Preserving food through a home canning process is a time-honored tradition especially popular before every household had refrigerators and frozen food was readily available. The popularity of home canning was started around 1860 when a New York tinsmith named John L. Mason invented a glass jar with a reusable metal lid and threaded lip, now referred to as the Mason jar.
Food preservation through canning has continued through the generations as there is a satisfaction in having the whole family involved in picking and preparing your own fruits and vegetables to enjoy later in the year. Special pressure cookers even allow canning of fish and meats.
Understanding the Science Of Canning
Nothing beats the taste of fresh local foods, and the best way to safely preserve those flavors is by home canning. The process is simple, involving the application of heat to food that is contained in a closed glass jar to interrupt the natural decay of the food. All foods and the air around them contain different microorganisms such as bacteria, yeasts, mold as well as enzymes. Canning allows control of these factors to prevent food from spoiling.
The canning approach depends on the acid levels of the food. Some foods like fruits and vegetables like tomatoes and pickles using added vinegar are high acid foods. Low acids foods include meats and other vegetables. High acid foods require heat processing to 212 F, and low acid foods need to be heat treated at 240 F to inhibit spoilage.
The simplest home canning approach is water bath canning. Jars filled with acidic foods such as berries, tomatoes, or cucumbers in vinegar are covered with lids, and boiled in an open pot of water until a seal is formed under the lid. The heat from boiling forces air out of the jar, creating a vacuum. The acidic environment and lack of oxygen prevents harmful bacteria from forming.
A more advanced canning technique is pressure canning, used for low acid foods. The pressure cooker is a specially designed pressure system that prevents steam from escaping, increasing the temperature in the canner to the necessary level. Pressure canning allows preservation of a wide range of foods.
Safe canning requires the right amount of heat for the right length of time, proper preparation of foods being canned, and precise salt/sugar and acidity levels. Grandmother’s treasured recipes and approaches may work well. However, to ensure safety and best preservation of foods, it is best to use canning recipes that have been tested by food scientists.
Basic Canning Equipment
It is easy to set up a home canning system. The basic equipment is inexpensive and readily available. Tools needed include:
- Jars and two-piece lids
- A large pot to prepare the food
- A deep pot with a lid and rack for high acid foods, or a pressure cooker for low acid foods
- Measuring spoons and cups
- Tongs, a jar lifter and funnel
- Steps in the Canning Process
The process for canning is not difficult. Start with collecting the best and freshest foods for preserving. Then follow these steps:
- Review the recipe to ensure all ingredients and tools are available
- Fill the canning pot with water and bring it to a boil; follow manufacturer’s instructions to prepare a pressure cooker
- Clean and sterilize jars in simmering water
- Place lids in hot water until needed
- Prepare the ingredients and fill the jars
- Wipe the rims and screw on the lids
- Boil the jars for the necessary time
- Remove and cool undisturbed for 24 hours
Involving children in the canning process will produce life-long memories for them. Preserving food using the canning method ensures high quality and flavorful meals, saving money and helping build up the family food stores. The family who invests time in home canning has food in reserve for winter treats and is prepared for emergency situations.