Let’s talk canning basics: Pressure Canning

Pressure Canners and BWB canners are similar … and–at the same time–very different.

They’re similar in that they both use the combination of a metal pot, water, and heat … in order to kill bacteria in a glass jar of foods, and to air/heat/pressure seal a two-part lid against the top lip, creating an enclosed environment inside of the canning jar. In other words, your final product–a sealed jar of food–looks pretty much the same after going through a Pressure Canner as it does after going through a BWB canner.

Beyond that, however, differences between the two start to appear rapidly.

First and foremost, a Pressure Canner adds a crucial element into the mix that you don’t get from a BWB … and that’s pressure. Thanks to the way they’re engineered–when the heat inside a Pressure Canner gets high enough, right about the boiling point–the rubber gaskets and metal parts expand against each other, turning the pot into a sealed environment. Then–once that pot seals–the pressure starts to build up inside rapidly.

It’s that pressure that makes the magic!

At sea level, an open pot of plain water boils at 212 degrees. Adding different chemicals or substances to that water may throw your boiling point a few degrees in one direction or the other, but 212 degrees is considered boiling point. And once your water reaches that point … it doesn’t matter how long you have the heat running beneath that pot, or how high you turn it up from there … the water in that pot will NEVER get hotter than 212 degrees/its boiling point.

That is … unless you put that water under pressure. Under pressure, water (and, subsequently, food) can reach temperatures upwards of 230 degrees … 240 degrees … even 250 degrees in some cases … thanks to the pressure in the pot!

Why is this important?

It’s important because some strains of canning cooties–most often, those found deep inside low-acid meat and vegetable fibers … where they’re even harder to kill–can live through 212 degrees with no problem. They consider boiling water just a nice trip to the hot tub. They splash around, they invite friends over for e-coli cocktails, and just generally hang out–waiting to make you sick–so you have to get those canning cooties up to around 240 degrees. Then you have to keep them there for a specified amount of time in order to be sure you’ve killed them completely.

That’s why a Pressure Canner is a critical piece of canning gear for any serious canner. As I discussed in my canning overview, you simply cannot sterilize or safely can certain foods without one.

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What do you look for in a good Pressure Canner?

Well, you’re in luck! There really aren’t that many players in the world of Pressure Canners: not in the styles available to the home canner, or in the companies who make them. Basically, there are weight-gauge canners and dial-gauge canners … and–in my opinion–there are really only two American companies who makes ones worth buying: Presto and All-American.

A dial-gauge Pressure Canner is exactly what it sounds like: it’s a Pressure Canner that uses a dial gauge–screwed into a small hole in the lid–to tell you how much pressure has built up inside your pot. Most recipes require you to process your food and jars at 6psi, 11psi, or 16psi (depending on the type of food and your current elevation), and the dial gauge makes it very easy to read the exact pressure in your pot. Adjusting the heat and pressure in the pot is also simple. If the pressure is too low, turn up the heat. If the pressure is too high, turn the heat back down or remove the pot from the heat source temporarily, not returning it to the burner until the temperature and pressure drop back down to the level you need.

In most versions, a dial-gauge canner has two more holes in the lid as well, in addition to the one blocked by the dial gauge. First, it has a vent pipe: a roughly two inch piece of hollow pipe, capped with a loose, one-piece weight. This vent and weight combination is a safety device, designed to help bleed off and regulate pressure in the pot if it gets too high. A Pressure Canner should never go over about 18-20psi total. That’s pushing into dangerous territory. It’s pressures over 20psi that caused many of the horror stories you’ve heard about pressure cookers exploding, so the weigh is designed to hold pressure inside the pot by using it’s own weight on the top of the vent pipe. It’s also designed to start wobbling if the pressure climbs over that point, rocking back and forth and venting some of the extra pressure safely. From there, it’s common sense. The more pressure … the more wobble. The more wobble … the more venting. The more venting … the lower the pressure in the pot.

