Glass canning jars are available in a range of sizes and styles designed specifically for home canning. Different types of canning jars are available, with their appropriate use determined by the method being used and foods being preserved. All glass canning jars are suitable for use in pressure cookers and boiling water canners, and they generally are reusable. Some jars also are labeled as suitable for both canning and freezing. Glass jars used for commercially manufactured products should not be used in home canning, because such jars are intended for one-time use.
Glass canning jars are available in either wide-mouth or regular-mouth designs. Wide-mouth canning jars are used for canning larger produce and for ensuring easier access to the contents after canning. The wide-mouth jars are straighter and more uniform in shape, whereas regular-mouth jars taper inward at the top. Regular-mouth jars are better suited for sliced produce, syrups and jams. Canning jars are most commonly categorized by their size and intended use, and not all types are available in both wide- and regular-mouth varieties.
Wide-mouth jars in the United States commonly are sold in three sizes suitable for home canning — pint (16 ounces/473 milliliters), quart (32 ounces/946 milliliters) and half gallon (64 ounces/1.9 liters); glass canning jars sold in Europe and elsewhere use metric measurements and are similar in size to the U.S. pint, quart and half-gallon jars without being directly equivalent. Wide-mouth pint jars are commonly used for preserving salsa, fruit butters, relishes and foods that will remain in the jar until fully consumed. Wide-mouth quart jars are designed for canning whole or halved fruits and vegetables. The wider opening allows larger foods to fit easily and provides better access. Half-gallon jars are less common and are designed for preserving grape or apple juice; they typically are not recommended for use with other foods.
Regular-mouth glass canning jars are more versatile and come in a wider variety of sizes in the U.S. and elsewhere. Jelly jars come in 4-ounce, 8-ounce and 12-ounce sizes in the U.S. and are used for canning jelly, jam, marmalade, preserves, condiments and similar foods. The smaller jars are suitable for storing smaller quantities to avoid waste. Most jelly jars are decorated with outer ridges or designs and may be attractively packaged by home canners for gift giving. Half-pint (8-ounce) jars also may be used for preserving fruit jellies, sauces and syrups.
Regular-mouth pint jars are commonly used the same as wide-mouth pint jars. They also are used for canning pie fillings and smaller quantities of sliced fruit to store smaller portions. Quart-size jars are designed for sliced or chopped vegetables and fruit, fruit sauces, soups and similar foods. Only those marked “freezer safe” are suitable for both canning and freezing. Freezer-safe sizes and types include regular-mouth jelly and half-pint jars, as well as wide-mouth pint jars.