# pressure guage on pressure canner



## yorkiebeebs (Sep 22, 2010)

I have a new pressure canner and wondered if I need to have the pressure guage checked. I thought I didn't need to have it checked until next year.


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## Macybaby (Jun 16, 2006)

When I bought my Presto a few years ago, the instructions actually stated to do a "test" run with the regulator in place (there was no weight). The regulator is actually a 15 lb weight. Said to take it up until the regulator started to rock, and that should be 15 lbs.

I bought the weight set so I go by that now, but the guage on my Presto seems right on. The one on my AA is not (same age) after only two seasons of use, this year it shows slightly higher pressure then indicated with the weight, but it no longer returns to zero either, and I know it use to.

I love having canners with guages, but I love using the weights to determine pressure.

Cathy


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## judylou (Jun 19, 2009)

In theory yes, you should have it tested. Gauges right out of the box have tested off by 4-5 lbs. Better yet, buy the weight set for it and then you can ignore the guage completely. Guages are meant to be general guides only.

Meanwhile as Macy suggested do the 15 lb counterweight test to get a ballpark figure on the gauge.


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## yorkiebeebs (Sep 22, 2010)

My pressure canner is the All American and it has a weight and the guage. With the weight on 10lbs it was consistently 11lbs on the guage. I've already done canning with it and never even considered there would be a problem. Everything looked good when I was watching it. I suppose before I eat anything, I should take them down and have them checked. I wish I had known this. I'm nervous enough eating pressure canned food as it is.


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## Ozarkquilter46 (Jun 5, 2002)

how and where do you get the gauge tested


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## judylou (Jun 19, 2009)

> My pressure canner is the All American and it has a weight and the guage.


Then you don't need to worry about the gauge. You just ignore it. The weight is by far the most accurate anyway.



> how and where do you get the gauge tested


Local county extension offices IF they are still doing the testing, many aren't doing it any longer. Otherwise you have to send it back to the manufacturer. That is why the current recommendation to convert all gauge canners to weighted-gauge canners.


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## yorkiebeebs (Sep 22, 2010)

I just returned from having the guage checked and it's perfect. What a relief! Thanks everyone, I didn't even think about having it checked.


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## Pouncer (Oct 28, 2006)

JudyLou, I am confused....I too, have an AA, with gauge and weights. These weights do not really rock, imo. I have one canner whose gauge is off based upon sounds from the weights alone-maybe two pounds. It hisses and spits as the gauge creeps past the targeted pounds. 

I have one that seems stable at 11 pounds, and the other at 12 1/2, on both I have the ten pound weights on. One canner is spitting and hissing like crazy, the other is quieter. I just figure that processing at a couple extra pounds is okay? And no, I never, EVER cut down processing times, for any reason.


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## Just Cliff (Nov 27, 2008)

yorkiebeebs said:


> I have a new pressure canner and wondered if I need to have the pressure guage checked. I thought I didn't need to have it checked until next year.


Not on a new canner. If you take care of your gauge it will be good for many years to come. Guages are very accurate. Far more accurate than a little jiggly weight. Due to manufacturing differences. Weights can be off a great deal. They are not checked at the factory like a guage is. All it takes is one tiny burr that you cant see and your pressure is up or down a great deal. Weights are the equivilant of the idiot lights in your car. Guages on the other hand give you the true story of what is going on with your canner. Not only will it tell you an accurate pressure. You can watch the needle for signs that something is not right. (faulty seal, weight or something else). Experience is your best friend. Take the time to really see how this piece of equipment is operating. Then,in the future you will be able to tell if everything is operating the way it should be instead of just listening to it.


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## judylou (Jun 19, 2009)

> Guages are very accurate. Far more accurate than a little jiggly weight. Due to manufacturing differences. Weights can be off a great deal. They are not checked at the factory like a guage is. All it takes is one tiny burr that you cant see and your pressure is up or down a great deal. Weights are the equivilant of the idiot lights in your car. Guages on the other hand give you the true story of what is going on with your canner. Not only will it tell you an accurate pressure.


I'm sorry but with all respect to Cliff, that just isn't accurate information and could be quite misleading to many. There is ample scientific testing of both gauges and the machined and tested weights to prove that the weights are far, far more accurate and that the guages, regardless of the manufacturer are very prone to false readings. Even the canner manufacturers themselves concede that point and it is the reason that many new models of canners are now being sold with ONLY weight and no gauge or with both gauge and weight. 



> AA, with gauge and weights. These weights do not really rock, imo.