There’s also an emergency hole in the middle of the lid, usually filled with some sort of rubber (or combined rubber and metal) plug. It’s designed to blow out completely (catastrophically, as a last fail safe) if the pressure gets too high inside the pot, despite the vent stem/weight pressure bleeding system. If the final fail-safe blows, it opens a 1/2 to 3/4 inch hole in the top of the lid … effectively and instantly dropping the pressure in the pot to normal air pressure. Problem solved. Of course, there’s the issue of dealing with how far the rubber and metal plug flies … what it hits … and what sort of glass and food might fly out of the pot with it

Similarly, a weight-gauge Pressure Canner also uses that same center emergency blow-out plug as a last resort/fail safe against the pressure getting too high inside the pot. However, this second type of canner has only one other hole in the lid: one filled by the same sort of vent pipe as I mentioned in the dial-gauge version. Instead of using a dial gauge to express the level of pressure in the canner, or a one-piece weight on top of the vent pipe as a safety device, a weight-gauge Pressure Canner uses a stack of variable weights sitting atop that same vent pipe to also regulate the pressure inside the pot, much like the emergency overflow vent pipe/weight combo used in the dial-gauge canner. The weight gauge also, in effect, measures the pressure in the pot, too … by indicating roughly how much pressure is in the pot at any given time by its motion.

The typical weight-gauge design incorporates a base–which, when used alone, would register 5psi–with two additional weights that can be added on: one creating a 10psi weight, and–with both weights installed–a 15psi weight.

How the weight gauge works is simple mechanics. Just like the one-part safety weight on the dial-gauge canner, the multi-part weight-gauge sits atop the vent pipe and blocks the exit hole, basically holding the pressure in the pot by virtue of its own weight. Then, once the pressure goes over 5, 10, or 15psi (depending on how you have your weight-gauge configured), that weight gauge begins to rock against the top of the vent pipe, releasing some of the pressure that’s built up inside the pot. The faster the weight gauge rocks, the more pressure there is inside the pot … trying to get out.

Generally, most manufacturers recommend you start a weight-gauge Pressure Canner off on the highest temperature possible … then, once the wobble starts, adjust the heat down from there, until you’ve achieved a state where you have consistent wobble … just not an extreme or excessive wobble. And you adjust that pressure the same way you do with a dial-gauge pot. If the pressure is too high (i.e.: you’re getting too much bobble), turn the heat under the pot down. If the pressure is too low (i.e.: you’re not getting enough wobble), turn it up instead. Some owners manuals say that a consistent, steady wiggle is the correct indication of good pressure. Others say you only need a wobble or two a minute to know you’re at proper pressure inside the pot. Read your specific canner’s instruction manual for their exact recommendations for wiggle/wobble/bobble/whatever you end up calling it.

Now … which kind of gauge is better?

The answer to that question really depends on YOU, on what YOU plan to do with your Pressure Canner, and on which style pot works better for your canning work style.

The #1 benefit of a dial-gauge pot is accuracy. That dial tells you exactly what’s going on inside your pot–right down to single pounds of pressure. That sort of precision can be helpful when you’re trying to save every scrap of texture you can manage in delicate foods. Some foods can become very, very soft in a normal canning cycle … so over-processing them even a tiny amount can turn them into complete mush. The precision of a dial-gauge pot can help you make sure that you process your foods the absolute safe minimum amount of time/pressure … without taking it one foot-pound or second further.

The #1 down side of a dial-gauge pot is … they’re REALLY tough to regulate sometimes. You turn it down … and it gets too low too fast. You turn it up … and suddenly it’s way, WAY too high again. And then you finally get it set just so …. but then ten minutes later–when you haven’t touched a single-blasted-thing–you look again … and it’s suddenly way too high again! GRR!! And–of course–every canner load is different, based on how many jars, what’s in the jars, etc., etc., so you really can’t use the process you discovered on the last canner load … and duplicate it reliably and consistently with this canner load. You just have to get a feel for it.

