Questions: Getting the pressure right

[Cedar]

Hello!

I've been canning for about one year now, mostly water bath, but some pressure canning. I've been wondering about the best way to adjust the pressure on my Mirro canner with the metal weight gauge.

I played around with my canner early on, so I know the EXACT spot on my stove where I can get the gauge to "jiggle" 3 to 4 times per minute (as per the Mirro instructions).

My question is, what is the best way to get to that spot after letting the canner do its venting for 10 minutes? Should I turn the temp down in increments slowly going to that "spot"? Or do I turn it all the way down to the "special temp" on the stove dial and then wait until pressure eventually builds back up and starts the gauge to jiggle the right amount of times?

My experience so far has been that if I turn it down to that exact spot, it seems to never get the pressure back up to where it jiggles again (although I've never waited long enough to really find out....it just took so long, I worried something might be wrong so turned it back up).

OR if I just turn it down in increments, I lose a lot of the water in my jars because of the pressure changes.

Also to anyone who has the pressure canner with the metal weight gauge, when it says that it should jiggle "3 to 4 times per minute" what does a full jiggle mean exactly? Sometimes it just does a really short 2 second jiggle...other times it will last several seconds. IOW how long does a jiggle have to be to fully count?

[JarDude]

Originally Posted by Cedar

Hello!

I've been canning for about one year now, mostly water bath, but some pressure canning. I've been wondering about the best way to adjust the pressure on my Mirro canner with the metal weight gauge.

I played around with my canner early on, so I know the EXACT spot on my stove where I can get the gauge to "jiggle" 3 to 4 times per minute (as per the Mirro instructions).

My question is, what is the best way to get to that spot after letting the canner do its venting for 10 minutes? Should I turn the temp down in increments slowly going to that "spot"? Or do I turn it all the way down to the "special temp" on the stove dial and then wait until pressure eventually builds back up and starts the gauge to jiggle the right amount of times?

My experience so far has been that if I turn it down to that exact spot, it seems to never get the pressure back up to where it jiggles again (although I've never waited long enough to really find out....it just took so long, I worried something might be wrong so turned it back up).

OR if I just turn it down in increments, I lose a lot of the water in my jars because of the pressure changes.

Also to anyone who has the pressure canner with the metal weight gauge, when it says that it should jiggle "3 to 4 times per minute" what does a full jiggle mean exactly? Sometimes it just does a really short 2 second jiggle...other times it will last several seconds. IOW how long does a jiggle have to be to fully count?

IMO you have to turn it down incrementally and that isn't what causes you to lose water from the jars because there is no more pressure change. The pressure doesn't get above 10 pounds. If you have difficulty "calming" it down then you may be starting with the heat to high. I found this out when I started using a smaller 8 quart canner. If I left the heat on full high like I do with the larger canners then i would have a real tough time getting it to settle down into a regular rhythm.

If the weight jiggles, it's a jiggle. Doesn't matter if it is one second or ten.

I have discussed the 3-4 times a moinute with many. I don't understand the difference between one time per minute and 4. The pressure ois the same either way.

[grumble]

I don't can, so take this FWIW.

The pressure inside the canner really doesn't matter, it's the temperature that matters. The higher the pressure, the higher the temp at which water boils. The idea is to use the minimum heat for a designated length of time to cook and sterilize the contents of the jars.

If the jiggler jiggles too fast, you're just wasting heat. And, the steam bubbles are a lot hotter than the water, and can transfer heat to the jars, overcooking the contents. A physicist will argue that no matter how fast you boil water, it will still only be at its boiling temperature. But, as a cook will tell you, a fast boil will cook potatoes faster than a slow boil -- the water temp is the same, but the steam bubbles add heat to the taters.

[Cedar]

Originally Posted by JarDude

IMO you have to turn it down incrementally and that isn't what causes you to lose water from the jars because there is no more pressure change. The pressure doesn't get above 10 pounds. If you have difficulty "calming" it down then you may be starting with the heat to high. I found this out when I started using a smaller 8 quart canner. If I left the heat on full high like I do with the larger canners then i would have a real tough time getting it to settle down into a regular rhythm.

If the weight jiggles, it's a jiggle. Doesn't matter if it is one second or ten.

I have discussed the 3-4 times a moinute with many. I don't understand the difference between one time per minute and 4. The pressure ois the same either way.

Thank you for your input.

As far as starting with the heat too high, I was following what the manual said to let it vent for 10 minutes "on high." High on my stove is 10. I recently found that if I put it on 7 or 8, it vented just as well, but I only tried it once being concerned I wasn't going by the book.

So just to make sure I understand correctly, this is what you mean, that it's ok to let it vent on a lower temperature setting (med high, or whatever)?

[NCLee]

This is something that aggravates me about canning manuals.

High on one stove is medium heat on another. It depends on the BTU rating of the burner being used under the canner.

Start your canner out on HIGH to heat the water quickly. When steam begins to come out of the vent, turn down the heat to the where it will give you a steady flow of steam for the 10 minutes. A good steady flow is all you need. If your canner sounds like an old fashioned train steam engine releasing steam, your heat is too high.

From a stove dial standpoint, sometimes it would be better if the dial didn't have numbers or other indicators. Just rotate the dial to the position that gives the desired result, regardless of what the graphics indicate.

I had a gas stove one time where HIGH was pitiful. Replaced it with one with a high output burner. That burner on HIGH would empty my canner of water if I used it for canning. It would sound like a run-away steam engine.

Lee

[Cedar]

Thanks, Lee, for this clarification. The steam train analogy is a good one. I understand and I feel more confident to use my pressure canner now.

[saigo]

This is really good info, I have a metal weight canner too, and have often wondered the same thing.