Some Canning Questions/Answers

December 2, 2009(updated on October 3, 2018)

cranberry apple jam

More than three weeks ago, I asked for your burning canning questions. I intended to be a good canning blogger/teacher and respond right away to those queries, but then life intervened and I’m only now finally circling back around to get you some answers. So here we go…

Jewel asks: I have a few sauce, chutney, and jam recipes that are not specifically meant to be canned, but that I would love to put up. In most cases I believe that the sugar content is high enough for water bath canning, but I want to be safe. Is there a way to tell if a recipe is appropriate for canning? Can you point me in the right direction?

Answer: The best way to determine if your recipes are safe to canning is to look for comparable recipes that have been designed to be canned and determine from there whether the proportions of fruit, sugar and vinegar (in the case of chutneys) are similar to your recipes. I know I always mention it, but my favorite volume for this type of comparison research is So Easy to Preserve.

If you can’t find a similar recipe but are determined to water bath process your recipes, Steve Dowdney includes instructions in his book Putting Up that can walk you through the steps of checking the pH level in your product, in order to determine whether they’ll be safe for water bath processing.

Deb asks: I made applesauce recently. All the jars sealed very well, in a couple the applesauce came up and out of the jar a bit before sealing. I imagine there is applesauce caught in the lid seal area. I can pick the jars up by the lid edge, so they are very tight, but are they really ok?

Answer: It is totally normal to have some siphoning (the technical canning word for when some of the contents of the jars seeps out during processing) with applesauce. However, as long as the jars seal post-processing, they are still safe and shelf-stable. When filling the jars, make sure that you leave 1/2 to 3/4 an inch of headspace, as it will help prevent the siphoning, but rest assured that your applesauce will be perfectly safe for storage in your pantry (or, in my case, the back of my coat closet).

Tracy asks: Tiny bubbles appeared in my applesauce a day or so after canning. Is this normal?

Answer: Yep, totally. I also find that I get tiny bubbles in my processed sauerkraut and in less juicy whole tomatoes.

More q&a after the jump…

Jaime asks: I was wondering if you have any handy tips about adjusting processing time if using a different sized jar than called for in a recipe. Is there a rule of thumb on this?

Answer: Unfortunately, I’ve learned that there’s no specific formula you can depend on to adjust processing time. Typically the processing time will be 5-10 minutes more for a quart sized jar than a pint, but you can’t always assume that. When it comes to processing half pint jars, the rule of thumb is to process them just as long as the recommended time for pints (if the recipe calls for small jars and you want to can it in larger jars, look around for a different recipe or suck it up and use the recommended jars). Again, I recommend looking for similar recipes and extrapolating from there.

Lo asks: How do I can my own creations? That escabeche I love so much? The salsa I can’t get enough of? Aren’t there worries over having ENOUGH acid or somesuch? What about my favorite marinara?

Answer: Like I said to Jewel above, the best place to start is to look for comparable recipes that have been designed for canning. However, some recipes just don’t take to canning well. That fresh salsa that you make during the summer and love so much? There’s no way to can it and have it taste anything like what it does when it’s fresh. As far as the escabeche goes, there are lots of recipes out there that are designed for canning. Take a look at them, and if they line up fairly closely to yours (particularly when it comes to the amount of vinegar) you can use your recipe.

Jessica asks: I was just told that if a canning recipe calls for lemon juice I should always use bottled lemon juice for acidity control. Is that true? I’ve always just used real lemons and wasn’t aware that was a problem.

Answer: It is recommended that you use bottled lemon juice because it has a consistent and dependable level of acidity. This is particularly true when you’re using lemon juice to ensure a safe level of acidity (when canning tomatoes, for example). However, when it comes to recipes where the level of acidity isn’t crucial (for instances, when you’re adding lemon juice to a batch of jam to balance the sweetness), you can use fresh lemons.

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93 thoughts on "Some Canning Questions/Answers"

    1. Hello I am new to canning. I want to can a recipe but not sure where to start. It’s a spicey tomato sauce with sauted peppers, onions, garlic, and seasonings. Any ideas how and if I can even can this? Thank you very much

  • I will toss out that even though canned salsa is nothing like the fresh salsa it is still 100% better with home grown tomatoes than most salsas you can buy in the store.

