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!
Thank you for answering my issue. My directions said to dip in boiling water to peak the skins and core. Then it said to bool and put the hot tomatoes into the hot jars. Is this double boiling the which breaks them down and prilosuxes the liquid we r talking about?
That’s a pretty traditional approach to peeling tomatoes, so it doesn’t worry me all that much. Typically the double cooking refers to tomatoes cooked into sauce, cooled, and then reheated. But if they spent a lot of time in the boiling water there is a chance that they could have some separation.
My friend told me that she cans her tomatoes in an open kettle method. As her mom did. They cook the tomatoes for 45 minutes, boiling them . Then put them in jars and they seal. They put a teaspoon pickling salt, a tablespoon of sugar and a quarter cup of purchased lemon juice in a quart jar. Is this safe
That technique isn’t in alignment with current canning standards and will produce a product that would be far more likely to spoil. It’s not a method I would endorse and instead would recommend that you water bath process your jars according to the guidelines issued by the National Center for Home Food Preservation.
I canned quart tomato sauce the other night, a few of the jars have about 1/2 inch of clear liquid in the bottom?
all the jars seem to be sealed I did a water bath for 40 min as instructed. But it look as though some of the jars have tomato sauce around the rim when I remove the metal ring but top is on tight but can see tomato residue around it? Is this sealed right ?
Not sure if 1/2 of liquid in bottom of jars is water that seeped in? new at this
Did you read through this post? Both of those experiences are totally normal. Tomatoes separate if they are heated, cooled and heated again. And some siphoning (the experience of having a bit of product seepage out the edges of the lid) is also normal. As long as you followed proper canning instructions and the lids are sealed, they are still entirely safe.
I slightly softened my tomatoes, put them through my tomato sauce machine, filled my jars and boiled them in an industrial size barrel. The jars finished boiling at 7 pm Saturday evening. I believe the lids were overtightened because when we took them out the next morning, the lids were buckled. So we quickly removed the lids and put new boiled lids on. We reboiled the jars at 9:30 Sunday morning. Do you think any exterior water seeped through? Do you believe the tomato sauce will be safe to consume? Do think I can store my jars on my shelf and if so, for how long?
I don’t imagine any water seeped in. As long as the second set of lids sealed well, they should be fine.
I was canning marinara sauce. I put it in hard boiling water with 1 inch above each jar. I did that for 35 minutes as instructed. When I removed the lid, the water was below the top of the jars. Is this going to be a problem.
It sounds like you had some evaporation as the water boiled. The jars should be okay, though it is ideal to start with enough water that the jars don’t boil to exposure during the canning process. Next time, check the pot halfway and top it off with some boiling water from a kettle to prevent this from happening.
How long do I actually need to cook whole tomatoes. My canned tomatoes are mushy and when they get done canning, I’ve got half liquid and half tomatoes but now I froze my tomatoes this time because I wasn’t making enough tomatoes to can. This year I’m going to try just going ahead and canning three or four cans. If that’s all I’ve got or jars I mean. What are some hints you can give me so that my whole tomatoes will remain firmer
For firm tomatoes, you don’t really want to cook them all that much. You want to score the ends, blanch them in boiling water and then shock them in ice water to ensure they hold their texture. The boiling water bath will soften them some, but keep the initial cooking as short as you can.
Out of 7 quart jars of tomatoes, 3 were wide mouth, all floated, 4 narrow (regular) 1 floated, 3 sank. The floating tomatoes don’t bother me, the sinking tomatoes were the ones I was worried about. Like if they had a proper seal or not. But they all appear to have sealed.
Don’t worry about sinking tomatoes. That simply means that the tomato was fully cooked and without air pockets when it came out of the canner. They are safe to use, but will probably be quite soft.
I can’t tomato juice about a week ago and don’t remember if I put lemon juice in the jars can I reheat it put lemon juice and red jar and boil
Yes. Open, reheat, fill jars with lemon juice and process like it was the first time.
When I took my jars out of the hot bath some tomato liquid leaked out onto the towel. The kids are sealed and do not move when pressed. Are these good or should I toss them
That is totally normal. If the seals are good, the jars are fine.