Worse, if you let that canner drop below pressure at ANY point in your canning process/timing … you have to get it back up to pressure … and then you have to start the timer all over again from the very beginning, even if you were only a minute or two away from the bell before you lost pressure.

WHY!?!?! you ask in horror …

It’s simple: you can’t be sure you killed all the canning cooties unless you process your food for at least x-minutes STRAIGHT at x-psi. It works because of a combination of both heat AND duration, so it’s not something you can break up into chunks. And–needless to say–if you let the pressure get too low just once … and you have to start your timer over completely because of it … it completely wipes out anything you saved texture-wise by choosing a dial-gauge canner. It’s enough to make you bang your head on your kitchen cabinets!

In contrast, the #1 benefit of a weight-gauge canner is ease of use. You don’t have to watch that style like a hawk–not like you have to watch a dial gauge–because you can hear that weight wobbling from across the room, or even from another room. That easy audible signal tells you that you’ve reached pressure … or that you continue to maintain it. Plus–as I said, short of just foolishly turning the burner on high and walking way for an hour or two–once you’ve brought a weight-gauge canner up to pressure and then cut your heat back to something more reasonable, a weight-gauge canner is mostly self-regulating. The design of the gauge makes it vent excess pressure for you–a little bit, each and every time it wobbles–so there’s far less of a chance that your pot is going to inadvertently paint your ceiling with Beef Stew or Chicken Soup. Not like that dial-gauge pot may do (and QUICKLY!) if you don’t pay close attention to that what that dial says!

And the #1 down-side of a weight-gauge canner is inaccuracy. Sure, it’s the workhorse of Pressure Canners, and it cans in large swaths–cutting across a wide variety of foods and canning styles–but when the weight-gauge says it’s “10psi” … you’re probably dealing with a somewhat more heat and temperature right at that moment than a simple “10psi.” Why? Because all that weight gauge can really tell you is … if I’m jiggling, it means that I’ve got at least X-amount of pressure inside this pot (based on how you have the weights stacked), else … I couldn’t be making this weight move. The reality is … the pressure in your pot could be a lot higher than 10psi … and that inaccuracy can affect the resulting textures of your more delicate foods.

Which type canner do I have in my own kitchen? That’s easy: both! I actually own three different Pressure Canners–a 16-quart and a 21-quart weight-gauge model, and a 16-quart dial-gauge pot.

Why do I have all three? Because–that way–I can use more than one at a time, running them in tandem. That’s useful for processing big batches of food. I can have one heating up while another is spinning down. Besides, sometimes each one is the exact right tool for that exact situation.

Which one do I reach for most often? That’s easy! My 16-quart weight-gauge canner. It’s my #1 workhorse, hands down!

As far as brands go, I know that a few other companies make Pressure Canners: Faygor, Mirro, and T-Fal in particular. However–unless they’ve come out with a model that I haven’t seen yet (which is definitely possible: I don’t claim to be perfect, and I don’t spend all my time researching pots either)–all of them say they’re weight-gauge Pressure Canners … but none of them have the three-part weights I discussed earlier, which gives you a wider variety of control than those one-piece weight gauges do. The one-piece weight-gauge pots process at one pressure, period. And–often–they never really tell you exactly what that pressure is either … no matter how deep you dig into their paperwork. The small Faygor I bought (and used once) is a prime example. The safety blow-out plug melted after one use, and I still don’t know what psi it runs at. Therefore … I don’t personally recommend them for Pressure Canning. They’re even more inaccurate than regular weight-gauge canners, and they don’t have nearly the range of pressures you need to can various foods at various elevations.

That leaves you with the two brands I tend to recommended: Presto and All-American.

