sealed perfectly. Used hot jars, hot lids, hot contents and then processed.

    This should be fine, shouldn’t it? I don’t understand how our grandmother’s lived through canning the “old fashioned way” (everything hot, then turned the jar upside down until it sealed and then turned upright)….

    Will 30 mins be sufficient?

  • Thank you so much for posting these pictures!

    I started canning in June of this year and I finally got a pressure canner last week. I tried hot packing tomatoes in the pressure canner yesterday thinking the shorter processing time for hot pack tomatoes would be a big time saver. Followed instructions carefully and added lemon juice to be safe. Unfortunately, all 14 quarts of tomatoes siphoned during the pressure cooking process.

    I was up staring at my jars this morning wondering if I had ruined all those beautiful tomatoes. I’m reassured after seeing your photos and reading comments here but I think I will try to can whole / crushed tomatoes in WB and save the pressure cooking for sauces. WB tomatoes definitely look better and did not lose liquid.

  • I water bathed my tomatoes last year and they are still red and beautiful, taste great! This year I obtained a pressure cooker and processed per directions. I did have a great deal of float, but not to worried about this. My question is why is the water bath tomatoes so pretty and red and the pressured ones are orangy looking. Not pretty at all. I haven’t tasted them but they don’t look so good.

    1. The amount of cooking pressure canned tomatoes receive is more intense than those done in a BWB. So they end up looking more cooked.

  • Over the last two weeks, I have made and canned 7 batches (42 qts) of tomato sauce. I did not use an approved recipe… mine was tomatoes, olive oil, salt, and oregano. I cooked for about an hour and processed in hot water bath 45 mins. When I canned my whole tomatoes, I added bolttled lemon juice, but did not to the sauce. After reading that I should have pressure canned, I am very concerned. Would it be safe to re-cook the sauce (boiling for at least 10 mins) and reprocess in a pressure canner, or should I do the boiling at the time I use it? Thanks

  • I am new to canning and did my first batch of tomatoes today. I accidentally read wrong and put 1 tsp of citric acid instead of 1/2 tsp in the jar. 🙁 Do you think this will affect anything? Totally using lemon juice for the next batch!

  • I water bathed my tomatoes last year and they are still red and beautiful, taste great! This year I obtained a pressure cooker and processed per directions. I did have a great deal of float, but not to worried about this. My question is why is the water bath tomatoes so pretty and red and the pressured ones are orangy looking. Not pretty at all. I haven’t tasted them but they don’t look so good.

  • I had gotten as far as pureeing tomatoes and had to put them in the refrigerator, could not return home for 3 days – can I still use those tomatoes for canning? Should I just toss them and start over? Thanks a bunch. (First year with a garden, new to canning)

    1. Susan, if you bring them back up to a boil, you can still can them. Just know that the tomato fiber may separate from the liquid. It’s find, it’s just that the look of it sometimes throws people.

  • I hope you can help. I canned tomatoes in the summer for the first time. I cold packed, peeled, crushed tomatoes in pint jars with a tbsp of vinegar and processed for 45 minutes. None of the seals have broken but all of them have white sediment on the top surface of the tomatoes and/or bottom of the jars. They separated like yours did. They smell fine and look fine. Stored properly. It’s not clearly mold but I can’t tell if this is normal – I’d hate to throw them out.

    I hope you have the time to reply. Thanks for your time.

    1. Erin, did you pack them in water? If you have hard water, it could be that the mineral solids are separating out from the liquid.

  • That photo is perfect – I was able to see the “issue” I am having with my raw packed tomatoes – and I see that the dunking process of peeling is more than likely the cause.

    Hubby introduced me to canning tomatoes over 20 yrs ago but this year he has left me on my own – and I wanted to make sure he wasn’t about to have a ‘gotcha’ moment on me!

    Thanks so much for a nice clear photo 😀

  • I would like to poach my sweet 100’s in olive oil. I can find recipes for this, however, i want to then can them in that olive oil following. I cant seem to find any recipes for doing this. Can you help?

