For acidic foods like any tomato products, fruit jams or chutneys or pickles which have a vinegar brine, canning in boiling water is a safe practice. For anything without enough acid content like soups, chicken or beef stock or vegetables like beans or beats, you can't can them safely unless you have a Pressure cooker
. Do a bit of research if you want to can a recipe you are not sure about just to make sure. Canning is fun and easy, but be safe! Keep water boiling from the sterilizing step, and place jars down into the rolling boiling water.
If you have a boiling canning rack for your pot, you can load as many jars that fit on the rack and then lower them all on the rack into the water at the same time. As I said, I don't have a rack. When using a dish towel to keep the jars from touching the bottom of the pot, the towel won't be sitting on the bottom of the pot, but will be rolling all over in the boiling water. I lower the jars one at a time into the pot and make sure to push the towel down with the jar so it doesn't have contact with the hot sides of the metal pot. You want the water to be about 2 inches above the top of the jars. When you put the jars into the water, the rolling boil will stop for a while as the water has absorbed some of the coolness from the jars.Watch the water, and when it begins to be a rolling boil again, start timing for the sealing process. For salsa, I leave the jars in for 5 minutes.** After 5 minutes, take the jars out and allow to sit on the counter. As the jars cool, a vacuum will form in the jars and suck the lid down.
As the jars sit, you will hear an occasion ping. That ping indicates the seal has been successfully made. Its one of the most rewarding sounds in the kitchen!You may notice after a couple of hours that some jars haven't sealed
; the lid is not sunken down but still able to be pushed up and down. One reason your jars may not have sealed is because they needed more time in the boiling water. You can just reprocess them by placing them back in boiling water.
Try leaving them in for between 5-10 minutes.** They should seal up. If you have tried reprocessing a couple of times and the seals are not being made, there is always a chance you have a faulty jar or lid.*****Processing times are given for low elevation areas. For elevations of 3000-5000 ft, add 5-10 minutes to boiling time. For elevations above 5000 ft add at least 15 minutes to your process time.**Never use jars which have cracks or chips in the upper rim, and never use lids and rings which are dented or bent in such a way as to not allow full contact with seal to jar. If the lid does not have full contact with the jar, the lid may not fully seal, or worse, the jar may appear sealed but any crack in jar or nick in seal lid may allow a small amount of air through over time, which will create an environment for bacteria. If you ever pull a jar out of your pantry in which the lid is not sucked down but has popped back up in the center on its own, discard contents of jar and DO NOT eat.