Starting today, I'm going to write one canning tip per week. It IS the beginning of canning season, right? The strawberries are just about ready to burst, herbs are appearing, and canners are pulling equipment from their basements and shining them up for the season!
Pressure canners. Older pressure canners have a weighted gauge on their lids to help us humans determine inside pressure by listening to the jiggle of the gauge as it was rocked by the steam emitted by the canner. But newer brands rarely use this method of gauging pressure.
New canners succumb to our society's need for visual reassurance of correct pressure. They come with a dial gauge that looks similar to a clock face, only with the numbers 5,10, 15, and sometimes 20 printed on them. The numbers signify pounds of pressure.
At the beginning of each canning season have your dial gauge calibrated by your local extension office. I've never seen them charge for this service. You are usually asked to bring in your lid, with the gauge attached. Why is this chore important? Pressure causes your gauge to decalibrate a little at a time. You think you're applying 10 lbs. pressure, but in reality it is only 7.5 lbs. because the dial hasn't been reset. Dangerous if you are canning low-acid foods like beans or corn!