  • Is there a trick to removing foam from jams before processing? I just finished canning strawberry jam that I painstakingly removed the foam from the top, ran the debubbler thing around the inside of the jar a few times, and now, after doing the hot water bath, there’s foam visable along the sides of the jar! I was hoping to give these as holiday gifts. Thanks for all of your wonderful advice and words of encouragement!

    1. Nancy I’ve found that the best thing to use to remove foam from jam is a mesh skimmer. Something like this works best. Mine wasn’t nearly as expensive though, I use one I bought a an Asian grocery store for $2.

  • Another quick question! I made and canned my first batch of apple butter a few weeks back. The top 1/4 inch or so of the butter in each jar has discolored, going a bit darker than the rest. Is this safe to eat? I’m petrified of giving out food sickness by way of apple butter during Christmas!

    Love your blog,

  • After many years of making and freezing applesauce, this year I canned 3 batches. Everything sealed perfectly, but in 1 batch of jars there’s an inch-deep layer at the bottom in which liquid seems to have separated from pureed solids. Any idea why – or how to prevent this in the future? I love the blog!

  • Can you can hot fudge sauce or butterscotch sauce? I would love to do this for holiday gifts. Not sure if it would work.

  • Angela, unfortunately, the USDA does not recommend canning foods that contain milk products, even in a pressure canner. Those gifts are best made directly ahead of the planned gifting date and then presented with instructions to refrigerate upon receipt.

  • This may be a little off topic, but since I’ve started canning again this month my jars/lids & canner all end up with a white film on them when dry. It’s not that big of a deal since I can just wipe it off with water or soap&water … but it’s kind of a pain. We have very good drinking water from Lake Superior where I live so I dont know what else is in there that is the cause of this. (I dont get this from other things like when I boil water for pasta.) Just wondering if anyone else has had this problem & could it have something to do with the length of time the water is boiling?

  • Heather, from what I’ve heard and read, that white film is mineral deposits. Even the best drinking water often contains minerals. You can help prevent it by adding a bit (maybe a tablespoon or two) of white vinegar to the processing bath.

  • I have looked high and low for information re: cooking my fruit before I’m ready to actually can it. Can I do this? I’m new to canning and my aunt is actually teaching my sister and I how to can this weekend so I thought I would save some time by getting the fruit cooked up ahead of time. Have I ruined it? (We’re making jam)

    1. You don’t really want to cook your fruit into jam prior to canning, because you’ll then need to reheat it in order to can it (your product has to be hot when it goes into jars). The double cooking can impact set and texture.

  • When using my Grandmother’s vintage jars with rubber seals in the water bath, do I cover the jars with water?

    Thank you.

  • Help! I made my second batch of strawberry and raspberry jams yesterday but they arent setting. I used my processor this time instead of smashing by hand. Would that delay setting time or do i need to recook with more pectin? Never had this problem before…thanks!

  • I was wondering about changing sugars and spices in the apple sauce recipe you have in your book “food in jars”. I was wondering if it were possible to use only cinnamon and ginger for spices, and to use brown sugar instead of reg sugar, or even just sub a little?
    on a different note, for the basic salsa could i reduce the jalapenos, 3 seems too spicy for me. i think i am going to give it a try, i was just curious. I love your book by the way. i cannot wait to get a bigger garden next year to make more!

  • I have another question for you! 🙂 for the marinara sauce is says to use a food
    Mill or sieve, do I have to do this step? Or could I simply use an immersion blender to it all then reduce it? I tried used a sieve but it seemed like 3/4 of the stuff what left in the strainer.

  • Your website is terrific! I have a question about substituting canned tomatoes for fresh tomatoes in pressure canning recipes. I live in the Northeast and it’s much easier to get good canned tomatoes year-round than to find good, fresh ones. The recipes I’ve seen on the NCHFP and USDA sites all list fresh tomatoes as ingredients. Can I safely substitute canned tomatoes for fresh ones in these recipes? For example, could I use a 28 oz. can of tomatoes instead of 2 pounds of fresh tomatoes? Thanks! Pete

  • I canned some razor clams last night in my pressure cooker. Does a finished brown/pink product mean it is overprocessed. I had continual pressure for 90 min time( my red button on the handle was up) I have only used my Mirror 22qt twice, so I have difficulty hearing the “jiggle” of the weight. I had hisses routinely and spins and expels of steam about every minute or so. I am sure I had plenty of pressure for the time, thinking the color is an overprocess. What do you think?

  • I canned some strawberry jam today, and when checking the set later tonight, I saw water on top of my jam. Is that just condensation, or did something go wrong?