National Presto began in Eau Claire, WI in 1905, manufacturing pressure canning equipment for the commercial canning industry. They expanded their line to include home-canning equipment in 1915, and they remain the #1 Pressure Canner manufacturer in the United States to this day.

PPCs are very well-made, plus they’ve only had a couple of design overhauls on their products over the years … so pots spanning several years or even decades all use the same readily-available replacement parts: a major reason why many of Presto’s older models are still on the road today. I own two myself that I bought second-hand, both dial-gauge canners. One’s a 50s vintage, 16-quart. I paid $12.50 for it at a thrift store. The other is a 70s model, 21-quart, that I subsequently converted to a weight-gauge canner…which I’ll post about separately one day! I bought it at a yard sale for $25.00. Despite the difference in their ages and their sizes, they use the exact same gaskets and replacement parts.

The #1 benefit of a Presto Pressure Canner is cost and availability. In addition to all the other places you can buy them for about the same price (including at Amazon.com … were they qualify for free shipping: you don’t even have to leave your house to get one, they’ll bring it to you!)–you can buy a 16-quart PPC for <$70.00 at pretty much any Walmart in pretty much any town in the U.S. As I said, I own two I found second-hand … and, even after buying new gaskets for both and a replacement gauge for one of the pair, I still have less in both of them than I paid for the one I bought new. Replacement gaskets are cheap. They run $8-20, depending on the model, and–if your dial gauge is broken, replacements run about $20 for that, too. Lose your three-part weight-gauge? No problem: $8.00. Some of the parts are readily available at your local Ace Hardware, or you can order any of them online, directly from Presto. They definitely make it easy to get parts … and to keep your PPC running over the decades!

The #1 down-side of a Presto Pressure Canner is having to replace the gaskets. Given their recommendations–and considering how often I use my canner–I feel like I should probably replace my gaskets every six to nine months. It helps that I have two canners that can share parts (so–in an emergency–I can mix and match between them), but I feel like I’m always stressing the rubber parts of my canners. Plus, in the event of a regional or national emergency … where the availability of resources suddenly got precious … rubber gaskets for Pressure Canners may be worth more than gold itself.

By comparison, All-American Pressure Canner represent the apex of modern canner science. Since the company began in the 30s, they’ve taken the basic Pressure Canner design and polished it over the years to a fine sheen. They’re sleek. They’re modern. And they don’t use rubber gaskets, either … which puts them head and shoulders above the competition. Instead, All-American canners use a series of screw-down locks in the lid and a patented metal-on-metal sealing system. They only sell dial-gauge canners–which some may see as a down-side–but their dial gauges are definitely top of the line. And, bonus points, they sell a far larger selection of pot sizes than any other Pressure Canner manufacturer in the world … from 10.5 quarts … all the way up to 41.5 quarts … including pots big enough to allow you to stack quart jars inside them, doubling your capacity per load! AA’s are–hands down–the favorites of hard-core canners.

The #1 benefit of an All-American canner is the fact that it doesn’t rely on rubber gaskets. You don’t have to keep checking them. You don’t have to buy them. You don’t have to replace them. Even in the event of the apocalypse … you’ll still be canning … when alllllllll the other Presto owners are trying to figure out how to cut down old rubber car tires to make replacement gaskets for their busted old Pressure Canners. I’m sure you’ll REALLY need your canner at that point, too. It will probably be worth more than a car in that world … and an All-American is definitely a Cadillac.

The #1 draw-back of an All-American canner is PRICE! Comparing straight Amazon.com price to Amazon.com price, a 16-quart Presto costs $71.99 … and a 15.5-quart All-American costs a whopping $179.99. Good grief! You do the math And it gets worse from there. Like the look of that 41.5 quart size? It retails for $464.03. Yes, you do save some money by not having to buy new rubber gaskets each year  … but how many rubber gaskets/years would it take to make up a $108.00 difference at your house? Or a bigger one? Plus, that $108.oo difference is for a new pot. Imagine how much money you’d save if you found a used Presto for cheap like I did … twice. Even if you did have to buy a new rubber gasket and/or dial gauge for it periodically, it’s still a LOT CHEAPER than buying an AA.

