Can foods to preserve them by using either a hot water method or a steam method. The hot water bath method is safe to use for high-acid foods such as tomatoes and fruits. All other vegetables should be canned using the steam method to ensure complete bacteria eradication. Canning using the hot water method is a basic process, but you must follow strict sanitation guidelines to prevent food contamination.
Fill a sink half full of hot water and 2 to 3 tsp. of dish soap. Insert each of the canning jars and lids into the water, and wash them thoroughly with a sponge. Rinse all the items in hot water to remove the soap residue and then allow them to air-dry.
Fill each of the glass canning jars with the desired food until it reaches 1 inch from the top of the jars. Add 1 tbsp. of lemon juice or 1/2 tsp. of citric acid to each jar.
Insert a rubber ring, or metal circle, into the inside top of each lid, and screw the lids tightly onto each jar. Insert each filled jar into the canning rack, which looks like a wire basket.
Fill the metal canning pot with tap water until it is half full. Place the pot on a stove burner turned to "High." Allow the water to heat up until it reaches approximately 140 degrees Fahrenheit. Check the temperature periodically with a food thermometer.
Insert the canning rack into the hot water, making sure that there is at least 1 inch of water above the top of the jars. Add more water if necessary to reach this level.
Place the lid on top of the canner and wait until the water boils rapidly. Next, lower the heat to "Medium" or "Medium High," depending on your stove, so that you maintain a gentle boil.
Wait the proper amount of time, depending on the food you are canning, and then turn off the stove burner. Remove the lid, using a pot holder, and lift the canning rack out of the water.
Remove the jars from the rack and set them on a cutting board with at least 1 inch of space in between them. Let them remain there until they cool.