      1. Hello! I have a similar question to Tonya’s:) I just canned grape jelly (two batches). I did everything according to a tested recipe (Ball), sterilized the jars and lids, and processed the jars for the appropriate amount of time. When I popped open the jars after 24 hours, there was a thin layer of water on top of the jelly and a little on the underside of the lid. The jelly had set almost perfectly. I read that this might be ‘weeping’ caused from too much acid in the grape juice. Will storing this at room temperature cause mold? Is it shelf stable for 12 months? Is it safe to give away to others? Is there anything I can do to lower the PH level if that’s the problem? Thank you so, so much for your help!

        1. That’s just a little bit of condensation and is nothing to worry about. Over time, it will reintegrate into the product. It’s not weeping if you discover it within the first few days of canning.

          1. I had the same thing happen to my applesauce and apple butter I canned last night. All the jars have what looks like condensation on the top of product and the underside of the seal… Am I ok or do I need to pop them open and transfer to freezer containers??

              1. Thank you! I’ve only done jam and tomatoes before and never ran across condensation – I was worried I would have to trash it!

  • Hi, I tried “canning” (I just did a hot water bath for 15 minutes) a salsa fresca yesterday. I made my usual recipe, which I have never conserved before. It is similar to a recipe that I found online, and they used the bain-marie method for 15 minutes. I tested the pH before processing, it was 3.5, which seemed safe to me, but I have doubts, as I probably tested the pH of the liquid, and not the center of tomato or onion pieces. Is this safe? If I were to pressure can this, would it be safe? Should I just put in the fridge and eat in the next few weeks? Thank you in advance!!

  • My son and his girlfriend just tried to can pickles. Boiled in a water bath for 15 minutes. Some of the jar lids buckled, some raised up like a mountain and some sucked in and sealed. We can’t find anything online to explain this and don’t know what to do! It’s a shame, they saved to buy the canning stuff and pickles and may have just ruined everything. Can anyone help us?

    1. Hi Linda, I too canned for the first time and have similar things going on with my tomatoes. I don’t want to kill anyone I give them to, but how do you know for sure if its all safe? Hope someone responds soon!

  • I haven’t canned anything since I was a teenager and had to help my mom put up tomatoes! Now I have teenagers of my own and have been starting to do a little canning. So far I’ve done some peaches and peach butter. Before I continue on to other things, I have a question. Do I need to sterilize my jars just prior to filling them or can I do this step in advance? I feel like I am trying to juggle too many things….blanching/ice bath/pealing/chopping, sterilizing jars, simmering lids, jars in canning pot, etc. I don’t have that many large pots so it’s a little difficult to keep all these going at once. Also, can a person make up a batch of spaghetti sauce, etc. refrigerate it and then can it later in the day if I don’t have a large block of time? Thank you!

  • Hi Marisa,

    I love your book and your blog! I do have a question for you, yesterday I canned the Roasted Corn Salsa recipe from your book (that everyone raves about). The yield was supposed to be 4 pints but I had enough for just over 6 pints. Is it a concern that the greater yield I got would have diluted the acid content enough to not be safe?

  • August 29, 2014 / Hello, my question is…when preparing tomatoes for canning, why is the foam removed?

    1. Huh. I typically don’t remove foam from tomatoes. You do sometimes skim the foam from cooking jam, but it’s truly a matter of taste.

  • I have been canning tomatoes for years and each year I always question whether I prepared them right.
    I clean and heat my jars to to 200 degrees and then fill with boiling liquid, seal, cool under the old blanket method overnight method and store. I may loose a few jars to fermentation but overall the tomatoes in the jars always look good. When I prepare them I always boil for atleast 10 minutes then season prepare and simmer as normal.

    Most of my family does it the same way I get nervous since I always see canning tips to boil for 30 minutes in the jars. If the jars hold the seal, does this indicate it has been properly canned

  • I canned a batch of salsa verde and it appears separated and slightly cloudy on the bottom. All of the seals are good. Should I be concerned? Thank you.

  • Hi Marisa

    I made apple sauce yesterday in quart jars. Sterilized jars, filled with hot apple sauce, left 1/2″ headspace as recipe indicated, processed for 25min (correct for my altitude). After removing them from the water bath, the apple sauce had expanded and is now completely filled up to the rim. The jars have sealed, but i am wondering if they’re safe or should be refrigerated? Another jar I was short on, and left just over an inch of headspace, will that be safe?



