Pressure canning and losing liquid.

by Reggie

I am canning green beans and chard in an American Pressure canner. I am using Ball screw on rings with new covers every time. I leave one inch head space. I tighten the cover down with modest torque on the ring.

Liquid escapes from the jar into the canner every time. Is this normal? As an engineer (retired) I don't see how the pressure inside the jar can be greater than the pressure in the canner. Is this a head space issue?

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Hi Reggie, It sounds as if you are doing things right.

I've had others question why they loose liquid too. What happens is that as the food is boiling under pressure the contents of the jar expand. Then as it cools the lids are sucked down and a vacuum is formed.

It is common for some liquid to seep out into the water. You don't want too much liquid to boil out however.

When you open the lid to the canner the air will cool very quickly... much quicker than the jars will. This is when more siphoning may happen.

If you are loosing too much liquid you might be taking your jars out of the canner too soon. Be sure and let the canner cool down naturally. Don't try to speed it up by running cool water over it or anything.

When the canner pressure is back at zero. Take off the lid but let the jars set for about 5 minutes. Then take them out of the pressure canner.

I will sometimes just open the lid but leave it set on the canner cocked off to the side. (be careful of the steam it will burn your face or fingers!)

This will allow the jars to cool slower and the contents will not push out of the jars as much.

And this is coming from a very un-engineering type person! :0) So I hope it makes sense the way I explained it.

Sharon
SimplyCanning.com