How Are Canning Times Determined? (Answered)

How Are Canning Times Determined
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How Are Canning Times Determined

There is nothing quite like unscrewing a can just to taste that jar of pickles that you canned last July or the joy you derive from using summer’s juicy tomatoes in the middle of December. Sadly, not a lot of people can these days, despite the many benefits that canning offers.

Though it may be a simple process that you associate with your grandma, canning has changed tremendously over the years. This has paved way for a resurgence of this old but simple process that destroys food spoiling microorganisms and keeps food sealed in jars so that it keeps well beyond its anticipated storage period.

How Are Canning Times Determined?

How it all works

The most vital aspect of food canning is known as heat processing. Heat is applied to food that has been packed into a sealed or airtight jar. The process of heating can be done in either a boiling water bath or pressure canner.

The amount of time needed to process different types of food will vary based on the food’s acidity, its ability to transfer heat, as well as its density. For instance, canning green beans will require more time than tomatoes. The type of jar or container that is used as well as its size also impact the amount of time needed to can foods.

The processing conditions of the foods also vary but there is a minimum time required to make sure that all canned foods are sterile in a manner that does not destroy their flavor or nutrition levels. The sequence of steps utilized in the canning process also differs with every product being canned.

For example, fruits and veggies are typically peeled or pitted and stems are removed before the canning process can be completed. Seafood, on the other hand, has to be deboned and shelled with the exception of really small fish such as anchovies and sardines. Larger types of meats are sometimes cooked for a short time so that the outer flesh can be a little softened by heating.

If all these procedures are not followed to the letter during home canning the canning process will fail in result in spoiled food. Eating spoiled canned food can make you incredibly ill with the severity of the sickness ranging from mild to death.

Because it can be quite hard to determine the right canning processes at home, home canners must rely on established techniques and modern recipes that have been tested and tried.

How has canning changed over time?

As mentioned earlier, canning has changed tremendously since your grandma’s canning days. As such, if you are still using your grandmother’s or family’s old canning recipes, you should set them aside as they may have become outdated and unsafe. Today’s home canning recipes and techniques have improved and evolved considerably.

As a home canner, it would benefit you greatly to understand the current food canning recommendations and rules so that you can your food products safely. So how has food canning changed over the years?

Your old family recipes may be unsafe

Sadly, many old food canning recipes that have been passed on from generation to generation may no longer be safe to follow today. The standards of food safety and sanitation have changed, and so have the foods that are canned commonly. For instance, tomatoes today are a lot lower in acid content than the tomatoes that your grandmother used back in her day. Before tomatoes can be canned, acidifiers such as lemon juice, citric acid, and vinegar must also be added to all canned tomatoes to guarantee their safety.

This is basic information that we have at our fingertips today that was unavailable back then, which means that your grandma’s recipe might not have made the necessary adjustments, which could put you and anyone that consumes your canned foods at risk.

Instead of relying solely on grandma’s old recipe, consider finding another modern recipe that is close to your family’s old one and make the necessary adjustments. Before you use any old recipe, do your research to make sure that the acidity, ingredients, and processing times have been updated to the correct standards.

Some old canning techniques are now unsafe

Not only should you be wary of old canning recipes but also of any old canning techniques suggested. Traditional techniques that were once considered safe such as upside-down sealing or open kettle canning might seal your canned foods but the contents will not remain safe when they are stored.

For caning to be done properly, heat processing must be done over a specified amount of time in either a pressure canner or a boiling water bath to prevent the growth of bacteria. The acid content of the foods being canned is also relevant information that you must pay attention to in order to maintain safety.

In high acid foods such as tomatoes, pickles, and fruits, the botulism spores responsible for food poisoning can be destroyed sufficiently when boiled. That is why high acid foods are processed using a boiling water bath at 212°F. Other spoilage mechanisms such as mold and yeast are also killed after a boiling water bath.

Low acid foods, on the other hand, such as seafood, meats, veggies, and poultry should be pressure canned at 240°F to kill the botulinum spores, which are usually resistant to heat in low acid foods. As such, applying high temperatures, through a pressure canner, is the only practical way to kill these debilitating organisms.

If you were to attempt processing low acid foods in a boiling water bath, the length of time required to kill these organisms would range anywhere from 8 to 14 hours. Processing the same foods in a pressure canner would only take you between 45 minutes to 2 hours depending on the size of the jars that you are using, the manner in which you have packed the foods to be canned, and the type of food itself.

Other factors that might affect the way food is canned include:

  • Whether the food to be canned has been raw packed or hot packed
  • The amount of liquid contained in the jars; A higher content of fluid will allow the contents to heat faster.
  • The size of the chunks of foods being processed; larger chunks will take longer to heat than smaller ones.
  • The altitude in your city or region; you must adjust the processing time for altitudes that are above sea level.
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