I had plenty of tomatoe juice left over from canning my tomatos so I decided to can the juice. Most of the red juice has disappeared, floating at the top with yellowish colored water beneath it. Is it worth saving?
That sounds pretty normal. It should still be good. Shake it up and see if it reintegrates.
In my canned chili base that I hot watered bathed, there are actively moving bubbles as soon as I took them out of the canner. Would these be ok to refrigerate after cooled and use within a week?
Let the jars sit undisturbed for 24 hours before worrying about bubble movement. The bubbles you saw were normal cooling activity, not a sign of fermentation.
Your pic above is extremely helpful! Love how you explain things too.
I have a ball electric canner for water bath. Halfway through the canning process the water will stop boiling and start back boiling in 3 mins. My jars always seal and year after year we eat the marinará sauce. Any explanation on what’s happening?
It sounds like it might be an issue with your canner or the power source, as it should not do that. I don’t remember seeing my electric water bath behave in that way.
My canned tomatoes have settled in the jar and now I have noticed some siphoning. I canned them 4 days ago.
That’s okay. As long as they were processed for the correct amount of time and the lids are firmly sealed, they are fine.
Hi there I did can some crushed tomatoes for the first time. Followed the recipe did, then did the de-bubbling and the topped up the jars to the 1/2″ head space. Did the water bath for 35 minutes as they are pint jars. Once done I carefully lifted the jars out and let them stand on the counter for about 24 hours to cool and did hear all the lids ping so I have a good vacuum but the next day I did notice some bubbles and the level in a couple of the jars dropped slightly below the 1/2″ head space. Do you think they are okay? I don’t want to make anyone ill. Secondly the way I was preparing the tomatoes was a few at a time in soft boiling/simmering water for 1 minute and 30 seconds in cold water. Skinning the tomatoes chopping them and throwing them into a hot pot and crushing them. Can I do a whole bunch of tomatoes say like8-12 cups at once then put them in cold water skin them throw them in a food processor and then put them in a pot to simmer ? Any advise would be greatly appreciated. Thanks
What you’re describing is totally normal in terms of the settling of the product. As long as the bubbles aren’t actively moving, they are fine. Bubbles are only an issue if they are moving as if the product is fermented. And yes, you can do the tomatoes in larger volume.
I canned 8 quarts of tomatoes over two weeks ago, they all looked sealed. Two nights ago one of the li
ds BLEW OFF ONE JAR…just found it today. Now I’m afraid to eat from the other jars! What in the world caused it?
It sounds like you didn’t process them properly and they fermented. That’s what would cause that kind of explosion.
I just canned pureed tomatoes for the first time. I usually freeze them and am so sad I didn’t do this because my canning results are awful! I pressure canned (for the first time) and all of the puree is on top of water. Also, one share lost a lot. The jars cooled down in the canner so I don’t think it was cooling too fast. Question, can I reprocess the five jars I have and should I just reheat ad boil for 5 minutes. I did not do this. Pure tomatoes that had been roasted and then pureed. Thank you.
Tomatoes don’t do well in a pressure canner. You get a much better product in a boiling water bath canner. I would not reprocess the jars, as it will only make the quality of the product decline. If the jars are sealed, store and use them.
I’m not sure but I think my girlfriend overcooked my stewed Tomatoes. I put them in the pressure cooker and when I came back 2 hours later she had already taken them out of the pot. The liquid is dark brown and the vegetables are dark. I really doubt there quality is good enough to eat. Would you toss or eat? They all sealed
I’d probably open one jar and try them in something to see the quality.
My question is regarding jarred crushed tomatoes for sauce, some jars have 1 inch if space at top.
But they are properly sealed. Will the y spoil?
It’s not ideal but if they sealed properly it’s okay.
I made stewed tomatoes but 2 of the jars are right under the fill line. Im new at canning and didnt know there was a fill line. They are sealed but I was told they are bad if not filled to that line and its barely under.
It’s not ideal, but as long as the jars are properly sealed, they should be okay. Just make sure that you use those jars first, as they won’t hold their quality as long as jars are more fully filled.
