This section is from the book "Save It For Winter.", by Frederick Fry Rockwell. Also available from Amazon: Save It For Winter; Modern Methods Of Canning, Dehydrating, Preserving And Storing Vegetables And Fruit For Winter Use, With Comments On The Best ... For Saving, And When And How To Grow Them.
For keeping Vegetables or fruits by any of the above methods, of course, the two important things are the preparation or sterilization, and a container which will keep the food sterile after it is prepared. In modern methods, however, the container, in which the product is packed cold, is used before the sterilizing apparatus and, therefore, described first.
There are several distinct types of both glass jars and tin cans. For most of the home uses, jars are to be preferred to cans. while the original cost is more, they can be used repeatedly, the appearance is more attractive and the flavor is likely to be better. Jars differ in shape and in the method by which the cover or cap is held in place, after the contents has been processed, wide-mouthed jars are of advantage for most things, but particularly so for putting up whole fruits or vegetables, such as tomatoes or whole corn on the cob and so forth; they are easier to fill, easier to remove the con-tents from in good condition, and easier to wash.
Fig. 35 and 36 - There are several good types of jars and cans on the market. The shape and size should be chosen to accommodate the product which is to be put up. Wide-mouth jars and "sanitary top" cans are the most satisfactory for most purposes.
The majority of jars on the market are sealed by means of a rubber ring between the glass and the cap, which may be of glass, porcelain, or enameled metal. Both the quality of the rubber ring used and the evenness and surface finish of the glass and of the cover will affect the efficiency of the "seal" obtained. A leaky jar, no matter how small the leak may be, will eventually spoil. In one of the most modern types of jars, the rubber ring is dispensed with entirely, the seal being obtained by the use of a, composition sealing material, which comes already applied to an enameled lid, and is automatically melted and set in the processing and cooling of the jars. The cooling of the product inside of the jars creates a vacuum which holds the lid in place. The old-fashioned screw-top Mason jar has very largely been replaced by this type and by jars with the lid held in place by a clamp instead of a metal screw-band. whatever type of jar is used, it is false economy to buy a cheap jar which is not made of the best materials or is not accurately made.
Fig. 37- a - Cast iron steam pressure cooker, for use with pressure up to 30 pounds, b - Aluminum pressure cooker, much lighter and more convenient to handle.
Fig. 38 - A "water seal" canner, which will give a higher and steadier temperature than open kettle, a - container, with outer and inner wall; b - cover, with thermometer; c - rack for lifting jars or cans in and out.
Fig. 39 - A hand machine for putting on cork-lined metal-sealed caps. With one of these machines, bottles of all kinds can be utilized for pickles and preserves. The caps can be bought in assorted sizes, and a neat, tight, easy job is made of sealing.
Of tin cans there are three main types: those sealed with solder, and known as "solder top" cans; those on which the covers are sealed mechanically, known as "sanitary" cans; and those with covers sealed on by means of hot sealing-wax, known as "wax" tops. The latter have not been as satisfactory for general purposes, although suitable for acid vegetables and fruits.
Some fruits and vegetables which are particularly acid should be put in cans known as "enameled"; these have a coating on the inside which prevents, to some extent, the action of the acid of the product on the tin.
Cans are sold under standard sizes, as numbers 1, 2, 2 1/2, and so forth; the size and capacity corresponding to these numbers are as follows: