Putting Food By - Janet Greene [38]
Set the rounded glass lid of your bailed jar on the rubber ring, turning the cap so the notch in the top will catch the wire most securely; push the longer hoop up over the top of the lid until it’s held firmly in the notch. (But don’t snap the lower bail down on the shoulder of the jar: you’ll do this after the jar is processed.)
Post-Processing Jobs
Your B–W Bath kettle is off the heat, your Pressure Canner has returned to Zero—but not until tomorrow will today’s canning be finished.
As you remove cans to drop them in cold water, mark the ones with poor seals. Right now, hot from the canner, their ends should bulge from internal pressure sealed in; and in the cooling tub, tiny bubbles must not appear around the lids. Therefore flat ends or bubbles mean pinpoint gaps in the sealing seam.
On the other hand, your jars seal themselves as they cool. Of course you never tighten the modern “dome”/“snap”/“self-sealing” two-piece screwband metal closures. But when you “complete seals if necessary” by flipping down bails that have separate rubber rings, you are not actually making the seal: you are merely securing the lids firmly in place so the ensuing vacuum can complete the seal.
For this reason, don’t open the jar to add liquid if you notice one whose liquid has partly boiled out during processing. Simply treat the jar normally and stand it up beside the others. After cooling undisturbed overnight, it might have a good, safe seal.
Two more things. Cans aren’t shockproof just because they’re already sealed and are made of metal, so don’t bump them around or transport them until they have cooled and rested overnight. And don’t invert or shake—or even tilt—jars before they’re cold and sealed.
Checking Seals
The day after canning is the time for checking the seals of your containers and preparing them for storage. And this is your ONLY chance to salvage food that has failed to seal; once it is stored, a bad seal means that you must destroy it.
CAN SEALS
By now the ends of your cans should be pulled slightly inward, proving that there is a vacuum inside. However, if the end of a can has not collapsed, press it hard: if it stays in, the seal is OK.
Be right finicky as you check your cans, because at this early stage a poor seal will not have had time to become dramatic. Therefore the ends won’t be bulging way out (certainly not even so much as they did right after the cans were processed yesterday); nor will the seams be leaking gassy, spoiled food (although traces of food at any seam are an obvious sign, since the cans got well rinsed by the water in which they cooled).
Springy ends and bits of food mean bad seals. Open the cans and refrigerate the contents, to serve or reprocess. Re-can and process anew only if failures in the batch warrant doing so.
JAR SEALS
First, don’t be dumped if there’s a haze of dried canning liquid on the outside of some jars. All your jars vented in the processing kettle, remember; and several may have lost liquid, which clouded the water in the canner and so left a slight deposit on the jars.
Food particles lodged around the base of the closure could mean trouble, though. You’ll know for sure when you check your seals.
On your modern mason jars, the metal lids of the two-piece screwband closure will have snapped down, pulled in by the vacuum that means a good seal. If you find a lid that is not concave, press it: if it springs back, the seal is gone; if it stays down, its chances are better—but set this jar to one side for a tougher test you’ll give questionable jars in a minute.
Test bailed jars by tilting them far enough so the food presses against the closure. If bubbles start at the lids and rise through the contents, the seal is no good. Moisture appearing at the sealing point is a bad sign too.
Now for the really tough second test. Take a jar you have doubts about—modern mason with its metal lid or any with a bailed closure