  • I canned 8 quarts of crushed tomatoes last weekend and they siphoned, though not too much. However, when I went to take the rings off I noticed there was some tomato goop underneath the ring and between some of the lids and jars… all the lids are sealed as tight as can be – but are they safe to eat?

  • I am so frustrated. I am new to canning and am all excited about it as I come from a family of canners. I did my tomatoes this weekend and had the problem of them floating to the top and seperating(after reading your blog i know what i did wrong and am glad they will be ok) and some even bubbled out of jar and tomato was stuck under some of the lids. Even though it sealed i chose to open them and make spaghetti sauce out of them to be safe. The thing i am frustrated by is every place I look for processing times it is different. My book says 45 min for hot pack in a water canner, my sisters is 2 editions before mine and says 15 min but she does 35 min.My mom used to do 25 min. I was looking on other sites and one said 80 min and another said 50 min. I just dont understand why there is such a huge difference and how are we suppose to know which ones to go with? Also can you safely add onions and garlic and make a spaghetti sauce and process in a water canner? one site said yes and one said no you would have to use a pressure cooker because veggies are low acid.Thank you

    1. The shorter times are old instructions. Newer research calls for the longer times. And if you’re adding onion and garlic, you need to be following a tested recipe if you’re going to can in a boiling water bath canner.

  • thank you! I just experienced the pectin problem, and so many sources tell you what happened and how to avoid it (duly noted), but not whether or not this batch is ok to use. I’ll shake them up and use ’em! thank you!!

  • Is it okay to use 8 oz jars for plain crushed or diced tomatoes? Most recipes I use in cooking call for less than a pint and I don’t know how much would go to waste if I opened up pint jars in these cases.

  • I’ve never seen anyone explain this, and I’m finding my canning to be a very difficult, discouraging experience.

    I had a bunch of tomatoes yesterday. Peeled and cooked to hot-pack.
    I had my hot jars all ready, and found that it filled 7 pints just fine. That’s all my hot water bath canner would hold. Since that was going to take a Looong time to process, I had no idea what to do with the rest of the tomatos still in the pot. I didn’t know if it was safe to ladle it into jars and just wait till the first batch was done. Or just have to freeze all of that.
    I just put it back in the fridge. Is it now safe to re-heat added to the next batch of cooked tomatoes and start over. I don’t want to cook them over and over, but I don’t know how long I can leave it out, or how long I can leave a full jar before I process it in a bath. I’ve found everything about canning to be exhausting and fearfilled so far, I’m afraid. I have a bunch of jars of lovely tomatoes that I’m now scared to eat for one reason or another.
    I have this same frustration/fear with my jellies. If I’m going to put up food, by god, I don’t want to do 7 jars a day and that’s it.
    Thanks so much for your help!

    1. It’s totally safe to just let it sit out until you’re ready to pack the next round of jars. Just bring it back to a boil before filling the jars.

      Don’t be scared of your tomatoes. As long as you’ve properly acidified them, they should be just fine.

  • Very informative post, thank you so much. Could you address two questions for me when you have the time?
    1. My small-batch canning kettle is aluminum. Should that pose a problem for my tomatoes? The water bath must have trace aluminum in it, and so must the jars since I boil them in there before I drain and fill them.
    2. A couple of years ago I used citric acid while canning tomatoes, and they ended up tasting pretty harsh. Does adding sugar to the jar really balance the flavor? Would I be taking my family’s lives into my hands if I added a leetle bit less than the full measure?
    Many thanks!

    1. It’s okay to use an aluminum pot as your canner, so long as you’re not cooking the tomatoes in it.

      I’ve not used citric acid in my own tomatoes, so I can’t speak to ways to balance its flavor. I tend to stick with bottled lemon juice for my own acidification needs.

  • While working on a patch of tomato sauce in my pressure caner, I realized that the previous batch was processed for 10 minutes, not the required 15. Do I toss that batch or just use it first.

  • Thanks so much for posting pictures with this blog post! I did my first tomatoes yesterday. I lost liquid and the tomatoes are floating. So, I’m not worried about that.

    What my question is though, the tomatoes are floating pretty high and I think they are touching the lid, which concerns me because of the BPA in the lids, which is the whole reason I wanted to do my own in the first place….
    Is there anything I can do about this? Or, should I re-process them with a tighter pack?