    1. As long as the jars sealed, they are totally safe. Chances are that over time, the applesauce will settle back down over time. As far as the jar with extra headspace goes, the top may discolor a little, but that’s not dangerous, just a little ugly.

  • Hello Marisa;

    I’m just about to make your Ro-Tel Tomatoes but in half pint jars. Do I still use the same amount of lemon juice in each jar or should I use less?

  • Hello,

    I just did my first summer garden this year and started to look into canning. Is all canning just jams, jellies and relishes? I have zucchini that I like to prepare as ‘zoodles’ – shredding the zucchini. Can I can the zucchini as zoodles or does it have to be relish?

    1. You can’t can zoodles on their own. You’d need to pickle them in order to raise the acidity levels in the jar to the point where botulism spores cannot develop.

  • Hi, we made applesauce for the first time last week. I did not know that I needed to put the jars in a water bath, and I simply stored the sealed jars in my pantry. Are these jars of applesauce safe to eat? And can I still go back and process them in a water bath now, a week later?

    1. Linda, you could still process. However to do so, you’d need to open them up, empty out the sauce, reheat it, pack it in hot jars, and process.

  • Hi Marisa,

    Last year around this time I posted a question about your Roasted Corn Salsa recipe. I haven’t found the answer yet after much looking around so I thought I’d check back in with you. The question was this: The recipe yield in the book was supposed to be 4 pints, after following the recipe I had enough for just over 6 pints. Is it a concern that the greater yield would dilute the acid content enough to not be safe? I have two batches sitting in my pantry 🙂 – thank you!

    1. I am surprised that you get such a divergent yield, but that recipe has a goodly amount of acid in it and so it should be fine.

  • i was canning pickling tomatoes tonight and when i sliced into a dried chili to add to the brine, i noticed it was moldy. several others in my jar had also molded. i may have used one or two of these dried chilis in a batch of green tomato chutney a few weeks ago, but i honestly can’t remember. i’m hoping if i had, i would have noticed mold. if i didn’t, would 1 or 2 moldy chilis spoil the whole batch (5 pints total)? thanks!

    1. I imagine the green tomato chutney should be okay, since I’m assuming you boiled it for a good, long time and processed the jars to boot.

  • I made apple butter. Canned and processed it 2 days ago. Everything sealed properly but it now seems very thin. Can I open jars,recook and recan?

  • I didn’t notice any question like this but I apologize if it was asked and I missed it.

    I canned about a dozen quarts of Roma tomatoes from my garden last Summer. Most of them are fine (and some made a great homemade pasta sauce last weekend) but one of them did something I’ve never seen before.

    This one strange jar pushed out on the seal part of the lid (as if the pressure inverted due to fermentation). I avoided this jar but haven’t discarded it yet. I don’t plan to use it but I’ve kept it to try to learn exactly what happened and why.

    If you have any insight I’d greatly appreciate it.

    Thank you.

    1. That’s a sign of spoilage. Chances are good that the tomatoes are fermenting or have experienced some other kind of enzymatic activity.

  • I am canning apple sauce – and in one batch I have about an inch of juice at the bottom of the jar with apple sauce above it…all cans sealed well…

    Does anyone know what this means? And if it is a bad thing?

    Thanks in advance!\

    1. My best guess is that you let the sauce cool down and then you heated it up again before canning. Any time you heat, cool, and again heat applesauce, it separates like that.

      1. Thanks a lot for your reply. Yes, that must be it as we didn’t have time to can the batch the night before.
        Is the sauce still okay? Or does that spoil it?

  • I canned some chili sauce yesterday. I realized last night, after all of the jars are sealed and sitting on my counter that I forgot to add the Vinegar! Is the sauce safe, does it have a shorter shelf life, or can I open up the jars yet, add the vinegar and process them again? Thank you!

  • Thank you for putting up such great posts!
    I am new to canning and have canned two batches of apple sauce successfully.
    Last night, I canned my first pickled beets, following a recipe, to which I added a little extra vinegar and water (calculating what I believe to be the correct ratio, and adding a touch more vinegar than necessary to be sure).

    The jars have sealed, and they look good, but there is a reddish splatter (not the purple of the beets) just beneath the lids, on the insides of some of the jars. I assume this is simply sealant from the lids (it’s that same rusty red colour), but I wanted to be sure. Is this normal/safe?

