Putting Food By - Janet Greene [27]
Fourth, gauges, vents, and gaskets of pressure cookers may not be checked so carefully or so often, as the sensible householder will do with a Pressure Canner during the season. Less than perfect operation while cooking a Swiss steak is no big deal, but a hitch during Pressure-canning could mean food poisoning when the contents of the containers are eaten several months later.
Many a cook has cooled a pressure cooker quickly under running water in order to inspect the progress of loose food being cooked inside. Doing this with canning jars inside will make a grade-A mess.
Buying a Pressure Canner
Pressure Canners are usually made of cast aluminum. Like B–W Bath kettles, they come in sizes measured according to loose-contents capacity; unlike B–W Bath kettles, though, their diameters are all roughly the same: it’s their height that varies. The most popular sizes are 16-quart (actually taking 7 quart jars or 9 pint jars), and 22-quart (actually taking 7 quarts, or 18 pints in two layers, or 34½-pints stacked in three tiers).
They’re expensive, but they do their job for years and years if you take good care of them and keep their sealing rims and pressure gauges and safety vents in good working order.
The Anatomy of a Pressure Canner
The base, or kettle, is covered with a tight-fitting lid that contains the controls. The lid is fastened down with clamps or a system of interlocking ridges and grooves, bayonet style. It may or may not have a rubber gasket.
Controls are: (1) a pressure gauge—a dial, or a system of measured deadweight that sits on the vent; (2) an open vent to let air and steam exhaust before processing time begins, and is closed with a petcock or separate weight (if gauge is a dial) or with the deadweight gauge, to start raising pressure; and (3) a safety valve/plug that blows if pressure gets unsafe.
The canner also will have a shallow removable rack to keep jars/cans from touching the kettle bottom, or a strong wire basket that serves as a rack and lets you lift all the hot containers out in one fell swoop.
Pressure Canner for a B–W Bath
Put in enough water to come up to the shoulders of the jars you’ll process; start the water heating. Put in the filled jars, taking care lest they touch the sides or each other; of course they’re on a rack that holds them off the bottom of the pot. Then lay the heavy lid on the sealing rim of the canner, but do not lock it. Leave the vent open. (These terms come up in the complete description of the operation of the Pressure Canner soon; meanwhile this much of them belongs here because we’re talking about B–W Baths, not Pressure-processing.) After a strong flow of escaping steam is established, start timing as for the B–W Bath recommended for the strong-acid food you are treating.
If you lock the lid, you will get 1 to 1½ pounds of pressure, even with the vent open. At PFB’saltitude, this is good. We use it only to ensure that our B–W Bath is hot enough; it’s not any alternative to correct Pressure-processing.
Servicing Your Pressure Canner
First, read the operating manual that comes with it.
Next, clean the canner according to directions, to remove any factory dust or gunk. Do not immerse dial in water.
Check the openings of the vent, safety valve, and pressure gauge to make sure they’re unclogged and clean. Take a small sharp-pointed tool (like a large darning needle or a bodkin) to the openings if they need it; clean the vent by drawing a narrow strip of cloth through it.
Be sure the sealing surfaces of kettle and lid are smoothly clean, so they’ll lock completely tight and not allow any pressure, in the form of steam, to escape. If your canner has a rubber gasket, replace it when it shows signs of losing its gimp or getting hard or tired; it should be as limber as a good jar rubber. The kind of hardware store or online store that has replacement dial gauges is likely to have gaskets as well. If shopping at a brick and mortar store, take your canner lid with you to make sure of the right size (and don