    Thanks so much!

    1. Oops, I just removed the jar rings and the tomatoes are not touching the top and the seal is great! So please disregard! Thanks so much!

  • Can you please expand on “slower cooling process”?

    Though my siphoning experience is minimal, I’d like to imprint the correct process. Anything I should add or change to the steps?
    -Tighten rings till they just begin to have resistance, then add a quarter turn.
    Leave the jars in the water 5 minutes after processing time and move to a towel to cool out of drafts.

    This is my first year of canning and am loving it. Due so much to the information you provide on this site with all the facts needed in an easy to understand dialog and good photos. Thanks so much! Glad to have found you.

  • Hey Lovely-
    Miss Rosie goes through a *ton* of ketchup, so this year I though I’d do my own to cut her sugar intake, as the sugar-free stuff in the store is pricey. The Ball recipe has a cup for 4 pints, can I cut the sugar safely? If not, do you have a low or no sugar ketchup recipe? Thanks!!

  • The other day I pressure canned beef stew for the first time. I brought the water to a boil, added the jars, and made sure there was water over the jars like the water bath method. Later I realized that I had too much water in the canner. I had processed under pressure for the recommedned time, but with too much water and siphoning, are they safe?

    1. If you got to the right pressure and processed for the right amount of time AFTER coming up to pressure and the jars are tightly sealed, they should be safe. However, I’ll bet it took forever to get up to pressure, so it might be a tad overcooked. It’ll probably taste okay but your veggies might be a little mushier.

      A little about the science… Pressure canning raises the boiling point of water from 212 to around 240 degrees. That’s the temperature at which the low-acid nasties (namely, botulism spores) die. Normally, you just need enough water to create steam, which creates pressure, which raises the boiling point of the liquid part of the food itself to 240. Since you used a mostly full pot of water, you had to get the food AND all that the water up to 240.

  • I just looked at a web site that said it was never save to store pickled garlic. It said that I need to freeze it, or refrigerate it after hot water or pressure canning. Other sites, and my Ball book, say to store it in a cool dark place.

    I can switch gears and put it in the food dehydrator, but I really want to try pickled garlic. How can I make “Killer” garlic without it becoming “Killer” garlic?

    1. I’m not Marisa but…you can’t can plain garlic put you can safely can pickled garlic. You can’t go wrong following the Ball book.

  • I’m canning Pickled Garlic for the first time ( I harvested 35 pounds and need to do something with it). My Ball Canning book calls for dried oregano. Can I substitute fresh rosemary and/or fresh Bay leaf?

  • Thank you! I canned tomatoes for the first time two weeks ago and all four jars are floaters. I’m glad it’s normal and not a big deal.

    Also, it took a lot more tomatoes than I expected it would. I have to go back and buy another case or two of tomatoes. 🙂

  • Thanks! I’ve never canned tomatoes before, but I can tell you that all of those things would bother me if I hadn’t read this article. Sometimes it’s nice to know when not to freak out.

  • i put up 6 quarts of tomatoes today and since they were heirloom types i didn’t peel or core them…husband was having fits! now i have proof that they aren’t ruined…:) it seems such a bother to peel them and i just didn’t want to

  • My Ball canning book said to put 1/2 tsp of citric acid into each quart. I found citric acid in a brewing store. Is this the same as the stuff I should use during canning?

  • Perfect timing for me, too. I just started canning this year and have had no issues with multiple batches of jam, but I tried salsa (4 pints), and only one sealed. All of them siphoned and separated. I think I’m just going to freeze the other three and use it in cooking later rather than just with chips.

    I honestly don’t know what went so terribly wrong– I bubbled and wiped the rims well. I know that one jar fell over during processing, so perhaps that was part of it, but I’m still miffed at the other two. Could my rings have been too loose? They were fingertip tight, just like my jam.

  • Last Sunday I put up a bunch of tomatoes, however, some did not seal. They have been in my fridge ever since.
    Is it possible to reprocess them?
    I won’t be able to get to then until this weekend (I am sick). Do you think they’ll turn out OK? I was planning to have them come to room temp before I put them in newly cleaned/sanitized jars, then proceeding as usual.