  • Hi,
    I am concerned.
    I didn’t have enough sugar by a 1/2c for canning my beets. I had read that you could lessen sugar amounts inn a recipe.
    Now I read you can’t.

    Should I toss?

    Recipe is for 6 pints. Calls for 5 1/3 c vinegar & 4 cups of sugar.

    🙁 … I think I lowered the sugar in other vegetables I canned.

    Thank You, Barbara

  • Hi Marisa!
    I swear I read it somewhere on your site, but of course can no longer find it- I recall you would recommend tossing the lids that come with newly purchased jars. It does seem like the jars are pressurized and the lids actually come off with a loud pop. The seal seems to be indented and looks used but I’ve noticed that once I put them through the dishwasher that the seal has softened and they look brand new again. My other used lids remain obviously used even after a go in the dishwasher. What’s your take on these lids? Have they been compromised?
    I appreciate your blog so much, it is my canning bible!
    Thank you

    1. I don’t actually recommend tossing the lids that come with newly purchased jars. Unless the jars are really old or have been sitting out in a very hot place, I say that those new lids are fine to use.

  • Hi, I recently canned tomato sauce, and my concern is that I am seeing some “tears” in the lid (on the inside), see the pics in this link:

    Is that fine? My worry is that maybe I screwed the lids too strongly (I didn’t screw the lids “as strong as possible”, but I didn’t screw them only very softly either…I thought that something in between would be meant by finger-tight) so that air could not go out….Not sure.

    Further question: if you think that those tears show there is a problem, is it ok to put the sauces in the fridge and eat them (having past already 36 hours since I canned) during the next days?

    1. It’s normal to have a little condensation inside the jars. It’s nothing to worry about. If you had screwed the rings on too tightly, the lids would have buckled.

  • Hi Marisa – I have some sour cherries that I canned in water in quart sized jars a couple summers ago and I was thinking of making jam with them. Do you know how I could do that? If I did it by weight, as with frozen fruit, should I weigh the liquid as well or drain them first? I wasn’t sure if any of the flavor would have leeched out into the liquid, as the fruit in the jar doesn’t look as vibrant as fresh or frozen cherries. Thanks!

    1. That fruit is not going to make good jam. Have you tasted it? My prediction is that it is going to be nearly tasteless after a couple of years packed in water.

  • I think I read on your site that I can just take your recipe that makes 3 pints and process it the same for 1/2 pints? I just want to be sure as I am giving them as gifts. Thanks

    1. Yes. You can always take a recipe designed for pint jars and move it down to half pints. Just keep the processing time the same.

  • When canning pickles with water bath, why do my pickles float up to the top of jars? Are they good to eat and safe?

    1. That means that you aren’t packing your jars tightly enough. They are perfectly safe to eat, though.

  • I know why you can’t substitute fresh for bottled lemon juice, but are there differences in vinegars that mean you shouldn’t make substitutions? For example, if a recipe calls for white wine vinegar, could you just use distilled? I’m sure balsamic would be a no-no as a substitution, but is there a general rule about distilled, cider, or any others being interchangeable?

  • So, I think I found the answer to my question on your blog after I wrote it–the key is at least 5% acidity?

  • I made a big crockpot of applesauce an thats all i have in it an it brown can i add lemon juice now to lighten color or leave it this way want it unsweetened going to freeze it thanks?

    1. You can certainly add lemon juice, though it probably won’t lighten the color. But the darkening doesn’t make it unsafe. You can freeze it without adding sugar.

  • Hi, Last night I was making your Caramelized Red Onion Jam from Naturally Sweet Food in Jars. It calls for 1 cup or 320 gr maple sugar. I’m wondering how much variety there is in maple sugar–the jar I used, which wdas 12 oz/320 gr was probably close to 2 cups in volume. I started with one cup (didn’t weigh it initially, then I notice the weight of the jar I’d bought), but it had almost no sweetness, really just tasted like vinegar, and wasn’t the right color. I added a second cup, which seemed to be right (tasted much better, darker), but just want to check if I should have any safety concerns given the significant difference in volume with my maple sugar.

    1. I have found that maple sugar can vary in flavor and intensity sometimes, so I imagine that’s what happened here. It should be fine with the additional maple sugar though, because as a dehydrated product maple sugar doesn’t impact the finished acidity the way maple syrup can.

  • When my pickles were ready to come out of the canner I noticed the water level was only up the neck of the jars. They sealed okay ,wondered if this was okay or not.