The manufacture of commercial grape-juice in America, to which country the industry is confined, began as a home practice following the fundamental processes of canning fruit. Toward the close of the last century, several inventive minds discovered methods of making a commercial product and began developing markets for their wares. The beginning of the present century found the new industry in full swing, since which time its growth has been truly marvelous. In 1900 the amount of grape-juice made in the United States was so small as to be negligible in the census report of that year. By 1910, the annual output had reached for the whole country over 1,500,000 gallons and at present writing, 1918, it is well above 3,500,000 gallons per annum.

The manufacture of grape-juice is no longer a home industry but a great commercial enterprise. It is an industry closely a.s.sociated with grape-growing, however, and as such needs further consideration here.

_Grape-juice regions._

The manufacture of grape-juice is centered in the Chautauqua grape-belt in New York, Pennsylvania and Ohio. So far, the demand seems to be almost wholly for juices made from native grapes, the juice of European grapes grown on the Pacific slope being so sweet as to be insipid. Possibly 80 per cent of the grape-juice now manufactured in America comes from a single variety, the Concord.

There can be no question, however, but that sooner or later grape-juices of distinct qualities will be made from many varieties of grapes, thus giving wider sale and greater variation for the product.

A very good sparkling grape-juice is now on the market and its reception seems to promise a great increase in the production of an article that closely simulates champagne in color and sparkling vivacity, but not, of course, in taste, since it contains no alcohol.

The grape-juice industry has been started and is in a flourishing condition in several other grape regions than the Chautauqua belt which is now its center. There are factories at Sandusky, Ohio, using grapes grown in the Kelly Island district; in southwestern Michigan there are several factories; and the industry still survives at Vineland, New Jersey, which probably should be called the original home of the manufacture of grape-juice. In the South, some grape-juice is made from Muscadine grapes, but this product seems not as yet to have been well received in the markets.

_Commercial methods of making grape-juice._

There is at present a great diversity of methods and of apparatus employed in the grape-juice manufacturing plants throughout the country. Since the industry is in its infancy, and the attempt has been made to hold some of the methods as trade secrets, the diversity of methods and appliances is not to be wondered at. No doubt there will be greater uniformity of method and machinery and, therefore, greater efficiency, as the industry develops.

Husmann[19] gives the following account of the manufacture of grape-juice in the eastern states and in California:

"Sound, ripe, but not over-ripe, grapes are used. These are first crushed or, in case the stems are to be removed, are run through a combined stemmer and crusher. If the machinery is stationed high enough, the crushed fruit can be run through chutes directly into the presses or kettles; otherwise, it must be pumped into them by means of a pomace or must pump or carried in pomace carts or tubs.

"If a white or light colored juice is desired, the crushed grapes are first pressed, the juice which comes from the press being heated to about 165 F., skimmed, run through a pasteurizer at a temperature of between 175 and 200 F. into well-sterilized containers, and then placed in storage.

"If a colored juice is desired, the crushed grapes are heated immediately, usually in aluminum kettles having double bottoms, which prevent the steam from coming in contact with the contents. These kettles usually contain revolving cylinders, the arms of which keep the crushed grapes thoroughly stirred while they are being heated to about 140 F. The simultaneous heating and stirring help to extract the coloring matter from the skins, tear the cells of the berries, increase the quant.i.ty of juice obtained per ton of fruit, and give to the must many ingredients of red wine, with the subst.i.tution of grape sugar for alcohol of the wine.

"The aluminum kettles are filled and emptied in rotation, thereby making continuous manipulation possible. The presses should be situated below the kettles, so that the hot juice can be drained directly into them. The expressed juice is then reheated to about 165 F., skimmed, and run through the pasteurizer in the same manner in which the white juice is handled. The juice pa.s.ses from the pasteurizer while still hot (about 160 F.) into the container, which should be sealed immediately. The lower the temperature (above the freezing point) at which these containers are then stored, the less is the danger of fermentation and the more rapidly the juice will clear and deposit its sediment.

"The ordinary receptacles in which the juice is stored are 5-gallon demijohns, 20-gallon carboys, or clean, new barrels or puncheons, well washed and drained. All containers should be thoroughly sterilized before they are filled, and the covers, corks, bungs, cloths, etc., used in sealing them should be scrupulously clean and carefully sterilized. If barrels or puncheons are used as containers, they are placed on skids and firmly wedged to prevent movement. As the juice cools, air laden with fermentation germs is apt to be drawn into the barrels by the decrease in the volume of the liquid. In order to prevent this, tight air-filtering plugs of sterilized cotton are sometimes used instead of the ordinary bungs of solid wood.