  • I’ve heard of people preparing crushed tomatoes for water-bath canning using a food mill in a way that requires no peeling or seeding… I’m very interested in this! Any advice? Do I cook the tomatoes first? I’ve only canned whole tomatoes before… any processing differences when they’re crushed? Thanks!

  • This actually answers some of the questions I’ve had this week as I’ve been canning whole tomatoes. I have canned them several times before, but sometimes things turn out a little differently as you mentioned. Thanks for the info, very helpful!

  • Opinions on peeling/seeding? I see that nearly all recipes call for tomatoes to be seeded and/or peeled, but I’m wondering if there is any downside to leaving it all in and then pureeing with an immersion blender, or something like that?

  • Thank you so much for this post. I am teaching myself to can ,Have a a few problems, and no one to talk to about them . Where are all the recipes for everything on the table? It is hard to know which recipes are tried and true. I am in Florida and my area doesn’t have a place to go to when in doubt. So I go to the internet. I only wish that there was a site that covers all canning need as you did in this post. And when you have a question there’s a button to post a question. I’ve done carrots and they turned out to mushy. I’am in Florida and sometimes I think the processing time or the pressure cooking is too much because the stuff seems to be over cooked. My manual said go by recipe. Its confusing . Thank you so much for your time and effort in this site.

  • I’m SO GLAD you posted this particular post today because I canned a whole bunch of crushed tomatoes the other day–in the pressure canner–with tattler lids as you have, and ended-up with over 2 inches of headspace after siphoning (again, just like your photo). I knew they’d still be safe to eat as long as they were sealed, but I was afraid the exposed tomatoes at the top would end-up getting mushy and/or brown.

    Against my better judgment, I opened them all, added hot liquid, cleaned the rims and lids, re-warmed the jars, and re-processed. About half the jars worked correctly this time but 2 or 3 siphoned heavily AGAIN and one didn’t re-seal (and it’s now sitting in the fridge…guess it’s getting used for Friday’s pizza night).

    I’m starting to think it’s the tattler lids with their “loosen the band 1/4 turn” rule. I’m curious what your thoughts are. I’ve been using them for soups for awhile now and have had off and on problems with siphoning–particularly with densely packed soups like bean or lentil soup.

    I’m almost tempted to tighten them “finger tight” the next time I use them and hope for a good seal as an experiment.

    Thoughts??

    1. This is from Patrice Lewis’ Rural Revolution Blog when she first used her Tattler lids. She was making refried beans. Please note that the maker of Tattler lids says 1/4 INCH not 1/4 TURN. Big difference. Also the suggestion to try finger tight.
      “Within half an hour, I had a reply from Brad Stieg at Tattler. “Try applying the metal bands finger tight and DON’T reverse them before processing,” he wrote. (If you remember, when using Tattler lids the rings need to be loosened a quarter-inch before processing.) “The metal bands need to be finger tight/snug, but not so tight as to prevent pressure release, hence the direction to reverse the band 1/4″. What we are finding is that we do not need to reverse the metal band, so long as we are not getting them too tight to begin with.”

      A later conversation clarified this issue. Apparently a lot of canners tighten the rings on their lids before processing. And I mean TIGHTEN. Since Tattler lids need to vent a bit during canning, the instructions are to loosen the rings a quarter-inch before processing. But if the rings are merely finger-tightened – not TIGHTENED, if you know what I mean – then the quarter-inch reversal isn’t necessary.”
      Hope this helps.

  • Thank you for the advice on acidifying tomatoes using commercially bottled lemon juice. I recently used freshly squeezed thinking it would be better, then I read your recommendation and explanation– I ran out, bought bottled lemon juice, then reprocessed the whole lot. Thank you Marisa.

  • two questions: must you peel tomatos for canning, & must you add lemon juice – my mom always canned & never added anything.

    1. Conventional practice is to peel. However, I do know of people who skip that step with no negative results. You do need to add lemon juice. Tomatoes have been bred to be less acidic over time, so those that were once just fine for canning, now do not have enough acid to prevent the growth of botulism. Always acidify.

