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Unbalanced start tag short code found before: “ National Center for Home Food Preservation Self Study Course. Module 4. Canning Low Acid Foods: Dial Gauge Canners. Accessed March 2015. ) The Ball company says that if the pressure drops too quickly, your metal sealing lids will buckle: If you are pressure canning, and you bring the pressure …”  Contents hide
Pressure Canning ProceduresHere’s a step-by-step guide to how to use a pressure canner. If you’re looking for information on the “why” — as in, what’s the theory and the reasons behind all these steps, see our page on Pressure Canning Principles. Understanding why can make you better at the how. But let’s get started with the actual practice. 1. Check the pressure requiredBefore you start a recipe or a set of directions, look at the pressure that it requires. Make adjustments in your head based on your altitude because “… altitude increases ….[the] pressure required for pressure canning.” [ref] Andress, Elizabeth. History, Science and Current Practice in Home Food Preservation. Webinar. 27 February 2013. Accessed January 2015. [/ref] Here is a chart of Pressure Canner Altitude Adjustments. 2. Check the processing times required“Always double and triple check your processing times, making sure you’re using the right time for your packing method and jar size.” [ref] Pemmons, Skip (2014-09-14). Next Generation Home Canning: Contemporary and Fun Recipes for Beginners . Kindle Edition. [/ref] Make sure that you will have enough free time to be around for all the time that the processing will take! Don’t forget to allow for about 30 to 40 total minutes of cooling time after the processing time. 3. Check how much water your canner needsFor the modern Presto 16 and 23 US quart canners, it is 3 litres (US quarts.) Other makes and models and sizes will be different. And don’t forget to add a few tablespoons or squirts of vinegar to the water so that your jars and canner stay sparkling clean! To be clear: in pressure canning, you don’t immerse jars fully in water, as you do with boiling-water canning. 4. Load the jars
(Note that the temperature of the water in the pot at this stage has nothing to do with food safety: it’s about avoiding thermal shock that could crack the jars.) 5. Go ahead and ventHave a good vent; you deserve it!
Should the seal ever reveal itself to be faulty during the venting period (which is usually when it does), turn off the heat, remove the lid when it’s safe to do so heat-wise being careful of sudden steam, replace the seal if you have a spare to hand (this is a good reason to), and start all over again, including the full 10 minute vent. NOTE: The venting time required can be longer if you are pressure canning fish or seafood. Follow those venting procedures from your tested recipe. 6. Bring the machine up to pressureWith the venting done, close the vent pipe or pet cock to start trapping the steam inside and start building pressure towards the required amount for your altitude. You might be tempted to crank the stove burner up to its very max in order to help the canner get up to pressure faster. Some people argue, though, advise slow and steady. They feel that it’s best to raise the pressure gradually rather than superfast. They feel that trying to rise up to pressure really fast can result in some liquid loss and seal failures with the jars. This may be particularly important when using Tattler lids to prevent liquid loss. Presto in fact advises to lower the heat a bit in advance before reaching pressure. They write,
You only start timing the actual processing time when the actual required pressure is achieved. 7. Adjust the heatOnce the canner hits pressure, lower the heat down to the bare minimum required to maintain pressure without going under the required pressure. “Regulate the heat under the canner to maintain a steady pressure at or slightly above the correct gauge pressure.” [ref] Marilyn A. Swanson. Using and caring for your pressure canner. Pacific Northwest Extension. July 2013. PNW .421. Accessed March 2015 at https://www.cals.uidaho.edu/edcomm/pdf/PNW/PNW0421.pdf [/ref] 8. Maintain the right pressure — not under and not overYou don’t want run at underpressure but nor do you want overpressure, and nor do you want up and down pressure, even if the up and down stays above the safety range for your product. “Quick and large pressure variations during processing may cause jars to lose liquid.” [ref] Marilyn A. Swanson. Using and caring for your pressure canner. Pacific Northwest Extension. July 2013. PNW 421. Accessed March 2015. [/ref] Overpressure won’t help you, it will hinder you:
If you are using a weighted canner, you don’t want furious rocking and water spewing out: you want just the gentle rocking appropriate for your canner’s rocker The rocking experience is different by brand:
