Pressure Cookers

What is a pressure cooker?
Modern pressure canners are lightweight, thin-walled aluminum or stainless steel kettles. Most have twist-on lids fitted with gaskets. There are still one or two that have screw-down knobs around the lid on the canner.

They have removable racks, a weighted vent port (steam vent), and a safety vent. They also have either a dial gauge for indicating the pressure or a weighted gauge (which both regulates the pressure and indicates, by rattling). Pressure canners can usually handle either one layer of quart or smaller size jars, or deep enough for two layers of pint or smaller size jars.

Unlike a water bath canner, the jars do not need to be completely covered with water. The directions that came with the pressure canner tell you how many cups of water to add in order for it to generate the right amount of pressure. You vent the pressure canner a considerable length of time while the water boils (with the jars in and the lid on). This causes steam to push out all the air. So the jars are in a space filled with only boiling water and steam. In theory, both will have the same temperature, which will be 240 F, substantially high than 212 F of an open water bath canner, due to the increased pressure. And since there is no air, just water vapor, the heat will be easily conducted to all sides of the jars.

Pressure Cooker Instructions for Canning

 * 1) Put the canner on the stove on the largest burner.
 * 2) Put the rack (usually a metal plate with holes in) into the canner and 2 to 3 inches of hot water into the canner.
 * 3) Place the filled jars (with the lids and rings on) fitted with lids, on the jar rack in the canner.
 * 4) Put the canner lid and seal it down. Leave the weight off the vent port (or petcock).
 * 5) Turn the burner up to its highest position. Heat until the water boils and steam exits strongly from the open vent port (or petcock). While maintaining the high heat setting, let the steam flow (exhaust) continuously for 10 minutes.
 * 6) Allow the canner to vent for the specified time (usually 10 to 15 minutes), then put the weight or on (or or close the petcock). The canner will get up to pressure in just a few minutes.
 * 7) Once the pressure gauge indicates that it has reached the desired pressure (often 11 lbs) start timing!
 * 8) Adjust the burner to maintain a the desired pressure, as shown on the gauge. If there is now gauge, the weight should jiggle a couple of times per minute, of course, check the manufacturer’s directions.
 * 9) At the end of the processing time (often in the range of 5 to 15 minutes; it varies for different foods altitudes and jar sizes), turn the heat off and allow the canner to cool down until the pressure is vented!
 * 10) Lift off the weight open the top and remove the jars! Carefully place the jars onto a towel or cake cooling rack, leaving about an inch of space between the jars. Avoid placing the jars in cold or drafty areas. Let the jars cool overnight (or about 8 hrs).

Source: Pick Your Own