Bottom line … the choice, as always, is yours. I just presented you with my observations. It’s up to you to look at your life, your canning habits, and your budget … to decide for yourself. Personally, I still want an All-American, too … but I keep holding out, and hoping I’ll find one at a yard sale or thrift store one day. If I could find a decent-sized one somewhere for less than $100–I’ll buy it in a flash!

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How do you use a Pressure Canner, and how is it different from working with a BWB canner?

First and foremost, you do need to treat your flat, rubber gasketed jar lids in 180 degree water for a few minutes before you use them, just to get the rubber tacky enough that it makes a good seal … but, beyond that, you don’t necessarily need to sterilize your jars in advance when you’re going to use your Pressure Canner, not like the 15-minutes in boiling water process I described when you use a BWB. The inside of a Pressure Canner reaches temperatures in excess of 240 degrees, which can easily and thoroughly sterilize your jars and food during the canning process … inside and out … without you having to take extraordinary measures elsewhere.

A good, basic washing with soapy water–followed by a rinse with clear water–is usually sufficient to get your jars ready to be filled for the Pressure Canner. Just be sure to keep your jars warm until you fill them with your warm food … so that you don’t end up with cracked jars. Abrupt temperature shifts can be brutal on glass, especially inside a Pressure Canner. Don’t put hot food into cold jars or cold jars into a hot canner! That’s just asking for broken glass and food everywhere. To solve this problem, some people (like me) wash their jars in their dishwasher and then keep them warm there until they’re ready for them. My drying cycle runs for upwards of 30 minutes, which is plenty of time to fill a couple of dozen jars once the wash cycle ends. Others wash their jars by hand and then let them dry/stay warm in a 250 degree oven until they’re ready for them. Choose which one suits you/your kitchen best.

Once your jars are prepped, you need to be absolutely sure you maintain proper headspace when you fill them with food. It’s important in a BWB canner, but it’s even more vitally important in a Pressure Canner, where the combination of heat and pressure can make the food in your jar expand drastically in size. The liquids in your jars boil, too. In fact, you’ll discover on your first batch that the liquids in your jars can often boil for HOURS … right there on your counter, long after you remove your jars out of a cooled Pressure Canner. That shows you just how hot it really gets inside those jars, thanks to the addition of pressure! That also explains why headspace recommendations tend to run a lot deeper for Pressure Canner jars than they do for BWB jars. You can fill jam jars destined for a BWB to within a quarter inch of the lip … because jam doesn’t really grow in the jar when you heat it. It pretty much stays the same size/shape. But if you’re canning carrots in water in a Pressure Canner … you’d better respect that one-inch headspace requirement … or your carrots may crawl right out of the jar on you. Plus, all that boiling keeps the food agitated in the jar for extended periods of time … and all it takes is one small particle of food lodging itself between the rubber gasket on your lid and the glass lip of your jar to ruin your seal. Sometimes your lids just don’t seal at all. We’ve all pulled a jar out of the Pressure Canner, and found a great big hunk of food stuck in the seal. Worse, smaller chunks of food (even microscopic ones) can make for a weak seal, too: one that looks solid in the beginning, but then it opens itself in your pantry one day when you’re least expecting it.

So let me say it again: respect headspace!

Beyond that, the rules for Pressure Canners are fairly simple, but–as I’ve said before–be sure to read the book that comes with your particular Pressure Canner model … just in case your pot has a particular quirk you need to be aware of.

As a general rule, you should always start out with hot-to-boiling water (depending on how hot the food is that you’re putting in your jars), either filled to the line indicated in the bottom of the pot … or–if your pot’s old enough to be lineless–to roughly 2-3″inches. In other words, rather than covering your jars with 2″inches of water (like, in a BWB canner) … your Pressure Canner jars are just going to be sitting in a couple of inches of water … but that’s okay. There will be steam and pressure aplenty inside the pot shortly, and they will combine to accomplish the rest.