“Generally, weighted gauges on Mirro canners should jiggle about two or three times per minute. On Presto canners, the weighted gauge should rock slowly throughout the process.” [ref] Marilyn A. Swanson. Using and caring for your pressure canner. Pacific Northwest Extension. July 2013. PNW421. Accessed March 2015 at [/ref] All American gives this advice for their machines:
If the pressure drops during processing, you must bring it back up to pressure and start the processing timing all over again. Not the preliminary venting time, but the called-for processing time. “The correct gauge pressure must be maintained for the entire processing time. If the pressure drops below the target pressure, reset your timer and process for the entire recommended processing time.” [ref] Marilyn A. Swanson. Using and caring for your pressure canner. Pacific Northwest Extension. July 2013. PNW .421. Accessed March 2015. [/ref] “If, for any reason, the pressure should drop during processing, the processing time must be recounted from the beginning.” [ref] Dinstel, Roxie Rodgers. Food Preservation. Back to Basics, Lesson 1. University of Alaska Fairbanks Cooperative Extension Service. FNH-00562A. Revised March 2013. [/ref] “Drop in pressure during processing means the sterilizing value of the process will be decreased == Underprocessing. Foodborne illness (botulism) and/or spoilage could result. If pressure drops below target anytime during the process time, bring the canner back up to pressure and start timing the process over, from the beginning. [ref] Andress, Elizabeth L. Pressure Canning and Canning Low Acid Foods at Home. Cooperative Extension: University of Georgia. Powerpoint presentation, slide 32. Accessed March 2015. [/ref] “To have a product that is safe, the heat treatment must be one long, continuous process at the correct pressure.” [ref] National Center for Home Food Preservation Self Study Course. Module 4. Canning Low Acid Foods: Problems in Pressure Processing. Accessed March 2015. [/ref] 9. Processing time is over!At end of the required processing time, turn off the heat. If you are able to lift the canner just enough to move it off the still-hot burner without scratching the stove or dislocating your shoulder or throwing your back out, you may do so. See debate about this at the end of this page. But otherwise, that’s all you can do as far as reducing heat now goes. Here are some estimated cooling times: “Heavy-walled older canners: 30 min full of pint jars, 45 min full of quarts. Thinner wall, newer canners: 20 to 30 minutes.” [ref] Andress, Elizabeth L. Pressure Canning and Canning Low Acid Foods at Home. Cooperative Extension: University of Georgia. Powerpoint presentation, slide 31. Accessed March 2015. [/ref] 10. Let the canner cool on its own, with no monkey business from youYou must let the pressure drop naturally, with the weights and gauges still fully closed, for all kinds of reasons. This natural pressure drop and cooling is vital for safety. During this cool down time, sterilization that the USDA is counting on is still happening. In a pressure canner, the heat-up and cool-down time is counted as heat penetration / sterilization time so don’t try to rush the cool down. See our page on Pressure Canning Principles. “When process time is complete, turn off the heat. Allow the pressure to drop naturally to 0. Rushing this step can result in product loss from jars and insufficient processing.” [ref] National Center for Home Food Preservation Self Study Course. Module 2. General Canning: Pressure Canner Processing. Accessed March 2015. [/ref] The natural cooling is also vital for quality of your canned product. “Do not force cool the canner. Forced cooling may result in food spoilage. Cooling the canner with cold running water or opening the vent port before the canner is fully depressurized are types of forced cooling. They will also cause loss of liquid from jars and seal failures. Force cooling may also warp the canner lid.” [ref] National Center for Home Food Preservation Self Study Course. Module 4. Canning Low Acid Foods: Dial Gauge Canners. Accessed March 2015. ) The Ball company says that if the pressure drops too quickly, your metal sealing lids will buckle:
11. That means, absolutely no forced cooling….Forced cooling refers to cooling the canner by running cold water over it or opening the vent port before the canner pressure drops to 0 psig. Other methods that are sometimes used to force cool include covering the canner with wet towels, wet sheets or wet pillows or bags of ice or frozen peas, or placing the canner in cold air drafts or in a pile of snow outside the back door. We’ve all been there at times — desperate for the canner to open so we can get the next load started. But don’t do it.
