Glass jar is used in home canning to preserve food. The mouth of the jar is threaded on its periphery to accept a metal lid. When tightened, the band presses a separately stamped metal tin- plated metal lid onto the rim of the jar. An integral rubber ring on the underside of the lid creates an airtight seal. Although these lids are reusable, the lids are disposable when canning. Having largely replaced other commercial canning products and methods, such as tin cans and plastic containers, glass jars and metal lids are still commonly used in home canning.
In home canning, food is packed into glass jars, leaving some empty “head space” between the level of the food and the top of the jar. A lid is placed on top of the jar with an integral rubber seal over the rim. The jar is heat sterilized by placing it in boiling water or steam and the lid is secured. The jar is then cooled to room temperature.
The cooling of the contents creates a vacuum in the headspace, pulling the lid into close contact with the jar rim to form an airtight seal. If the jar seal is formed correctly, the internal vacuum will hold the lid tightly to the jar. Most metal lids in use today are slightly domed as a seal status indicator. The metal lid of a properly sealed glass jar is pressed down by atmospheric pressure to form a concave dome. An improper or failed seal or microbial growth will cause the dome to pop upward.
Recommended size as below
:
4oz / 120ml for jam, spread, small servings
8oz / 240ml Suitable for jam, candied snacks
12oz / 360ml Suitable for jam and coffee cups
16oz / 480ml Suitable for jams, sauces, appetizers, pickles, oatmeal jars
24oz / 720ml Suitable for oatmeal jars , beverages, marinades, soups
Plz contact valiant glass if you want glass jars with lids，all of size in stock.
