Canning Jars - What You Need to Know!
A Mason jar (" Mason's jar") is a specifically molded, sealed glass jar used in homemade canning to retain food for longer periods of time. The jar's mouth is lined with a thin, clear glass ring or "rod" to accept a thin metal band or "brace" to keep the lid tight. It is sometimes called a mason hard jar. Mason jars have historically been made in the United States and are still popular in this country today. They can be used for canning vegetables, fruits, meats, and dairy products.
Today's canning jars have a variety of different types of glass lining, as well as various sealing surfaces. The glass sealing surface can be one of several types of vitreous China, such as vitreous gum, gesso, or even polyester film. Some home canning jars have a double walled, lidded, or stainless steel sealing surface. The most common material for the sealing surface of modern canning jars is polyester. The use of other materials for sealing and lidding is not as common today as it was in years gone by.
Some canning jars have a plastic inner liner, called a "lossle", that seals the top of the jar. Other lids have an outer plastic liner, called a "perforated lid", that serves the same purpose. There are also some varieties of canning jars that are designed with a built-in, self-cleaning lid, that can remove a small amount of air from the jar prior to closing. These types of lids are available from some manufacturers, but not from the jarden corporation. Self-cleaning canning lids are quite convenient, because they do not require a second person to close or open the lid.
Many different varieties of canning jars are available today. One type that is very popular is the canning jar with an airtight seal. These jars have an inner airtight surface, and the neck of the jar does not include an airtight seal. These are a popular choice for many people who prefer freshness over durability. However, because these types of jars are so inexpensive, many people choose them for cost-cutting measures only. A more durable variety would be a glass jar with an airtight neck.
Another variety of canning jars is the one that includes a detailed list of what the expiration dates are for the jars. This information may be on a separate piece of material placed within or on the label of the jar. There are some people who simply do not want to know when their jar of preserved food is due to expire. For these people, canning recipes are simply not sufficient to provide the expiration information that they need.
The labels that come with the jars are placed inside of a rubber ring that is glued to the lid of the jar. The rubber ring then is inserted into the jar so that it holds the lid in place. A water-tight seal is created by using pressure to make a seal. After placing the jar lid into the canning pot, the canning process begins. In general, boiling is first used to reduce the pressure in the jar so that the boiling water can flow through the jar easily.
After the boiling water is added to the jar lids, the canning process moves quickly from boil to boil. The boiling water is allowed to evaporate into the atmosphere. This evaporation takes place at a very high temperature, which in turn kills any bacteria that may be present in the water. After the liquid has cooled, it can be transferred to the jars using the tongs that are provided with most canning jars. The jars are then placed in the boiling water bath for a brief period of time so that the water can permeate the inside of the jars and create a seal for the contents of the jar lids.
The canning process does not end there. After the jars have cooled, the canning instructions or label is read so that the correct amount of water is added so that the jars can be placed into the steamer and the lid placed on. At this point, the canning jar lids are removed, the steam comes to the top of the jar, the lid is removed, and the steam is released. The sealing process is complete, and canning jars are ready for use!