The “Low-Temperature Pasteurization Treatment” is a low and slow method for processing home canned jars of pickles.
Respected home-canning author Linda Ziedrich writes,
Many people hesitate to subject their pickles to a lot of heat for fear it will ruin the texture of the pickled foods. A boiling water bath can definitely soften cucumbers and some other vegetables. For this reason a scientist at the University of California developed the low-temperature pasteurization method for home picklers. By this method you don’t boil your jars, you just immerse them in 180 to 185 F (82 to 85 C) water for 30 minutes.” [1]Ziedrich, Linda. The Joy of Pickling. Boston, Massachusetts: The Harvard Common Press. 2009. Page 21.
The procedure was added to the “accepted canon” of USDA procedures in 1988. [2] “1988 low temperature pasterurization process introduced for some pickles was added to USDA complete guide. Andress, Elizabeth. “History, Science and Current Practice in Home Food Preservation.” Webinar. 27 February 2013. Accessed January 2015 at https://nchfp.uga.edu/multimedia/video/nchfp.wmv
The National Center for Home Food Preservation (NCHFP) gives further details:
Low-temperature pasteurization treatment: The following treatment results in a better product texture but must be carefully managed to avoid possible spoilage. Place jars in a canner filled half way with warm (120° to 140°F / 50 to 60 C) water. Then, add hot water to a level 1 inch (3 cm) above jars. Heat the water enough to maintain 180° to 185°F (82 to 85 C) water temperature for 30 minutes. Check with a candy or jelly thermometer to be certain that the water temperature is at least 180°F (82 C) during the entire 30 minutes. Temperatures higher than 185°F (85 C) may cause unnecessary softening of pickles.” [3] National Center for Home Food Preservation. Preparing and Canning Fermented and Pickled Foods: Low-Temperature Pasteurization Treatment . Accessed June 2015
Only use with tested recipes that allow it
There’s a catch though: this process cannot be used for everything. You only use with the approved recipes that say they are made to use this process.
The NCHFP says, “Caution: Use only when recipe indicates.” [4] National Center for Home Food Preservation. Preparing and Canning Fermented and Pickled Foods: Low-Temperature Pasteurization Treatment . Accessed June 2015
Ziedrich says that goes for her recipes, too: “[My] recipe instructions indicate when this method can be used.” [5]Ziedrich. Page 21.
Oregon State University Service cautions that the low temperature pasteurization method should not be used with reduced-sodium pickles.
Perhaps the wording is poor, but it almost would appear to open the door to any cucumber pickle recipe for the low-temperature process. One would need to ask them via the NCHFP for clarification but in the meantime, there’s lots of other caution about using it only with recipes that call for it.
Oregon State University Service cautions that the low temperature pasteurization method should not be used with reduced-sodium pickles: “Do not use low temperature pasteurization method for processing pickles when making reduced-sodium pickles.” [7] Food Safety & Preservation: Low Salt Pickles. Oregon State Extension. SP 50-533, Revised February 2013. Accessed June 2015 at https://extension.oregonstate.edu/fch/sites/default/files/documents/sp_50_533_lowsaltpickles.pdf
They do not say why.
Many end-users feel that it is problematic that this technique is in effect only endorsed with one or two recipes, and hasn’t been tested further for validated, wider application.
Making altitude adjustments when using low temperature pasteurization treatment
When using the low-temperature pasteurization method, no altitude adjustment is needed, either in terms of time or temperature. The reason is that you are controlling and monitoring the temperature of the water with the aid of a thermometer, so you are going to reach and hold it between the target range at whatever altitude you are at.
Iowa State University Extension says,
Do not change the processing time.” [8] Francis, Sarah. Canning: Pickles. Iowa State University Extension. PM 1368. September 2014. Page 3.
Some home canners say that the low temperature pasteurization method is particularly important for those who live at high altitudes. They say that a 10 minute boiling water bath at sea level can end up being 25 minutes for people at high altitudes, after adjustments, and few if any pickles will survive being boiled that long.
Miscellaneous notes
The low temperature pasteurization method can be used with pint or quart size jars, apparently, when your tested recipe indicates. [9] Viz the recipes in: Paul, Lynn and Alice Bautz. Canning Pickles and Sauerkraut. Montana State University Extension. MT199607 HR Reviewed 3/2006. Accessed March 2015 at https://store.msuextension.org/publications/HomeHealthandFamily/MT199607HR.pdf
The low temperature pasteurization method might be where an electric water bath canner (such as those made by Ball, Weck or Fowlers Vacola) with a thermostat would come in handy, so you don’t have to stand by the stove for 30 minutes and watch a thermometer like a hawk.
At the end of the 30 minutes, you immediately remove the jars from the canner — you don’t give them the traditional 5 minute rest period in the canner. “Immediately remove jars from the canner at the end of processing time. Put jars on a rack or cloth so air can move freely around them.” [10] Pickling Vegetables. Pacific Northwest Extension. PNW 355. June 2008. Page 5.
Further reading
National Center for Home Food Preservation. Preparing and Canning Fermented and Pickled Foods and Preparing and Canning Fermented and Pickled Foods: Low-Temperature Pasteurization Treatment
References
Jim
Can low temperature pasteurization (180 to 185) be used when canning peaches?
Healthy Canning
Wouldn’t that be nice if someone got the funding to test using the low temperature pasteurization method with more products! But they haven’t yet.
Donna S Hutchison
Where can I find this thermometer with the holder?
Harry
Do you need to pre-seterilize jars when using the Low-Temperature Pasteurization Treatment? Or can you just use clean jars like any other time the processing will last more than 10 minutes?
Healthy Canning
This is a very interesting question. None of the usual reputable sources address the question of whether the jars should be sterilized first or not, and if not, why not. It is as though they assume there is no need to, but, we couldn’t find anything specifically to cite on that one way or the other. Sorry we weren’t able to find an answer for you!
Heidi
For low-temp pasteurization, is it plausible to use a sous-vide machine in the pot to maintain the desired temperature versus a stove top and monitoring the thermometer? I already have the sous-vide and it would use less energy and put off less heat in the summer than my stove.
Brian H
Oh heck yes.. That with hold the temp perfect.. set it for 183 F or 83 C. That circulating water will really give a super even application of temperature to the jars to top to bottom.. Excellent penetration IMHO. For this pickle recipe only, nothing else..
amdunne
There is a recipe for bread and butter pickles available from America’s Test Kitchen. The process is the same except to start water at 120 degrees with the cans and raise to 180 degrees before starting timing. The results are very good.
Tom
I assume that since there’s a great big thermometer hanging out of the pot, you do not cover the pot with a lid like traditional water bath canning. Right?
Thanks, Tom
Casey
What about using a Sous Vide for low-temperature canning? In particular, I’m interested in canning Apple Pie Filling. Can you advise?
Healthy Canning
Aside from dill pickles, I’m not aware of any tested recipes for lower-temperature pasteurization of a home-canned product. In fact, I think I can guarantee that no reputable source offers any at the present time, but, you can check with some of these Master Food Preservers groups to see if they have heard of any. https://www.healthycanning.com/master-food-preserver-help-groups/
But, you don’t need the expense of a Sous Vide set up to can apple pie filling. A good old-fashioned, inexpensive boiling water canner will do the trick — or, you can freeze!