You should fill your jars and put lids on them in much the same way as you did with your BWB canner, making sure to work all the air bubbles out before you clean the lip and screw the two-part lid on. Air bubbles can cause hot/cold spots in your jars–especially in a Pressure Canner–so be sure to get rid of them all. I’ve found that a chopstick works great, and they’re a lot cheaper than the dedicated air-bubble tools they constantly try to sell you! Once you have all the jars filled and loaded into the Pressure Canner, twist on the lid and start the heat underneath.

If you’re using a dial-gauge pot, your gauge should be intact when you turn on the heat, but you want to keep the one-part weight (the safety weight that sits on the overflow valve stem) off for the time being. If you’re using a weight-gauge pot, then don’t put the weight on the stem yet either.

Yes, that means that you’re basically leaving each type pot open for now … but this is a very important step. You see, as you loaded your Pressure Canner with jars of food, you basically combined several different elements into the same space … elements that–right at that moment–are all at different temperatures. Your pot is sitting at one temp, thanks to the hot/boiling water you put in it to get started. Its lid is probably several degrees cooler, since it didn’t get exposed to hot water when the pot did. And then each jar–even though you pulled it out of wherever you were keeping it warm and then filled it with warm/hot food–is going to have a slightly different temperature, too, based on how long it took you to fill it, etc., etc., etc. If you just toss those jars in, crank up the heat, and seal the pot right off the bat … you run the risk of breaking jars … or not processing your food hot/long enough to sterilize/preserve it properly, simply because the heat doesn’t have a chance to get all the way through the jar and the food. Both are problematic … therefore, always remember to vent your pot first.

To properly vent your Pressure Canner … fill it with jars (remember: ALWAYS be sure that you put a metal rack in the bottom of your pot first–just like with a BWB canner–so that your jars don’t actually touch the metal bottom of the pot) … then twist on the lid, turn on the heat, and keep an eye on the pot until you see steam coming out of the open vent pipe. Once you have a solid, steady column of steam hissssing out of the top of the vent pipe–an indication that the water inside has reached the boiling point–set your timer for ten minutes, and just let it run on high and vent that entire time.

If you’re interested in the science behind it, what you’re basically doing during this ten minutes is bringing everything inside the pot–and the pot itself–all up to the same temperature. This is vitally important, since–if you try to pressurize that pot while you have things inside it at different temperatures–you could easily break jars.

At the end of the ten minutes, put either the one-part safety weight (if you’re using a dial-gauge canner), or the variable weight-gauge (set to the right weight for this batch) on the top of your valve stem, blocking the last open exit from the pot.

With that last hole closed, it shouldn’t take more than 5-10 minutes from there for your pot to reach the proper pressure. You’ll know you’ve reached it when either your dial-gauge reads the right number (6, 11, 16) … or when your weight-gauge starts to bobble. When you reach proper pressure, start to adjust the heat downwards from there. How far down is very dependent on the pot, the stove, or even strange things like the pressure of your gas or how many watts you actually having coming thought your AC current. After you’ve done it a few times, you’ll begin to get a feel for where to set your burner in the first heat reduction. Experiment until you find the absolute lowest heat setting … one that will keep your pressure up and constant, but no more. Once you find that sweet spot–where your dial-gauge is steady on the right pressure … or your weight-gauge is bobbling happily and at the correct rate–THEN start your timer for the number of minutes you need to process that particular batch.

