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Canning 101: Siphoning

October 13, 2010

When Matt and I first started canning last August we really didn’t have a clue…a clue about a lot of things.  Through lots of trial and error, reading, and canning we’ve figured out a thing or two.  Afterall, practice does make perfect.

But, some things still do occur from time to time and you are left wondering why?  SIPHONING.  Siphoning is when liquid is drawn out of the jar by a rapid change in temperature and air pressure.  It seems to occur more frequently in canning fruits like apple sauce and peaches in syrup but we’ve also experienced siphoning in soups and stewed tomatoes done in the pressure canner. 

Remedy: Some of the ways to solve this problem include…

  1. Make sure that the jar and liquid is as hot as it can be when filling.  I think that this is a good habit to get into.  The hotter the jars are when they enter the boiling hot water processor the better.  It prevents liquid from seaping and jars from breaking. 
  2. When using the boiling water canner be sure to remove the lid and turn off the heat when the time is up.  Do NOT remove the jars.  Let them rest for 5 minutes so that they can cool down slightly before removing.  Often this is enough to prevent siphoning.
  3. Remove air bubbles and adjust headspace accordingly.  This is an important step and can also help to prevent siphoning.  If you’ve left pockets of air in your jars it may result in liquid being incorrectly dispersed.  Today, while doing the spiced apple pie filling I didn’t pack the jars tight enough…leaving unwanted pockets of air and room for the liquid to boil out of the jar.  This prevented them from sealing.

Jars may seal despite unwanted siphoning and when they do they are perfectly safe to label and store.  Last year, every can of 30 jars of peaches siphoned.  At the time, we weren’t sure why?  Now we know.  We labelled and stored each jar of peaches and 12 months later we finished the last one.  They all tasted just fine.  However, liquid loss does spoil the overall appearance of what should be a beautiful jar of fruit.  Try your best with the above suggestions and you may eliminate siphoning in most cases but don’t panick if you have a bit of liquid lost.  Just be sure to remove your rings and clean the jars before storing them on the shelf. 

Jars that are not cleaned before labelling and storing can look like this after a few months on the shelf…YUCK!

16 Comments leave one →
  1. October 13, 2010 7:27 pm

    Thanks for the great tips. I’m new to canning so this is great to know.

  2. sgmsgc permalink
    January 11, 2011 10:07 am

    Thanks for the info. I am a new canner, received a Fagor Duo for Xmas, and am trying to get it right.

    Siphoning is problem for me. I have a conventional electric stove and the Fagor Duo. My sis-in-law gave me a recipe for raw packing venison where she fills the jar with hot broth then processes. I had siphoning. I read the USDA manual and it said “don’t add liquid to raw pack” so I did as they said and had siphoning. The last batch I processed last night, I tightened the lids past just finger tight. I didn’t pipe wrench them, but got them tight. I had siphoning. If I raw pack without liquid, do I need to worry about airpockets?

    So I think my process sucks. I read this morning about changes in temperature. Previously, I had read that you shouldn’t change temperature settings after you reach pressure.

    SO what I have been doing is I fill and the seal the canner, set the pressure to HIGH (15lbs, I am only 700 ft above sea level but the only other setting on the Fagor is 8lbs and that seems to low for meat) then I crank the heat until I get steam, then I lower temp to the 3 where I know it will hold the same pressure throughout and I don’t touch it again. I think I can smell the siphoning during the processing. After processing, the Duo has a release valve. I relieve the pressure using that and unload the jars.

    If I put my burner on 3 from the start, it will take a month to build pressure. SO should I bring the water to a boil, place my cans in, and then seal and set at 3? Should I use the natural release method to drop my pressure?

    Please help.

