# Why would a pressure canner warp



## PrettyPaisley (May 18, 2007)

What would cause this? The old Presto I had (yes, a Walmart special), warped after only a couple of years of very light use. The bottom of it bowed out so it does not sit flat on the stove. 

I have a gas stove and at the time it was hooked up to natural gas. If I get another cheap Presto to hold me over until I have extra cash for an All American, what are the chances it would warp again?


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## suitcase_sally (Mar 20, 2006)

Slim to none. I have 5 large canners of just about any imaginable brand and have never had one warp.

The only things that I can think of that might make one warp are

1.) Heating it while empty on a very hot stove.

2.) Too much pressure - the overpressure plug not popping when it should have.

3.) Having it run dry while canning

BTW, All Presto's are made to the same standard. Having bought it at WalMart has no bearing.


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## 1shotwade (Jul 9, 2013)

Sally,that's not necessarily true. I have had many people tell me how big box stores like walmart and lowes contract with manufacturers to produce items with their specs. instead of the manif. specs. and do it at such volume that they will actually "sell" their name on the product.I have had many walmart products that did not hold up.I just talked with a john deere employee a few months ago that told me the "LA" model of john deere that is sold by the big box stores is actually produced by MTD , but they preorder such a large volume that john deere can't turn it down. What you are buying is a MTD with a John deere paint job.I feel this to be true and it seems to be true with many items.


Wade


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## Marilyn (Aug 2, 2006)

I've heard the same thing Wade, about name brand name faucets sold at Menards.

*Pretty Paisley: *If you eventually want an AllAmerican, why spend half the cost on something else first? Just bank it and add any dribs and drabs of extra cash to the fund. You'll have the purchase price before you know it. The redundancy of a pressure gauge as well as a pressure regulator is very comforting.


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## where I want to (Oct 28, 2008)

I know from personal bad behavior that it is possible to warp a pot exactly in that way by running cold water into itor putting it into cold water while it is still very hot. I have not done it with a pressure cooker but I suppose there is no reason why not there too.


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## suitcase_sally (Mar 20, 2006)

Part of the process of using a pressure _cooker_ is to run cold water over it, and though this is a canner, I wouldn't think that would hurt it.

Paisley, if you are using a gas stove, it shouldn't affect the canner because the flame follows the shape of the pot. I'd go ahead and use it, unless it's warped so badly that the jars don't sit even - but the rack should alleviate that.

1shotwade, I did not know that. It would sem to me that John Deere (and others) would not want to ruin their reputation like that.


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## PrettyPaisley (May 18, 2007)

From the list that sally gave I assume what happened is that is went dry. I'm no pro at this and I do recall opening it once and there was no water left in it after it was opened. 

I would never run water over it to cool it off. I'm terrified to touch it once the canning process starts and I will sit up all night long to wait for the pressure to release so I can safely take the lid off. I won't even turn the stove off and go to bed and wait until morning. I got instructions on how to use the pressure canner off this site and I follow them to a "t". 

I do can on a gas stove so I think I will go ahead and use the warped one. I guess I should say it's more "bowed" than warped; the bottom pokes out a bit instead of being flat. It does not affect the way it seals or cooks as far as I can tell. I've used it since not knowing that I should worry about the bottom being out of whack.


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## simi-steading (Sep 27, 2012)

I'm thinking the bottom is too thin...


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## Breezy (Jun 5, 2009)

I've warped a canner bottom, it ran dry. I'm not sure why it went dry, maybe it had needed a new gasket? This was quite a while ago. 

It was a Mirro. Per the company, they suggested hammering it out. We laid a piece of wood over the bottom, and hammered that...it worked! It had the rocker style of gauge, so I felt it was getting up to and holding pressure afterward.

I did replace it with a Presto canner soon after that, as I had been wanting one. My Presto has the dial gauge, which I like.


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