I water bath canned a batch of plum tomatoes last night and three of the five jars did not seal. In addition I had a lot of siphoning, if that is still the term here, even though there shouldn’t have been the water pressure differences as with pressure canning. I used my pressure canner sans the overpressure plug per the instructions, but there was barely enough headspace to keep my quart jars covered. Could this have been the problem? I don’t have anything taller to use, and I don’t like cooking my tomatoes to smithereens in a pressure canner. Maybe acquiring an actual water bath canner is in order but if this is not the problem it would just be yet one more pot to store.
Were they raw packed tomatoes? Because that style of tomatoes can siphon a lot because of naturally occurring air in the tomato flesh. It does sound like you would benefit from a pot large enough to keep the jars fully submerged. A pressure canner doesn’t do that particularly well.
Can I use ketchup for my sloppy joe recipe it does call for addition vinegar, brown sugar,onion, I bring to simmer and water bath for 15 minutes is that to process
I’m so sorry, but this is outside the scope of my ability to advise.
Do you know why the lids of homemade passata might come off during water bath cooking. We made a large batch and even had the same person put on all the lids to ensure they were the same level of tightness but had quite a few lids come off during water bath. We haven’t been able to find much information about why this might happen
Were they bottles with lug lids? Those do often need to be tightened more aggressively than jars with lids/rings do. It could be that the water was boiling too vigorously and agitated the jars/bottles too much.
My method for canning tomatoes is to blanch first to remove the skins, cut them in half to check for black spots and if there are I throw them out, after cutting in half I put them in a large pot to simmer for a few mins and salt them. When I fill them occasionally I will end up with the last jar not being filled all the way up to the 1/2″ to 3/4″ headspace that’s required. I have grabbed a few tomatoes and blanched them to remove the skins but instead of cooking them too I cut them in half and put them into the jar of hot tomatoes to fill it up. I figured it should be OK since raw packing is a thing but since I am pretty new to canning thought I should ask. Thanks!
The issue with what you’re doing is that the jar with the raw packed tomatoes has a lower internal temperature and so will need a longer processing time to ensure that all bacteria is killed. I’d suggest that you give that last jar a little extra time in the canner. Or, mark that one to use first.
I am wondering if it is okay to can a half full jar of tomato salsa. I did it, along with full jars, and it sealed. Is this salsa safe to keep for several months?
You never want to process jars that are half full. There is the risk of floating during processing that can lead to breakage, along with the fact that there is just too much air in the jar to fully vent during processing. You either want to quickly heat a smaller jar, or put the half full jar in the fridge to be used promptly.
That’s not exactly how or why tomato separation occurs. Tomatoes release an enzyme that breaks down pectin when they are cut or crushed. The way to keep separation from happening is to heat your tomatoes immediately after cutting them to kill the enzyme.
I did not cook peel tomatoes before canning, raw packing with water bath. Will they be ok?
As long as you processed them for the correct amount of time, they should be fine.
Hi Marisa, Your recipes and content are fantastic, I love following you on social media. Question – I canned salsa last night and thought I reached 1/2 headspace, looking at the jars today it looks closer to 1 inch. Will the salsa still be shelf-stable? I’m hoping to avoid reprocessing the salsa. Thank you.
That’s a relatively minor issue. As long as the seals are good, they should be fine. Tomato products can siphon or settle sometimes.
Just finished canning tomatoes with water bath, and next day there is a sediment (black) in bottomof jar. I used quart jars with citric acid,salt sugar in correct measurements. I have never had this happen before. What could this be and are they safe. Also 1 jar has bubbles. Your help is appreciated. 38 quarts, and sediment in about half.
That’s totally normal. And as long as those bubbles aren’t moving like they are carbonated, they aren’t an issue.
I just noticed a jar of my crushed tomatoes didn’t seal. It’s been about 24 hours since they were canned so they’ve been out on the kitchen counter. Should I use them or discard?
Refrigerate and use promptly.
I heated my tomatoes that I was using to make tomato juice in my aluminum pressure canner. I also use my pressure canner to heat my juice to boiling before I put it in my hot jars. To finish is it safe to use?
Aluminum pots don’t make things unsafe, but they can impart a metallic flavor to the finished product. Taste and if it seems okay, you can proceed.