This section is from the book "The Standard Cyclopedia Of Horticulture Vol2", by L. H. Bailey. See also: Western Garden Book: More than 8,000 Plants - The Right Plants for Your Climate - Tips from Western Garden Experts.
The domestic operation of drying fruit has been practised ever since men looked beyond their immediate wants and stored food for time of greater need. Dried fruit has long been an article of commerce, yet until a few years ago only the most primitive methods were used in drying, and the industry, commercially, was confined to a few favored regions in Europe. The modern industry is not yet a half-century old. Its almost inconceivable growth in America in this brief time is one of the industrial phenomena of the times. Spurred into activity by the encroachment of American products in their markets, the European producers, by the adoption of better methods, and by governmental encouragement, have increased greatly their output of dried fruit. Thus, from an adjunct to fruit-growing for home use, drying fruit has become, within recent years, one of the main branches of horticulture.
An idea of the dried-fruit industry in the United States and of its great growth in recent years may be obtained from the following figures from the census of 1910 for the crop of 1909: start the evaporation of large fruits at a low temperature and finish at a high one, but with berries the reverse is true.
Recently two or three patented processes for curing fruit by "dehydration" have been introduced with much promise of betterment in the industry. While the machinery, the methods and the products are quite different in evaporating and dehydrating, the principle in the two operations is practically the same. In both processes the water is removed from the fruit by moving currents of warm air. In evaporation the air is warmed only. In dehydration the air is dried by cooling until the moisture is condensed out and is then warmed and passed over the fruit or vegetable to be cured. By the new process much time is saved and a greater variety of fruits and vegetables can be used.
The following are definitions of the somewhat technical terms used in the industry: Bleaching is the process of changing the dark color of fruit to a lighter hue, or of preventing the discoloration; it is generally accomplished by sulfuring. Bloaters are prunes which in drying swell up to an abnormal size; they are usually produced by fermentation in over-ripe fruit. Chops are dried apples cured without paring or coring to be used in making cider or vinegar. Dipping is the process of cutting the skin of fresh prunes to facilitate curing. The operation is performed by submerging the fruit in boiling lye. Cured fruit is sometimes dipped in one of various solutions as a "finishing" process. Drip is the syrupy liquid which oozes from prunes in the process of evaporation; it generally characterizes a poor prune or a poor evaporator. Frogs are cured prunes having an abnormal shape, a condition caused by curing unripe fruit. Pricking is the process of puncturing the cuticle of fresh prunes. It is done by means of a machine, the essential part of which is a board covered with projecting needles, over which the prunes must pass. It accomplishes the same end as lye-dipping. Sizes is a term used to indicate the number of cured prunes it takes to make a pound.
The "four sizes" known in the markets are 60's-70's, 70's-80's, 80's-90's, 90's-100's. Sugaring is the formation of globules of sugar on the cuticle of cured prunes or raisins. Sulfuring is a process to which fruit is subjected to give it a lighter color. The fruit is exposed to fumes of burning sulfur before being exposed to the sun or put in evaporators. Sweating is a process to which cured fruit is subjected before packing; it is put in a room at a high temperature and allowed to become moist. Waste is a dried product made from skins and cores of apples and pears and used for vinegar. Apples and pears are peeled, cored, cut into rings and bleached by being exposed to the fumes of sulfur for about a half hour in preparation for drying or evaporating. Fruits so prepared are placed upon trays for sun-drying and must be cured in the sun for three to five days- In evaporating in the western states, the prepared fruits are placed on trays and passed in from six to twelve hours through the evaporator chamber, but in the East, where the product is chiefly made, the prepared fruit is piled from 4 to 6 inches deep on the floor of a kiln.
Here it is left for fourteen to sixteen hours, being turned every two or three hours, until the fruit is no longer sticky, an indication that it has reached the proper stage of dryness. In New York, the law requires that evaporated apples contain not more than 27 per cent of moisture. One hundred pounds of apples will yield from twelve to fifteen pounds of evaporated apples.
Apricots, peaches and nectarines must be fully ripe before drying and without bruises. They are pitted, and may or may not be peeled. If peeled, the operation is done with a machine or with lye, though the use of the latter is considered bad practice. The fruit is placed on the trays cup side up. About three days are required for drying in the sun and about eight hours
All other fruits......
Adding the valuations given, results in a grand total of $19,840,395 for dried fruits in the year 1909. Comparing this sum with the census of 1900, one finds that the crop in 1899 was valued at $4,757,005 and that the industry, judged by the figures, has increased more than fourfold in ten years.
Fruit may be cured in the sun, or it may be cured in drying-machines, called evaporators. That cured in the sun is called by the producer "dried fruit;" that in evaporators, "evaporated fruit." By far the larger part of the world's product is cured in the sun. Thus, at least three-fourths of the fruit dried in America is sun-dried in California.
In countries having a sufficiently warm and dry climate, as Greece and Turkey, and parts of France, Spain and western America, fruit is dried almost wholly in the sun. The fact that in these favored localities the drying capacity is limited only by the acreage of sunshine, makes it certain that the proportion of sun-dried fruit will always be vastly greater than that of evaporated fruit. Drying fruit in the sun is a simple process, but one hedged in by many little arts and methods that facilitate the work and improve the product. In general, the process is as follows: The fruit is graded, bleached by sulfur, if a light-colored product is desired, in the case of prunes dipped or pricked, and is then spread on trays to be exposed to the sun. When the drying process is completed, the fruit is again graded, in most cases put through a sweat, and then "finished" in various ways, as by dipping or glossing.
There are many styles of evaporators, but all possess in common a chamber for the reception of the fruit, through which a current of warm air is forced, or the fruit is forced through the air, or both, the object being to remove the aqueous matter from the fruit as quickly as possible, and the principle being that warm air will absorb more moisture than cool air. The saturated air must not remain in contact with the fruit. Since different fruits exact different conditions, it is necessary to change the temperature and velocity of the air-current in the drying-chamber at will. To make the product homogeneous, current and temperature must be equal in all parts of the evaporator. It is obvious that simplicity in the machine and economy in heat and in room are cardinal virtues in a good evaporator. It is the rule to for evaporating. The cured product should be of a translucent amber color.
Berries are seldom sun-dried for the markets. For evaporating they are placed on trays in quantities of sixteen to thirty quarts, given a temperature of about
175° at the start, and are finished in four to five hours, at a temperature of about 100°. After being taken from the evaporator, they are piled for sweating in a warm, ventilated room.
Figs for drying must be gathered when fully ripe. Some growers prefer drying in shade rather than in sun. Evaporators are seldom used. The fruit is not allowed to dry hard, and before packing must be well sweated. Usually, for "finishing," they are dipped in salt water or syrup. The drying process requires from five to eight days.
Prunes are allowed to ripen until they fall to the ground. Before being spread on the trays they are dipped or pricked in order to thin or crack the skin, that the moisture may easily escape, and dripping be prevented. Sun-drying requires from one to three weeks, while from twelve to thirty hours are required for evaporation. A thorough sweat prevents the sugaring so common to this fruit. Before packing they are graded in sizes. Dipping as a "finishing" process is practised by many producers. A good prune is soft, smooth and meaty, with loose pit, and of an amber, dark red or golden hue, depending upon the variety.
Grapes for raisins are sun-dried. They must be picked when fully ripe, the bunches, and the berries on the bunches, being sorted as the picking progresses. The operation of drying must be watched with care. The process requires from eight to fourteen days, during which time the bunches must be turned at least once. A sweat is given before packing. Raisins are graded into half a dozen or more brands for the market. U P. Hedrick.