Tuesday, July 10, 2012

Canning 101 - Methods of Canning

I find that canning is like planning a vacation.   First you need to decide on the destination or food to be preserved.  Are you looking for a simple place to stay, quiet,  kick back and read a good book;  standard peas and carrots, or something more exotic or adventuress like zip lining, rock climbing; salsa or spicy chili? 

Both are vacation, but they take you to different destinations, and will require different types of clothing and planning; Acid – Water Bath Method, or Low Acid – Pressure Canning. 

Generally all fruits are acid foods.   If you add vinegar to a recipe, like pickles and relishes, they are treated as acid foods.  The vinegar takes the place of the natural acid found in fruits, so their processing falls under the acid-water bath method.  (Note: When it comes to tomatoes, if processed by themselves are considered acid, but when added with other vegies like onions or peppers, they are treated as low acid.) 

The acidity that exists in acid foods can easily be destroyed, killing the mold and yeasts, by heating the filled canned jars in boiling water for a period of time.  Acid in food protects against the growth of bacteria.  

Water baths, are just that; a large pot of water, creating a nice jacuzzi for your canned fruits.  You can use a standard pot with lid, but it needs to be large enough for your filled jars to sit in, and allow for an additional 1 -2 “of water on top.  You’ll also need something on the bottom to keep the jars off the bottom of the pot, and enough room so the jars do not tip over or bump against each other.  The boiling water needs to touch all the surfaces of the jar for proper processing.

Low Acid
These are foods that contain very little natural acid, typically all vegetables, meats, poultry and seafood, soups, salsa (mix of tomatoes and other low acids like onions and peppers) are all treated as low acid-pressure canning method.

Low acid foods contain harmful elements of certain bacteria, not easily destroyed at temperatures up to 212 degrees F, so they need to be superheated to 240 degrees F.  In order to get to this temperature, we need pressure.  Without this, your food will spoil or you run the risk of getting sick.
Pressure canners, are a very specific type of kettle, with a lid that can be clamped or locked down to make a steam tight seal.  They typically have a safety valve (be careful what you buy at a yard sale, look for the newer ones for safety reasons) and a pressure gauge.  Please follow the manufacturer’s safety instructions, each model operates differently.  Also, there is a difference between pressure canners and pressure cookers.  You’ll need to allow for additional processing time, should you be using a pressure cooker versus a pressure canner. I’ll be using a pressure canner.  I’ve never used a pressure canner before, so we’ll be learning together.  In the meantime, please review the information in the link below.  It gives a lot of good information relating to the safety and use of pressure canners.

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