Force cooling is just nasty. It may result in [ref] National Center for Home Food Preservation Self Study Course. Module 4. Canning Low Acid Foods: Problems in Pressure Processing . Accessed March 2015. [/ref] :
11. How do you know you’re back to Zero pressure?Different canners indicate 0 pressure in different ways; it is often a plug or piece of metal dropping. After you think you know that pressure is at 0, wait a further 2 minutes (that’s just to make totally sure, to totally avoid any depressurization of jars.) “Wait about 1-2 minutes after pressure drops to 0 psig to make sure all pressure is gone. For some canners, check that locks in handles are released.” [ref] Andress, Elizabeth L. Pressure Canning and Canning Low Acid Foods at Home. Cooperative Extension: University of Georgia. Powerpoint presentation, slide 11. Accessed March 2015. [/ref] Canners with vent-lock pistons are normally depressurized when their pistons drop to a normal position. “These canners are depressurized when their vent lock pistons drop to a normal position.” [ref] Marilyn A. Swanson. Using and caring for your pressure canner. Pacific Northwest Extension. July 2013. PNW 421. Accessed March 2015. [/ref] But occasionally there will still be just a bit of pressure in them after that even. If you are weighted-gauge, do a trial lift of the weight by just a few millimetres. At the first, slightest sound of hissing, drop the weight like a hot potato back down and wait a bit longer. 12. Now that we’re at Zero pressure, how long do you wait before removing the canner lid?Summary: Now wait ten minutes before removing the canner lid. That’s what Elizabeth Andress, head of the National Center for Home Food Preservation, says:
Details, if you are curious: Advice on how long to wait before removing the lid appears to be evolving. Note that none of the varying advice constitutes a safety matter; it’s just procedural opinion. The advice in the past 10 years or so has been: when you are sure the pressure is dropped, remove weight or open petcock and wait a further 10 minutes before opening the canner. Note that this matter is not a food safety issue: it’s a quality issue, largely to avoid liquid surging in jars and seals being compromised. The University of Nebraska-Lincoln says,
Pacific Northwest Extension Services says,
The purpose of this is to let the jars rest; research has shown it helps with sealing success. An extension agent writes,
Elizabeth Andress says in more detail:
Bernardin, in both the Bernardin Guide (2013, page 7) and Ball / Bernardin Complete (2015, page 383), say to only wait 2 minutes after zero pressure to remove the pressure canner lid:
In 2013, the Ball company in its 36th Blue Book said, “After the processing period is complete, turn off heat. Allow the canner to cool naturally. Do not remove the weighted gauge or open the petcock until the canner has depressurized and returned to zero pressure. Remove gauge or open petcock. Let canner cool 10 minutes before removing lid. Unlock lid and lift it off the canner base, being careful that steam escapes away from you. Let canner cool 10 minutes before removing jars.” [ref] Ball Blue Book Guide to Preserving. Daleville, Indiana: Hearthmark LLC. Edition 36. 2013. Page 12. [/ref] As of 2015, Ball’s advice appears to have changed. Or gotten mixed up. The 2015 37th Blue Book (actually dated 2014, but released spring 2015) advises variously 0, 5, or 10 minutes wait before removing the cover. Here’s a 0 minute recommendation on page 13 of the 37th Blue Book: “After the canner has depressurized and returned to zero pressure, remove the gauge. Unlock lid and lift it off the canner base so that the steam escapes away from you. Let canner cool 10 minutes before removing jars. ” [ref] Ball Blue Book. Muncie, Indiana: Healthmark LLC / Jarden Home Brands. Edition 37. 2014. Page 13. [/ref] Here’s a 5 minute recommendation on page 98 of the 37th Blue Book: “Turn heat off, cool canner to zero pressure. After 5 minutes, remove lid. Let jars cool 10 minutes.” [ref]Ibid., Chopped Meat Recipe, Page 98.[/ref] Here’s a 10 minute recommendation on page 118 of the 37th Blue Book: “Remove the weighted gauge after the canner is depressurized — at zero pressure. Let the canner cool 10 minutes before removing the lid…..Allow the jars to remain in the canner for 10 minutes to adjust to the lower room temperature.” [ref] Ibid., Page 118. [/ref] Most individual recipes in the 37th 2015 Blue Book call for the 5 minute wait before removing the cover. HeathlyCanning.com for now still follows the USDA / NCHFP recommendation: when pressure is at absolute 0, remove weight or open pet cock and wait 10 minutes before removing cover. 13. Removing the lidEven though the pressure is at 0, and you’ve waited a bit longer even, know that the temperature inside the canner will still be extreme. Wear oven gloves. Just do it. The time you don’t will be when something goes wrong and you wish you had. With oven gloves on, remove the lid, using the lid as a shield in front of you to direct steam away from your face, because there will surely be a blast of super-heated steam. Pacific Northwest Extension Services says,
Elizabeth Andress, of the National Center for Home Food Preservation, says
