Pressure Canner

I have a presto canner.  The instructions say add 3 pts water to the canner, add jars, put on lid and vent for 10 minutes.  Then put on the rocking thingie.  Pressure can at 11psi for 75 or 90 minutes depending on jar size.  I have trouble keeping the psi at 11.  It goes to 15psi.  I have read that this is okay, but mu concerns running our of water in the canner at this high psi.  I made Ham and Bean soup yesterday using quarts and when cooled down, I opened the canner and there was hardly any water left from the 3 pts.  Does the high psi cause the water to be used up faster?  Should I add more water?  Any help would be appreciated.

Jerri, welcome to the forum!

I would suggest that if you are having trouble keeping the canner at 11psi then your fire is too high.

Next time lower your fire slowly while keeping it at 11psi.

The way the physics works is that the temperature of the water will go up steadily at a given amount of energy input until the boiling point is reached. At that point, the temperature will stay the same, just all the energy will go into converting the liquid water into gas. If the jiggler is jiggling non-stop, water is escaping as steam. If you can keep it at the point that the jiggler just barely jiggles every so often, you won't lose as much water. The amount of pressure is determined by the jiggler's weight and surface area the steam pushes against it. The higher the pressure, the higher the temperature inside. At 11psi the boiling point is 245 degrees; at 15psi it will be 257 degrees.

Thanks.  I got the canner up to 15psi and turned the electric stove down to low.  The pressure regulator barely rocked, but at the end of processing there was plenty of water still in the canner.  My heat was up too high as suggested by Anne and Jordan. I thank you both! Blessings