You are quite correct. AA weights "spin" rather than rock or jiggle and they hiss and spit at the same time.  Same for some of the Mirro models. Presto's rock (no pun intended). Basically with the AA any type of movement of the weight is a valid indicator of the weights pressure as the 10# weight will spit and spin at 10.5 lbs. of pressure. Your gauge, if it is accurate, it will read 11 lbs. at that time. So your one gauge is ok but the other may be off a lb. or 2.

The goal with the AA is to get it to do that 3-5 times per minute although more frequently than that is fine too. A couple of extra lbs. of processing is no problem. It is the UNDER-processing that poses safety issues and if one relies only on a gauge and that gauge is not tested annually then the odds of under-processing are quite high.


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## Pouncer (Oct 28, 2006)

JudyLou, it would sure be nice if the literature accompanying those canners had said anything about that! As I recall the weights were described as performing a pressure release function, and to help maintain the pressure inside during processing.


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## Cyngbaeld (May 20, 2004)

Any radiator repair shop can test the gauge for you, no need to send it to the factory.


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## Pouncer (Oct 28, 2006)

Cyngbaeld, I did ask my hub about this (he has worked small engine in the past, so knows a lot about local mechanical shops) and he assured me that they don't do that. They would need to have a variety of canners to test lids, including one calibrated correctly as a standard. 

No such service here, unfortunately. Besides, have you ever actually been inside one of those places? Every radiator shop I have seen is a filthy mess, no way would I let a kitchen item spend any time there, lol


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## judylou (Jun 19, 2009)

> JudyLou, it would sure be nice if the literature accompanying those canners had said anything about that! As I recall the weights were described as performing a pressure release function, and to help maintain the pressure inside during processing.


I agree with you 100% Pouncer. Unfortunately canner manuals are rarely up-dated. Many of them still rely on information first written in the 60's or even earlier. That is one reason why using a canner manual for canning recipes is strongly discouraged. 

Compressed air gauges, when first invented, were considered progress in its prime. So much so that for decades canners were made with ONLY a gauge or with a gauge and only a petcock safety valve. But progress in canner manufacturing has come along way since then. Sadly the paper work hasn't kept up with the product.


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## Just Cliff (Nov 27, 2008)

judylou said:


> I'm sorry but with all respect to Cliff, that just isn't accurate information and could be quite misleading to many. There is ample scientific testing of both gauges and the machined and tested weights to prove that the weights are far, far more accurate and that the guages, regardless of the manufacturer are very prone to false readings. Even the canner manufacturers themselves concede that point and it is the reason that many new models of canners are now being sold with ONLY weight and no gauge or with both gauge and weight.
> 
> 
> 
> ...


No. You are incorrect. The two pieces serve two different functions. There has never been or will be any ample scientific testing reguarding the the two parts. 
The weight, is a regulator and incapable of measuring pressure
The guage measures pressure and is incapable of regulating pressure
Guages are prone to false reading when not cared for properly.
The only point conceded by manufactures is price. ALL high end pressure canners have a guage. 
Mirro,The low end, has none.
Industry standard (ASME) on low end guages is 2.5% A very low percentage.

I have built 7 testing units for Underwriters Laboratories, 3 air scrubbers for a nuclear power plant in NC and CA and 2 for the Centers for Disease Control in addition to many other low and high pressure steam products.
Im pretty confident that I know what I am talking about.


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## Macybaby (Jun 16, 2006)

Just Cliff, sounds like you are in the realm of "rocket science" while the rest of us are just trying to do some home canning.

Studies for home canning have shown that a home canner is better off using the weight sets to regulate the pressure than to use the gauge and adjust heat to maintain proper pressure. Mostly because the heat source we have available isn't usually as adjustable as it would need to be.

Sounds like you get to mess with some pretty high end technical, and probably expensive equipment. I paid about $70 for my Presto canner, I wouldn't call that a very sophisticated piece of machinery. 

Since this is the "preserving the harvest" forum, discussing pressure systems at nuclear plants is a bit above most of us.


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## judylou (Jun 19, 2009)

Gee Cliff, when building those highly technical pieces of equipment I sure hope you were using higher quality gauges than the classy $12.95 cent ones that come on all the pressure canners? The ones where if you tap them with your finger they will often jump 2 lbs. or read off by 4-5 lbs. right out of the box. 

Be that as it may, "machined to spec tolerances" weights are exceptionally accurate and both FDA and USDA testing labs documentation strongly support that fact and advocate the use of those weights rather than the gauges on home pressure canners. 

Weights may allow slight over-processing of the foods but they cannot allow any under-processing as the gauges easily can. And it is that potential for UNDER-processing by using a faulty gauge that poses the food safety risks.


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