Canning pressure question

[k15n1]

" I know every time the pressure dips below 11 lbs, I have to start my timing over. That's fine, I get that. "


Where did you read this? Just wondering.

gina

This is standard practice. A second or two below pressure may not matter, but I've found that the time required to change the pressure/temperature is usually significant. If pressure drops below 10 psi and it takes you 5 minutes to get it back, it'll probably have an effect on the heat transfer into the food. The other reason is that the USDA testing used that protocol. They've shown 1 way to be safe. Deviations from that method haven't been tested. There may be deviations from the method that are not a problem, but they're not tested. Also, after a batch or 2, you'll get the hang of it and there'll be no need to think/worry about pressure drops.

BTW, if you have a sudden pressure drop, you may have run out of water. In my aluminum retort, that would be a disaster. Even if you have a stainless Presto or something, running it dry is a problem. The pan will warp, perhaps permanently, and laminates can separate. If you have a stainless pot, chances are that it has an aluminum core because that distributes the heat better than stainless.

 

[cheepo]

congratulations...on your first can...!!!
i used to have your problem...a lot with my first old presto...when i finally upgraded to an all american...
it stays...perfectly waited...and i don't have to constantly whatch the guage anymore...
just makes it a tad easier...

 

[cheepo]

congratulations...on your first can...!!!
i used to have your problem...a lot with my first old presto...when i finally upgraded to an all american...
it stays...perfectly waited...and i don't have to constantly whatch the guage anymore...
just makes it a tad easier...

 

[Corn Woman]

The recommended pressure for my altitude is 12 lbs pressure, but I have a weighted gauge on my canner so I can only choose 10lbs or 15 lbs, so I can everything at 15lbs pressure, no problems whatsoever

Same for me weighted gauge and everything gets 15 lbs except for green beans. I tried 15lbs and didn't like the result so I use 10 lbs and extra time.

 

[TanksHill]

" I know every time the pressure dips below 11 lbs, I have to start my timing over. That's fine, I get that. "


Where did you read this? Just wondering.

gina

This is standard practice. A second or two below pressure may not matter, but I've found that the time required to change the pressure/temperature is usually significant. If pressure drops below 10 psi and it takes you 5 minutes to get it back, it'll probably have an effect on the heat transfer into the food. The other reason is that the USDA testing used that protocol. They've shown 1 way to be safe. Deviations from that method haven't been tested. There may be deviations from the method that are not a problem, but they're not tested. Also, after a batch or 2, you'll get the hang of it and there'll be no need to think/worry about pressure drops.

BTW, if you have a sudden pressure drop, you may have run out of water. In my aluminum retort, that would be a disaster. Even if you have a stainless Presto or something, running it dry is a problem. The pan will warp, perhaps permanently, and laminates can separate. If you have a stainless pot, chances are that it has an aluminum core because that distributes the heat better than stainless.

Well chock that up to one thing I never knew. I have to admit I've dipped on the temp a few times and I'm still alive. I could see maybe getting back up to temp and then extending the canning time by the minutes lost... But starting over seems extreme.

 

[Mickey328]

That's what I do Tanks. Mine tends to vary a fair bit both up and down, so I keep an eye on it and as long as it averages out to the pressure required I call it good. If it takes too long at sub pressure, I turn it up and leave it an extra few minutes.