Why and what of canning

Yield: 1 servings

Measure Ingredient


WHY must I follow the recipe directions and processing times exactly? The recipes in canning books have been developed and tested by experts to allow for enough heat and time to destroy the microorganisms that would spoil food or cause illness. Never substitute ingredients, jar sizes, or methods in home canning recipes. Shortcuts are dangerous.

WHY do different recipes have different processing techniques, times, and temperatures? Foods vary in their physical characteristics. Some take longer to heat through, and others may be susceptible to certain types of bacteria or spoilage. The different times and temperatures are related to the type of food being canned.

WHY do I need to know about acid and low acid foods? Because the acidity of the food determines how bacteria can affect it, thus determining the processing method you must use.

WHY can't I use the boiling water bath method for both acid and low acid foods? The temperature food reaches in a boiling water bath isn't high enough to kill the spores of the botulism bacteria.

Illness is caused by the toxin produced when these particular bacterial spores are present in foods in the absence of air. This may occur in foods that are low acid or that have become low acid. All vegetables except tomatoes are low acid. Other low acid foods are meats, poultry, fish (seafoods), soups, and mixed canned foods. Acid foods such as fruits, tomatoes, sauerkraut, pickles and relishes, jams and preserves, and fruit juices may become low acid by using over ripe fruit, by adding excess water, or through the growth of mold. Sweet peppers are particularly low acid foods and require special precautions in processing. Follow the recipes exactly! WHY is the timing of the processing so important? The processing time must be long enough for the food in the center of the jar to reach the temperature necessary to destroy all the harmful microorganisms. Don't shorten the time or take shortcuts. Begin counting processing time only after the water in a boiling water bath canner has returned to a full rolling boil or after the pressure in a steam pressure canner has reached 10 pounds pressure. Use an accurate timer or watch.

Source: Vegetable Gardening Encyclopedia Typos by Dorothy Flatman 1995 Submitted By DOROTHY FLATMAN On 10-04-95

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