  • Great timing…I’m getting ready to try preserving some tomatoes for the first time! Our tomato plants are doing great! I’m going to use a recipe in Small Batch Preserving…wish me luck!

  • Is there a particular reason that in your picture none of the jars have the ring left on them. When I used to can peppers and tomatoes I left the rings on them even after cooling and they had popped. Just curiosity on my part.

  • This is so well-timed!
    Last year I had some float and a little siphoning with my tomato halves. I’d briefly heard about both and figured they were all safe since they sealed and never developed any off flavors or colors.

    I do have a question though. Are there any tips or tricks for quickly peeling large amounts of tomatoes?
    I blanch, peel, and stuff into quart jars. I assume the tomatoes were hot, then cooled while I handled them, then were reheated during processing.
    How do I avoid that?

  • Thank you for the informative post. I had separation when I canned my tomatoes last week but now I know it’s okay. I do have some questions after reading your post and the comments. First, in the Liquid Loss section, you write “Siphoning can be prevented by better bubbling of jars”–what do you mean by “bubbling of jars”? Second, someone commented that extra head space in jam jars will allow bacteria to form. Do all jars always need to be filled to the top with the exception of the 1/2 inch or otherwise specified headspace? Thank you for such a helpful blog.

    1. “Bubbling of jars” is the process of removing any air bubbles from your jars before applying the lids and rings. If you allow trapped air bubbles to remain in the jars during processing, they will try and escape during cooling and will potentially take a lot of liquid with them.

      Please disregard the commenter who mentioned the growth of bacteria. Headspace has nothing to do with growth of bacteria. If you process your jars correctly, all bacteria should have been killed, so the headspace doesn’t play a role there. Typically, jars are filled to either 1/4 or 1/2 inch, unless otherwise specified. Never fill jars all the way to the top, you need to have some air in the jars in order to create the vacuum seal.

  • My couzin told me that she does a thing called cold pack which her neighbor told her about. I’ve never heard of it. She cleanes her jars, sets them on a clean towel until ready to use, the she boils down her tomatoes and puts them into the clean jars and sets the lids and rings on ad tightenes them finger tight. She doesn’t process them in any other way. Just lets them sit and then when they ping and they are cooled, she puts them away. My question is……is this safe? I haven’t canned in years but I was always taught that you had to process anything you canned, either in a regulaar hot bat canner or a pressure canner. Would love to know the answer to this. Thank you in advance, Sharon

    1. Yikes. It is not safe at all. Tomatoes should always be acidified and processed. If nothing else, she should be sterilizing her jars.

    2. That is Open Kettle canning and it is not safe at all. I have a few old “family heirloom” recipes for pickles like that, and I do not use those for long term pantry storage.

  • Thank you so much for this! I did my first jars of whole plum tomatoes from my garden (just two pints thus far but my plants are loaded!) and had some serious loss of liquid in one of the jars. My seal was good but I was still concerned…but no longer! I’m always grateful for the useful information that I get here. Thanks so much for sharing our knowledge with all of us!

  • Made two batches of jelly, first muscadine and then apple. I followed everything in the instructions and they gelled fine before canning. The jars all sealed and now there is nothing but liquid in them. What is going on with this, it really has me upset.

    Also, a lot of people I know – including me – are scared of pressure canning. I took a canning class but they did not cover that because even the instructor was scared of pressure cookers. I want to can vegetables and most of them require pressure canning.

    1. Jellies can take up to a week to fully set. I recommend putting a jar into the refrigerator and see if it sets up in there. The cold will advance the setting process and give you a peek at what’s to come. I am curious how you knew the jellies were setting when they were still hot and you were filling your jars.

      1. I did the sheeting test and temperature like we did in the class. I actually had the “jelly” form on my spoon for the muscadine jelly.

        If neither set up, I have read I can use the “liquid” as a glaze or syrup. Is that correct? I hate to waste what I have.

    2. I really wish folks wouldn’t be so afraid of pressure cookers and canners. They really aren’t the dangerous contraptions people fear them to be as long as you read the directions and understand what’s going on. In fact, they can’t really “explode.” Usually, what has happened is the safety mechanism has kicked-in (a rubber plug blows) because the user wasn’t following the directions.

