Pressure canning is important for you who preserves low-acid foods from the garden. For safety, vegetables, meats, soups and other low-acid foods you process in pressure canner. They must reach 240 degrees F during a set time to kill harmful bacteria especially Clostridium botulinum.
During pressure canning, part of the water turns to steam; when all air exits through the vent pipe you lay the pressure regulator on it
Pressure Canning Safety and Timing
Water boils at 212 degrees F at sea level, but at lower temperature when height grows. Hence the times or heats for killing germs adjust with the height. In 8001 until 10 000 feet, you add 20 minutes to the process time.
Recipes for canning count that, so you adapt to differnet levels.
The process duration depends much on the preserved foods. Green beans require 20 minutes for pints and 25 for quarts. Beef or venison require 75 minutes for pints and 90 for quarts in 10 PSI sea level.
Birds likewise: 75 for pints, 90 for quarts. For high-acid foods as fruits and jams, suffice around 10 minutes, and pressure cooker do not help a lot hear.
In half-gallon bowls with vegetables or meat, you extend the time by 20 percent compared to quarts. Reliable recipes point precise times and pressures for every case. They are tested individually, so there is not one table for everything.
Before start the timing, the canner discharges steam during full 10 minutes. Later the weight covers the vent hole, and the pressure grows during 3 until 5 minutes. Additional 15 minutes or so last until full pressure.
The canner pressure sets the water heat around the bowls, and timing does not start before it reaches that.
When the timer end, turn off the heat and leave the pressure slowly fall to zero. Then remove carefully the pressure weight, start new timer for 10 minutes, and later open the lid. Do not rush!
Some protein foods require until 110 minutes of process, except the long warming and cooling. The whole process, with preparation and cleanup, easily last five hours. It involves whole partofday, but value the effort.
Pressure canning is not difficult, only time-consuming.