    • January 11, 2011 12:53 pm

      Let’s see if we can help because the siphoning was definitely a frustrating issue for us as well but we eventually got it to work about 100% of the time.
      First, the raw-pack method is simply when you put prepared but unheated foods into hot sterilized jars and then cover the food with hot liquid. Using this method is more likely to cause fruit float because air can be trapped in both the food and the jars…and it may cause more siphoning (not sure). Honestly, we have never used the raw pack method but we were going to try it with our 4th batch of sauerkraut. We always heat the food we want to process and then pack it into hot sterilized jars.
      Siphoning…it sounds like you are doing everything right (getting the temp up on high and then reducing it to maintain the pressure) but at the end when your time is up you may not be letting it cool long enough. That was our problem. When the time is up (1) turn off the heat (2) let the pressure come back to zero (3) wait a little longer (4) release the valve (5) open the lid and let the jars seal inside the pressure canner. Waiting longer allows the extreme heat within to come back down more slowly which will reduce the siphoning. Are your jars sealing?
      Admittedly, the siphoning does have an odor and can leave food tasting tinny…Matt claims that all our soup (though it sealed fine with very little or no siphoning) tastes a little tinny. Please let me know if this answers your questions and if not just leave another comment!

      • Margaret Bonifay permalink
        July 6, 2013 11:43 am

        I have been canning for over 40 years but made a mistake yesterday while canning ham. I used pressure canner, used hot pack method. Cleaned jar lids very very good. When I took them out of canner there was grease in the canner water and also on my jars. Now I am worried whether to redo them or not. I opened one jar and it was tightly sealed. Can I wash off the outside of the jars, take off the screw bands and still keep them in pantry? It is hard to understand how the seals tightened so well. HELP Maggie

      • July 6, 2013 5:23 pm

        As long as you used a pressure canner and got the temperature up to the correct pressure and for the length of time required (80-90 minutes depending) it should be fine. There can be seepage during the process that accounts for the grease in the water and on the jars. Check the seals and clean the jars off and it should be fine.

      • sgmstv permalink
        July 9, 2013 10:47 am

        Thanks to everyone here. Yes, I was cooling my cans too rapidly and caused the contents of the jars to siphon out. I think of it like this…it is akin to taking the lid off the pressure canner before its cool. The same chemistry that would make your canner explode makes your jars siphon.

        i mostly can venison, beef and chicken. I have noticed that if I don’t have enough headspace, I will have grease seep out. I haven’t had any problems with lid seals or spoilage.

        I always wash my canned jars the next day in soapy water.

  3. July 3, 2012 2:36 pm

    thank you! I made some apricots in syrup a few weeks ago after doing some glorious pie plums last year. the syrup ended up everywhere but the jar, or so it seemed. I have 10 lbs of apricots in the kitchen right now and was hesitant to do more in syrup; your post has given me the information and confidence to try again.

  4. October 10, 2013 7:05 am

    Hello there! Would you mind if I share your blog with my myspace
    group? There’s a lot of people that I think would really enjoy your content.
    Please let me know. Cheers

  5. Judy permalink
    July 20, 2014 7:45 pm

    I have been canning crowder peas and have had a problem with siphoning. After doing research, I think my problem has been 1. not leaving enough head space 2. filling my jars too full (because peas absorb so much water during processing 3. opening my canner as soon as the pressure reaches 0. Another run has just finished processing. Will see how it all turns out. Glad to know that I don’t have to reprocess the siphoned jars, but they certainly aren’t very pretty.

  6. Love & Wild Honey permalink
    August 4, 2014 4:49 pm

    I shared this article on my site as one of my readers was inquiring about siphoning in one of my recipes. Thanks for the thoughtful answer!

  7. Neka Mire permalink
    November 10, 2014 7:01 am

    I made satsuma marmalade yesterday, and I used my headspace measurer to make sure they were filled to the proper height. I processed them as directed, and I noticed after they cooled there was a TINY bit of marmalade that leaked out. I wiped it off. All of the lids popped as they cooled down. I plan on using these as gifts, should I re-process, or are they ok to gift like this?

    • January 1, 2015 11:33 am

      Sorry to not have responded sooner Neka. There would have been no need to reprocess…siphoning in many cases is very natural and as long as the jars have sealed your marmalade would not be affected.
      I bet is was super yummy!!


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