"The type of pasteurizer differs in almost every establishment. As the industry is of comparatively recent development commercially, there are few models on the market and each manufacturer has constructed the model best suited to his particular ideas or requirements. There are two general types, however, (1) open, double-bottomed kettles in which the juice is heated to the required temperature and then drawn off, and (2) continuous pasteurizers in which the juice is heated to the required temperature as it pa.s.ses through the water bath.

"The presses also show great variation in different establishments, either hydraulic, screw or lever power being used, and there is a marked difference between the types of pomace containers. Sometimes the crushed grapes are heaped on burlap cloths the sides of which are folded in, and these burlaps are placed one on top of the other in the press; sometimes press baskets take the place of these burlaps.

"The manufacturers in California and those in the grape-growing regions of the Rocky Mountains seem to have adopted entirely different methods of handling the juice after it is first pasteurized and stored. Most of the eastern juices are red and are obtained from the Labrusca varieties, generally the Concord. When the juice comes from the presses, some manufacturers strain it to remove the coa.r.s.e particles and then pour it directly into well-sterilized bottles; others siphon it off the sediment in the containers in which it is stored after the first pasteurization and pour it into pasteurized bottles. In either case, the bottles are securely corked and then repasteurized. The California juices, however, both red and white, are made exclusively from Vinifera varieties. They are allowed to settle in the original containers and are siphoned out of these and carefully filtered to make them clear and bright.

"The clearing of the juice is sometimes facilitated by fining or adding a small quant.i.ty of a substance which coagulates and when settling carries down with it the solid matters causing cloudiness in the liquid. Such finings may be applied at the time of the first pasteurization or just before the final filtration and bottling. In the latter case the juice is drawn off the settlings in containers, the finings are added, and the juice again pasteurized into other receptacles. When it clears, it is either bottled directly or first pa.s.sed through a filter, drawn into carefully sterilized bottles, securely corked, and then repasteurized. Care must be taken that the final sterilization is not at a higher temperature than the previous one; otherwise, solid matter may be precipitated and the must clouded again.

"A simple and efficient form of sterilizer consists of a wooden trough provided with a wooden grating which is raised 2 inches from the bottom and on which rest the filled bottles in wire baskets. The trough contains enough water to submerge the bottles and is kept at a temperature of 185 F. by means of a steam coil beneath the grating.

It requires about 15 minutes for the must at the bottom of the bottles to reach that temperature; for packages of other sizes it is necessary to make a test with a thermometer in order to determine how long it takes for the entire contents to reach 185.

"To prevent the corks from being expelled during sterilization, they are either tied down with a strong twine or with some contrivance such as the cork holder. In order that mold germs may not enter the must through the corks, especially if a poor quality of cork is used, the necks of the corked bottles are dipped in heated paraffin before putting on the caps, or the corks are sealed down with sealing wax. It is also well to keep the bottles on their rider to prevent the corks drying out."

_Home methods of making grape-juice._

The principles involved in making grape-juice in the home are the same as those used in canning. The grapes may be crushed by hand or in mills similar or identical with the small cider-mills owned by many farmers. In making a light-colored juice, the crushed grapes are put in a cloth sack and hung up to drain, or the filled sack may be twisted by two persons until the greater part of the juice is expressed. The juice is then sterilized in a double-boiler by heating it at a temperature of 180 to 200 F., care being taken that the thermometer never goes above 200. The sterilized juice is now poured into a gla.s.s or enameled vessel to stand for twenty-four hours, after which it is drained from the sediment and strained through several thicknesses of clean flannel. The juice is now put in clean bottles preparatory to a second sterilization, care being taken that at least an inch of s.p.a.ce is left at the top for the liquid to expand when heated. The second sterilization may be conducted in a wash-boiler or similar receptacle. The filled bottles must not rest on the bottom of the boiler but should be separated from it with a thin board. The boiler is filled with water up to within an inch of the tops of the bottles and heated until the water begins to boil. The bottles should then be taken out and corked immediately, using only new corks. After corking, the bottles are further sealed by dipping the corks in melted paraffin. A cheap corking machine is a great convenience in this work, and in any case the corks should be soaked for at least a half hour in warm but not boiling water.