      I recently wrote an entire post in my own blog on the subject if you’d like to stop-by and read it. It pertains to cooking in a pressure cooker, but the same safety concerns apply with pressure canners. In fact, most pressure canners are even safer because they come with pressure gauges so you can see what’s going on inside the pot.

      I *love* my pressure canner. I use it to can homemade soups, homemade marinara (for Ragu-like convenience), and even all my tomatoes because the processing time is shorter.

      1. I agree with Justin! They are very safe nowadays and quite the time saver! Just follow manf. instructions–we pressure cook many foods now.

      2. I have been reading about canning, i love canning, find the food very tasteful in the winter, but i beg to differ with a pressure canner not blowing up, mine did not the rubber plug either, the whole lid flew off of it straight up in the air, i will never use a pressure canner again.

  • This was very helpful! I might have done a silly thing… I did not cook or blanch the tomato’s before I canned them just cut them up and put them in the hot jars with the lemon juice then processed them. I was going for crushed tomatoes like you get at the store so I squished them in the jar so their own juice filled in the jar. Was that ok??

      1. Well I though I had.. the book I was using did not say how to prep the tomato’s for canning assuming you read the whole book that talked about that part in the first chapter and it was not until after I was done that I realized that there was special prep… I was my first time doing anything other then jam and jelly so I did not know I was doing something wrong.

        1. I’m in the middle of a batch done just like that, based on a recipe I used last year. They were fine, so I wouldn’t stress over it. I just cut them up, added salt and acidity (vinegar/lemon juice), smushed everything in, and processed in a hot water bath.

  • Thanks for this post, and for answering the questions I sent to you! I feel much more confident about the 25 cans of tomatoes we put up this weekend.

  • Great information and very reassuring. I noticed that you are using some tatler lids. I am still having trouble finessing their use for succesful seals (and getting frustrated in the process!). Any hints on using them successfully?

  • Whenever I can tomatoes I end up with a scaliness on the jars after I pull them out and the jars have cooled, is this from the siphoning?

    1. Do you experience that scaliness with other canning projects, or just with tomatoes? I find that the minerals in water can sometimes leave residue on the outside of the jars. Splash a little bit of white vinegar into your canning pot before processing in order to help prevent that. And then just wash your filled jars once they’ve cooled.

      1. Mostly just with the tomatoes, strange. I have been using the white vinegar to clean out my canning post & the jars but I’ll try adding it first so I don’t have to clean it off. Thanks!

  • Question: for years, I’ve been substituting red wine vinegar for lemon juice to increase the flavor as well as the acidity. Taught that way and we’ve never been sick from canned tomatoes or sauce. From things I’ve read lately, though, I’ve come to question that process’s safety. Anyone know if there is a significant difference in acidity levels? Thanks!

  • Thank you so much for posting this. We had similar questions re: siphoning come up when we made some salsa and pickles (the 13 qts. of tomato sauce was fortunately okay!). Tattler says siphoning can happen when lids are too screwed down too tight during the canning process. Too much internal pressure, maybe?

    Glad to know those pickles and salsa are safe to eat. I couldn’t bear to throw those jars out, but I wasn’t sure what to do with them, either. I did a Google search and asked around, but not having a name or reason for the phenomenon made finding any searching difficult.

    1. When the lids are screwed down too tightly, the air has to work harder to escape and so will often take some of the liquid with it as it forces its way out of the jars. The presence of air bubbles can also lead to siphoning.

  • A friend and I are going to tackle our first tomatoes next weekend, so this post will absolutely ease my mind when some of the above inevitably happen! Thanks!

  • I have a question regarding canning tomatoes although pertaining to homemade ketchup, so perhaps slightly off topic. This is from a friend of mine and I didn’t know how to answer her, because I have never attempted ketchup and haven’t experienced this first hand…
    “Why does my ketchup and red pepper relish darken slightly over time when it is in jars? It is still sealed and tastes fine but it looks unappealing. Am I not filling the jars far enough or should I be processing them finished jars in a hot water bath instead of filling hot jars with hot preserves and sealing them that way?”