Be aware: as the processing time goes along, it’s not uncommon for your pressure to start climbing again at some point, maybe 3/4ths of the way through your canning cycle … so keep an eye on your pot/gauge. It doesn’t usually shift upwards very far … but it can, and–when it does–it can make a difference … so you need to be aware of the phenom. If your pressure/temperature starts up-shifting too much, turn your heat down slightly … but go slow with those adjustments! Don’t try to drop it too low too fast. Remember, if you let pressure drop even one psi below the required pressure, then you’ve disrupted the canning cycle. If that happens, then you have to bring your Pressure Canner back up to the proper pressure … and then you have to start your timer all over again from the very beginning. Why? Because it takes a certain amount of heat over a certain duration of time in order to kill canning cooties. If you don’t get the entire duration–in one block–then you could risk not killing some of the more vicious canning cooties. That would be bad. And, I don’t know about you … but I shudder at the thought of having to almost double-process some of the more delicate foods I run through my Pressure Canner … so I adjust my heat conservatively, and wait to see how each adjustment is going to work before I dare do another one. Don’t be afraid of this problem, however. It make take a couple of times for you to get a real feel for it, but you will

Once your timer goes off, indicating that you’ve reached the end of your required canning cycle, turn off the heat, and allow the pot to cool naturally. DO NOT try to hurry that cooling along! I’ve heard of all sorts of tricks that people have tried to use to cool a Pressure Canner faster: putting cool water or ice on the outside, putting the pot in front of a fan on HIGH, bumping the weight-gauge, trying to release a bit of pressure, others. DON’T DO IT! Cooling jars too fast when they’re under pressure can cause the same problems that trying to heat them up too fast can cause: namely, broken jars or hot/cold spots … so don’t try to short-change the process. Let it take its natural course. It usually only takes a half-hour or so for your heat and pressure to drop enough that you can open the pot. Watch a sit-com ‘-)

Once the pressure drops in your pot, unscrew the lid and–carefully–remove your hot jars from the canner. Set them on a flat surface–protected by an absorbent towel, and out of the way of any drafts–and allow them to continue to cool naturally. Once they’ve reached room temperature, check your seals carefully on each lid. Mark and shelve the ones that sealed properly, and refrigerate any unsealed jars to either eat or reprocess at some point later.

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Let’s recap:

• There are two different types of Pressure Canners: dial-gauge and weight-gauge. And there are two different brands I recommend: Presto and All-American. Pick the one that works for you … or, be like me, and have a couple of different versions on hand. They give you the variety to process different types of food, and the ability to process multiple batches more time-efficiently by running more than one canner in tandem.

• Read the manual for your particular Pressure Canner! Make sure you know how it works before you start trying to use it.

• Unlike a BWB canner, you don’t have to boil/sterilize your jars in advance with a Pressure Canner. Just start with clean, warm jars. You do, however, need to heat your rubber-gasketed flat lids up to 180 degrees–just like you do in a BWB batch–in order to heat the rubber enough to make a good seal against the lip of the jar.

• Respect headspace requirements for the food you’re canning! Remember, inside the heat and pressure of a Pressure Canner, foods expand and liquids boil. Leave them enough room to do that comfortably, or you and your seals will regret it.

• Be sure to vent your pot before you seal it completely! Load it full of jars, screw on the lid, and put it on high heat. Do not put the one-piece safety weight or three-part weight-gauge on the vent pipe yet! Leave the pot open at first! Once there’s steam coming out of the vent pipe in a steady hiss, set a timer for ten minutes. Once the timer goes off … THEN seal the pot by adding the appropriate weight on top of the vent pipe.

• Always bring a Pressure Canner up to heat/pressure on HIGH, and then adjust the heat downward until you find the correct temperature that keeps your dial gauge at the right pressure … or your weight gauge bobbling at the correct rate.

• Remember: if your pressure drops below the required level at ANY point during the timed canning process, you must bring the heat/pressure back up … and then set your timer back to the beginning … and start it allllllllll over again. Canning times must be uninterrupted. You can’t just pick it up in the middle someplace.

I’m sure I’ll think of more from there, gang … and continue to refine my observations from there. Stay tuned for updates