The process varies somewhat in the making of red grape-juice. The crushed grapes are heated to a temperature of 200 F., and are then strained through a drip bag without pressure, after which the liquid is set away in gla.s.s or enamel vessels to settle for twenty-four hours. Except for this difference in the preliminary treatment of the juice, the methods are the same in making the red or the light-colored product. For proper keeping it is not necessary to let the juice settle after it is strained, but a clearer and brighter product is obtained if the juice is permitted to settle. In either case the grape-juice should keep indefinitely if the work has been well done.

As soon as bottles are opened, fermentation begins with the formation of alcohol.

RAISINS

The grape is best conserved as a raisin. Canning is seldom practiced with this fruit. A raisin is a dried grape. Tree-fruits are evaporated as by-products, but the raisin is a primary product. This is a difference worth noting; for with tree-fruits the cream of the crop goes to the fresh fruit market, while with the grape the entire crop of raisin varieties may go into the cured product. The raisin industry is dependent on a sunny and rainless climate and hence in America is confined to the grape regions of certain parts of California. In this state, raisin-making is a rich resource of the grape-grower, the annual output now averaging well above 200,000 pounds, grown on 120,000 acres of land, and having a market value of $10,000,000.

Fresno County, California, produces nearly 60 per cent of the output of the state and the city of Fresno is the center of the industry. The raisin industry does not stand alone in California, as some raisin grapes, notably Muscat of Alexandria, are good dessert sorts and are also much used for wine and brandy. Only the first crop of the variety named is used for raisins, while practically all of the second crop each season is made into wine and brandy.

Raisins proper are mostly made from the Muscat of Alexandria, although other large, white, sweet grapes are sometimes used. Sultana raisins, naturally seedless, are made from Sultanina and the Sultana. The dried currants of commerce are made from grapes, and of these California produces small quant.i.ties from White Corinth.

The following account of raisin-making is given by Husmann:[20]

"In the raisin districts grapes are ripe by the middle of August, the season often lasting into November. The average time necessary for drying and curing a tray of raisins is about three weeks, depending on the weather, the earliest picked grapes drying in ten days and the later ones often taking four weeks or more.

"The method of drying is very simple. The bunches are cut from the vines and placed in shallow trays 2 feet wide, 3 feet long, and 1 inch high on which the grapes are allowed to sun-dry, being turned from time to time by simply placing an empty tray upside down on the full one and then turning both over and taking off the top tray. After the raisins are dried they are stored away until they are packed and prepared for shipment. Some of the larger growers, in order not to run so much risk in drying on account of rain, and also to enable them to handle the crop fast enough, have curing houses, where the curing is finished after having been partially done outside."

_Dipping and scalding raisins._

"The operation of dipping and scalding is designed to accomplish several purposes, namely, to cleanse the fruit, to hasten its drying, and to give the dried fruit a lighter color. In dipping and drying, the fruit, immediately after being cut from the vines, is either dipped in clear water to first rinse it of particles of dust and other foreign matter, or it is taken direct to the scalder and immersed in a boiling alkaline mixture called 'legia' (lye) until the grapes show an almost imperceptible cracking of the skin, the operation consuming perhaps from one-fourth to one-half of a minute. This dipping calls for skill on the part of the operator, the duration of the emersion depending on the strength and temperature of the mixture and the condition of the fruit. Desiccation follows the scalding process, which is accomplished on trays in the sun, the same as undipped raisins cured entirely by solar heat. On account of the scald they cure rapidly, and the fruit is also often of lighter color when cured.

"The following formula has been used for Sultana and Sultanina grapes at Fresno:

"Fifteen pounds of 'Greenbank's 98-per cent lye' are boiled in 100 gallons of water. This mixture is for grapes containing 25 per cent of sugar. Should their sugar content be less, enough lye is added to remove the bloom and open the pores of the skin of the grapes. After dipping, the grapes are spread on trays and sulphured for 1 to 1-1/2 hours. Observation will show whether it may be necessary to vary this formula a trifle to suit conditions of ripeness and influence of temperature. The length of time required for dipping is ascertained by experience, and differs with the strength of the lye, the heat of the solution, and the thickness of the skins of the grapes."