14. Remove the jarsSummary: After removing the pressure canner lid, you have the option of going with either advice from Ball and Bernardin, who say say wait a further 10 minutes before removing the jars, OR, going with advice from the USDA and So Easy to Preserve, who say the jars can now be removed with no further ado. If you are using Tattler lids, you may wish to remove them now, so you can tighten the canning rings on them sooner to complete the seal. Details After the lid has been removed, advice about how long to wait before removing the jars ranges from 0 minutes to 10 minutes. Note that none of the varying advice appears to constitute a safety matter; it may be just procedural opinion. The USDA and So Easy to Preserve say that once you’ve removed the pressure canner lid, you’re done: remove the jars. So, zero additional waiting time. Elizabeth Andress, co-author of So Easy to Preserve, says:
Ball and Bernardin differ from that. They both say to leave the jars in the freshly-uncovered pot for an additional 10 minutes — even when they are essentially copying pressure canning recipes from the USDA. Bernardin says,
The Ball Blue Book 37th Edition (2014), however inconsistent it is about wait time before removing the lid, is consistent in saying that once the lid is off, wait a further 10 minutes before removing the jars. At any event, the jars need to be removed shortly after the lid is off. Do not leave them in the canner for a while or over night, with or without the lid on, or you may develop flat sour and ruin all your work. Pacific Northwest Extension Services says,
Set the jars on a towel or wire rack; never directly on a countertop, or the jars may experience thermal shock and crack. When canner is cool enough to safely lift, tip out the canning water into the sink. Rinse out the canner, and the lid, being careful not to get any gauge wet. Set aside to dry. 15. Finish the jarsLet jars cool for 12 to 24 hours [Ed: uncovered with towels etc, and not near open windows with icy drafts.] Remove screw-on rings (or clamps if you used Weck or Vacola.) If any rings are stuck on the jars, stand jars upside down in enough warm water to cover the rings for a few minutes, then remove rings. Gently and cautiously lift each jar up a bit by the actual lid. If it stays on, you have a seal. Wash the jar. Set aside to dry. Then label with food product, month and year, and batch # if appropriate. Store. Let canning jar rings air dry then store separately. If any jars didn’t seal, put in fridge and use up within a few days, or freeze if appropriate for that food product [ref]Tip! Ensure correct freezing headspace.[/ref], or reprocess (after wiping rims and with a fresh lid) if you have another similarly timed batch coming up very soon. _______________________________________________________________________________ Big Debate: Move the pressure canner or not when processing is finished and you have turned off the heat?The experts disagree about whether you should move the pressure canner off the burner when the processing time is finished. HealthyCanning.com presents the conflicting advice to let you decide. What are the University Extension Agents saying?The University of California says,
Clemson University says,
The University of Alaska says,
Pacific Northwest Extension Services says,
What do the canner manufacturers and the USDA say?Mirro is silent on the topic; page 35 of the manual just says, “turn off heat. Let canner cool.” The All-American manual, page 9, says, “Turn off the heat… Do not move the pressure cooker until the pressure is completely reduced.” Here’s what Presto advises for their pressure canners, and what the USDA in fact advises for all pressure canners — they both seem to want it off the burner when processing time is up: Presto says,
The USDA says,
Note the USDA says “if possible.” It could be that’s your out for not giving yourself a week in hospital with a hernia, if the canner is just too heavy. So Easy to Preserve has perhaps the most practical, detailed advice of all, as usual:
But whatever you do, whether you move it or not, note that the weights, vents, petcocks, etc, are all to be still fully in place at this point. Further readingAndress, Elizabeth. “History, Science and Current Practice in Home Food Preservation.” Webinar. 27 February 2013. Andress, Elizabeth. Preserving Food: Using Pressure Canners. University of Georgia Extension Service. June 2011. Swanson, Marilyn A. Using and caring for your pressure canner. Pacific Northwest Extension Publication. PNW 421. July 2010 revision. University of Minnesota: online pressure canning tutorial. Pressure Canning Step-By-Step Pictorial. University of Nebraska video. 2009. (note that Ball has since said that heating lids is no longer necessary.) Do you cover jars with water when pressure canning?FAQ – Do the jars need to be covered with water when pressure canning? No, jars do not need to be covered like in a water bath canner. Set the rack on the bottom of the canner and heat water until hot, not boiling. Keep warm.
How long does it take a pressure canner to build pressure?A loaded pressure canner requires about 12 to 15 minutes of heating before it begins to vent; another 10 minutes to vent the canner; another 5 minutes to pressurize the canner; another 8 to 10 minutes to process the acid food; and, finally, another 20 to 60 minutes to cool the canner before removing jars.
What foods need to be canned in a pressure canner?Pressure Canning Methods: Pressure canning is the only safe method of canning low-acid foods (those with a pH of more than 4.6). These include all vegetables, meats, poultry and seafood. Because of the danger of botulism, these foods must be canned in a pressure canner.
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How do you use a pressure canner
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