    1. That is a natural darkening that happens to some canned food products. It happened to my peach and apricot butters this year. Skipping the processing step has nothing to do with the darkening, though the USDA would prefer that she process her jars.

  • zThe other night I had a jar (tomato sauce) break during canning. So a pint worht of sauce was in the canning water -will that hurt the other 3 jars that were in there canning?

    1. Get the broken glass out of the pot as soon as it is practical. You run an increased risk of more broken jars if you leave it in there to bang around and it may also break into smaller shards. That turns clean-up into even more of a chore. However, when you’re doing a standard boiling water bath and it’s nearly done, you can let it go to completion and deal with the clean-up once the other jars are finished.

  • Here is my question, I canned some tomatotes a few weeks ago. I went to get a jar of them the other day for ratatolie, and they smelled “off”. But the taste was ok. Is that something to be concerned with?

  • Very timely and extremely helpful! Thank you so much for taking the time to share your wisdom and experience. I just started the canning process this year and have found your blog to be a huge confidence booster. I too had siphoning and float and feel much better now knowing that all is right with world since my seals are good! I’m ready for the next batch! Thanks again!

  • This is so very timely! We canned our first batch of tomatoes for the year and had both tomato float and a bit of siphoning, despite being very careful to bubble our jars. Never thought that regular mouths could prevent the floating, that makes sense!

  • The thing about siphoning that worries me is that post-siphon, all the goop from in your jars is now in your canning bath and the next batch you pop in there on a mad canning spree. Does the bath water ever go back INTO the jars?

  • Super helpful, thanks! One quick question about the peaches you mentioned above. If and when the whole canned peaches do discolor (due to liquid loss/ or floating), are they still safe to eat? And for how long? Great blog!!

  • From what I learned there should not be a large headspace like in this photo, as this allows bacteria to form. Isn’t it a 1/2 inch headspace for a quart jar?

    1. When those jars went into the canner, their liquid levels were at the recommended 1/2 inch headspace. They lost liquid during processing.

  • Well, you already answered several of my questions, so thanks! It never occurred to me to pack the tomatoes in tightly to prevent ‘float.’
    When you say siphon, does that mean the liquid actually comes out of the jars? I had a few quart jars (of tomatoes) last week that started leaking liquid right when I pulled them out of the water, but they sealed just fine.

    Do you know why canned tomatoes that you buy at the store never have separation issues, even when the only ingredients listed are tomatoes and salt?

    1. Yes, siphoning means that liquid escapes from the jar during processing or cooling. That is exactly what you experienced with your tomatoes. As far as the store bought tomatoes go, commercial processors have it down to an exact science. If there’s an error, we never see those tomatoes.

    2. I think the answer to your question about the store bought canned tomatoes is that they have equipment that does it all in the blink of an eye.

  • Yay! I haven’t canned tomatoes, yet, but it calms my fears about the yellow beans I canned a few weeks ago that were floating and were affected by what I now know is “siphoning”. Thanks for the information!

    1. I grow a variety of tomatoes and over the years I have learned how to handle the different varieties. I can the big juicy ones (heirlooms and hybrids) and freeze the Roma for making sauce during the cold winter. I take care of the tomatoes in the quickest manner when they are coming in fast and save the more elaborate recipes for cooking on cold winter days. I have just so much shelf space for canned veggies and freezer space for frozen items plus I like to have something comforting cooking away on a bitter day.

      Also over the years I have learned not to fuss over how my canned goods look. I still follow the book that came with my Mirro pressure canner that I bought about 35 years ago. I’ve had it in to the extension service a few times for testing and it is still fine. I used to can for my family but now I can a smaller amount just for myself. Occasionally I use a water bath canner if I have a very small amount. I use a tall stock pot with the PC rack in the bottom. When local produce is abundant it is to your benefit to preserve it for your family and for yourself.

  • perfect timing! i canned my tomatoes this weekend using your guidelines, and was concerned when they separated. fortunately someone in the comments section put my mind to rest, but it is also nice to have it addressed here, thanks!