In my my time on Yahoo groups dedicated to the canning arts, I’ve noticed a trend. Canner manufacturers give BAD advice 😯
What do I mean by that? Okay, here’s what it says in the All American Pressure Canner manuals about starting up a canner: Pour 1-1/2 inches of water into the pot … Place lid on cooker [sic], place pressure cooker over heat source on high heat and allow steam to escape from the Vent Pipe for 7 minutes before placing the selective Pressure Regulator Weight on Vent Pipe.
Then here’s what the Presto manual says: Place 3 quarts of boiling water, canning rack, and jars in canner … Using a relatively high heat setting, heat the pressure canner until a steady flow of steam can be seen, heard, or felt coming from the vent pipe. Exhaust air from the canner for 10 minutes by allowing steam to flow from the vent pipe. Reduce heat, if necessary, to maintain a steady, moderate flow of steam.
So … what’s the problem with this advice?
Well, first off … it’s vague … but the biggest problem is … if you’re canning boiling hot food in pre-heated jars, then there’s not a single thing wrong with that advice. Use it, and your jars will come out perfect every time.
The problem is … a lot of the things we set out to can aren’t necessarily going into the jar boiling hot. We raw-pack all sorts of foods as a matter of course these days, and–more and more, just like other canners–I’m doing more in the way of “cooked in the jar” sorts of foods myself … convenience foods created by combining raw and cooked foods, many that go into the jar at various temperatures. And when you’re starting out with less than boiling hot food instead … all that boiling hot water and start it out on HIGH stuff is really bad advice.
Why? you ask. Because–if you put cold food in jars … put them into a canner with 1.5 inches of boiling hot water … turn the heat on HIGH … that water can boil around those jars a lot faster than the food in the jars will heat up. This is especially prevalent at the higher elevations (where water boils at lower temperatures) but it can happen at dead sea level, too. In fact–in some cases–you can get 10 minutes worth of “steam” out of the top of the vent pipe (more on that in a second) … then seal the pot … yet, the food in the middle of your jars may STILL not be up to full temperature at that point. And if you seal the pot before the food in the jars is up to the same temperature as the water/pot … then you run the risk of broken jars … or–at least–of jars venting food right along with the steam, which could cause seal failures … both immediately … and later, too, after those jars have sat on your shelf a couple of months, and the microscopic food particles stuck between the rubber gasket and the glass lip of your canning jar start to rot.
So, how do you prevent all this uneven heating from ruining your canning batch?
The trick to even heating in your pressure canner is two-fold: one, start everything at approximately the same temperature … and two, TAKE YOUR TIME! When most people describe their seal failures/blown jars full of food to me, the #1 reason I’ve seen for failure is that they either tried to rush or shortcut the canning process … or, unfortunately, they tried to follow that boiling hot water/start it on HIGH advice from the canner manuals. It’s frustrating to keep ending up with broken jars, or jars that lose a large percentage of their contents in the canner … only to have the seal–that you thought was okay, despite the blow-out–come back and fail six months later … in the back of your cabinet … where your nose finds it before your eyes do 😮
On the flip side of that experience, I’ve just spent the last few days canning a bunch of meals for my husband, in preparation to go on the road again soon (more later :)) … so–since Wednesday–I’ve canned the following items, all of them “cooked in the jar” and created by combining different temperatures of food together, to create a jar that’s no where near full of boiling hot food when it goes in the canner. I made:
- 16 pints of ham and bean soup,
- 16 pints of sausage stew,
- 30 pints of beef vegetable soup, and
- 14 pints of hot wings.
How many of those 76 jars failed to seal?
I didn’t lose a single jar … because I’ve figured out how to start everything at the same temperature … and how to take my time
Here’s the sequence I use. I won’t claim it has a 100% success rate, but it’s currently sitting at a solid 99.5% rate for me:
- fill your canner to the proper depth (3 quarts, up to the line, whatever your canner recommends) with water that’s approx. the same temperature of the food you’re going to can. This means if you’re canning cold, raw-packed food, you start with cold water. If you’re canning a mix of raw-pack and hot-pack foods, you should start with warm water. And, as the canner manufacturers recommend, if you’re canning boiling hot food, then start with boiling hot water.
- load the pot with properly-prepared jars of food, whatever that means for your recipe.
- put the top on your pot, but do NOT put the weight on the vent stem yet.
- if you started with something other than boiling hot food poured into hot jars, then start your pot on medium or medium-high. If you start with boiling hot food, boiling hot jars, and boiling hot water … then you should start the canner on HIGH … and skip straight to #6 when it boils inside the canner.
- once you turn the heat on under your pot … you need to wait–sometimes 20-30 minutes (or more) depending on how hot/cold it was to start with–until the steam is beginning to rush out of the vent pipe in a solid stream …
- … then–once it hits that boiling point–THEN turn your pot on HIGH … and let it boil HARD like that for another 3-4 minutes more, just to be sure … BEFORE you start your 10-minute timer. Don’t start it until being on HIGH has the steam running like gangbusters. How do you know it’s time to start the timer? The steam should be coming out of the vent pipe at this point so HOT/FAST that you can’t hold your hand over the top of it (within 1-2″) for any length of time … and it should have been running at MAX like that for at least 3-4 minutes BEFORE you start your 10-minute vent timer, just so you can be sure you’re getting a solid “Old Faithful” kinda steam jet FIRST, before you set that 10 minute timer to vent your canner. And–yes–I know that AA suggests seven minutes. I don’t have one … so I can’t speak for how fast/evenly it heats up … but when I eventually get one, I’ll probably still vent it 10 minutes … just to be extra sure. Like I said: take your time.
- once that 10-minute timer goes off, put the weight on the top of the vent stem–set to either 5, 10, or 15PSI … or the one-part weight on a dial canner–and leave the pot on HIGH until either the weight starts to jiggle, or the pressure on that gauge reaches the level you need.
- once the weight starts to jiggle/your gauge reaches the proper pressure, start your ‘canning cycle duration’ timer (based on your elevation, and the recommendations on the type of food from the NCHFP) and then turn the heat down slowly, to the point that the burner heat maintains the appropriate jiggle, based on your canner manufacturer, or the dial maintains the appropriate pressure, based on the NCHFP recommendations. REMEMBER, if you turn the heat down too fast … and either the jiggle stops, or the pressure drops below the recommended level … EVEN FOR A MINUTE! …then you’re going to have to bring the pot back up to temperature … and then start that timer over from the very beginning again … else, you can’t be guaranteed that your food’s safe … since it takes a certain level of heat held for a certain DURATION to be safe. And if you miss that duration by as little as one minute … you need to start that timer allllll over again to be safe.
Finally, the #1 problem with the vague language in most canner manuals is that they can’t show you what I can show you here with video. So, if you’ve ever wondered what a canner looks like when it’s ready for you to start the timer … and to vent your canner for 10 minutes … then this is it. I put an old cork board behind the column of steam to help you see it better … but what I really want you to do is turn on your speakers … and listen to this column of steam while you look at it. This is what you’re shooting for:
If it doesn’t look like that … then you’re not ready to start your timer for the vent cycle yet.