Sustainable Living Center Oregon
When we first got into canning, particularly pressure canning, we were nervous. Not so nervous that we would let our fear from doing it, but a healthy dose of caution guided our every step. We were like most people who are new to pressure canning could see images of explosions.
We thought that water bath canning as the ‘gateway’ to pressure canning. Water bath canning is used on high acid foods (pickles, jams, and jellies, etc.), and we use pressure canning for MEATS.
We even can the Crab and Salmon we catch, the chickens we raised and the deer we hunt.
We can meat instead of freezing it because it has a longer shelf life and more important if you lose electric power, you WILL NOT LOSE YOUR MEAT. The picture above of a sample of the meats, Dean has canned in the last two months. Most of the meat was harvested from sustainable resources. Now, he plans to supplement the meat with a supply of vegetables and fruit.
In water bath canning, as opposed to pressure canning, the jars are covered in boiling water and processed for a certain amount of time.
Water can only reach 100 degrees Celsius (212 Fahrenheit); the boiling water raises the temperature of the ingredients within the jar to kill bacteria. You use this technique for high-acid foods as they are safe to process at these temperatures.
Pressure canning uses less water (the jars aren’t covered) as it traps steam inside a pressurized container to raise temperatures beyond 240 degrees Fahrenheit. This allows us to preserve food that otherwise would require acid to be added to it.
A pressure canner is a heavy-duty piece of equipment with a vent, a pressure gauge, and screw clamps. It is capable of heating the food in the jars to hotter than the temperature of boiling water.
All low acid a.k.a. alkaline foods must be processed in a pressure canner, not a boiling water bath. What does that mean? It means that any unpickled vegetable, including vegetable soup stocks and all animal products, cannot be safely processed in a boiling water bath. You need a pressure canner for them and they are processed for a longer period of time while being under specific pressure for your altitude.
The reason for that is that although botulism bacteria is killed at the temperature of boiling water, botulism spores can survive that temperature. The spores can be eliminated by temperatures hotter than boiling water, which requires a pressure canner, or by creating an extreme pH (as is the case with vinegary pickled foods and sweet preserves).
Acidic and Non-Acidic Foods
Vegetables in plain or lightly salted water and animal products have a fairly neutral or slightly alkaline pH. Because the pressure canner creates temperatures hotter than boiling water, it can be used to process these non-acidic foods.
All acidic foods – fruits, pickled vegetables, sugar preserves, and tomatoes with a little-added acidity (lemon juice, vinegar, or citric acid) – may be safely processed in a boiling water bath. In boiling water bath canning, it is the acidity of the ingredients as much as the heat of the processing that safely preserves the food.
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