World War II was a time in which home canning started to become popular. It offered families a way to supplement their food supplies when rationing was in effect during times of food shortages. This was further driven by cold winters in Canada and the inability to grow produce during the winter. Nowadays, preserving can be used as a way to reduce household food waste. A lot of produce is wasted in households because it is bought in bulk and mass quantities and goes bad before it is eaten. Preserving can be used as a means to prolong the life of these foods. In addition to reducing food waste, home canning can save you the cost of store bought canned goods and out of season produce that tends to be expensive.
Preserving includes different methods of fermenting and canning. Fermenting is an easier method of preservation because it is tolerant of imperfections such as variations in time, temperatures, and ingredient ratios. Fermented products are preserved by the actions of microorganisms. Microorganisms, such as bacteria and yeast, consume sugars and can have many products including acids and alcohols.
The second method of preserving, known as canning, is more complex. There are two common ways to can: water bath canning and pressure canning. The method that is used will depend on the acidity of the food. High acid foods should be preserved using water bath canning. These foods include most fruits and vegetables. Low acid foods should be preserved using pressure canning. This includes foods such as red meats, seafood, poultry, milk, and some vegetables.
Home canning has many benefits. When food is enjoyed within its natural season, it will have the best flavours and the peak nutrition. Canning extends the time that you can have certain fruits and vegetables at their peak flavour. The high percentage of water in most fresh foods makes them perishable if left on their own. They can spoil because of growth of undesirable microorganisms, reactions with oxygen/exposure to air, and moisture loss.
Canned food is preserved through the use of heat and acid; when done properly, home canning is safe. To maintain good natural colour and flavour in stored and canned food you need to remove oxygen from food tissues and jars, quickly destroy the food enzymes, and obtain an airtight seal to keep air and microorganisms out, while keeping moisture and freshness locked in.
1 United States Department of Agriculture National Agricultural Library — Canning Through The World Wars