_Packing raisins._

"The raisins as received at the packing house are weighed and the loose raisins and those that are to be shipped as dried grapes are immediately run through a stemmer and grader which stems, cleans, and a.s.sorts the raisins into three or four different grades, after which they are packed and shipped to various parts of the country, some also being exported. Those producing cl.u.s.ter or layer raisins (if they have not already been equalized) are first stored in the equalizing rooms.

In these rooms the sweat boxes, filled with layers of new raisins, are stacked and left usually from 10 to 30 days, or long enough for the overdried berries to absorb moisture from the under-dried ones. This sweating also properly softens and toughens the stems, which prevents their breaking and enables them to hold the berries better. In California, where the climate is so dry, no first cla.s.s pack could be made without thus first equalizing the raisins. After having been equalized the raisins are taken out, a.s.sorted into the different grades, and placed in trays holding 5 pounds each. The trays of the same grades are then pressed and stacked away in piles ready for packing.

"Pressing the raisins so that they look well and so none are burst open is work requiring experience and good judgment. It takes four pressed trays to fill a 20-pound box. The loose raisins that have dropped from the cl.u.s.ter through handling before they were equalized are also graded, the largest, of course, making the choicest pack."

_Cla.s.ses of raisins._

"Previous to the consolidated organization of the packers the three best grades of raisins on the stems were known as 'Imperial,'

'Dehesia,' and 'Fancy Cl.u.s.ters,' respectively. The California Raisin Growers a.s.sociation established cla.s.sification and grades similar to those of the Spanish raisin packers, on which the French trade names are also based. The original Spanish, as well as English terms with which they correspond, and the different grades in descending order of quality are shown in the following table:

========================================================================= SPANISH TERMS

FRENCH TERMS

ENGLISH TERMS

CALIFORNIA TERMS -------------+---------------+----------------------+-------------------- Imperial

Imperiaux Extra

Extra Imperial Cl.u.s.ter

Six-Crown Cl.u.s.ter Imperial Bajo

Imperiaux

Imperial Cl.u.s.ter

Five-Crown Cl.u.s.ter Royan Bajo

Royaux

Royal Cl.u.s.ter

Four-Crown Cl.u.s.ter Cuarta (4a)

Surchoix Extra

Choicest

Three-Crown Cl.u.s.ter Quinta (5a)

Choix Extra

Choice Cl.u.s.ter

Two-Crown Cl.u.s.ter =========================================================================

"The grading is optical, as a result of experience, there being no linear or cubic measurement standard. Thus, a nice cl.u.s.ter with all berries of large size, would be a 'Six-Crown Cl.u.s.ter,' such being the very finest raisins on the stem. 'Five-Crown Cl.u.s.ters' were formerly the 'Dehesia' cl.u.s.ter, and 'Four-Crown Cl.u.s.ters' were formerly 'Fancy Cl.u.s.ters.' Grades less than 'Four-Crown' on the stems (the 'Three-Crown' and 'Two-Crown') are known as 'Layers,' or 'London Layers.' These are placed in boxes containing 20 pounds net; in half boxes of 10 pounds; and quarter boxes of 5 pounds; and in fancy boxes containing 2-1/2 pounds. Loose raisins, or raisins off the stem, are graded into Two-Crown, Three-Crown, and Four-Crown raisins by being run through screens the meshes of which are thirteen thirty-seconds, seventeen thirty-seconds, and twenty-two thirty-seconds of an inch in size, respectively. The Sultanina (erroneously called Thompson Seedless), and the Sultana are packed in 12-ounce cartons, 45 to the case."

_Seeded raisins._

"The invention of a raisin-seeding machine by George E. Pett.i.t in the early seventies, and its use, has had a wonderful effect on the industry.

"Seeded raisins were first put on the market by the late Col. William Forsythe, of Fresno, Cal., who at first found it very difficult to dispose of 20 tons. The output in the last 15 years has increased from 700 tons to 50,000 tons per annum, and their popularity is constantly increasing. In 1900 about 14,000 tons were placed on the market, in 1905 about 21,000 tons, in 1910 about 31,000 tons, and in 1913 about 49,000 tons. The seeding machines in present use can turn out 300 tons per day. Seeded raisins are now the most important branch of the raisin industry.

"A brief outline of how seeded raisins are prepared will prove interesting. The raisins are first exposed to a dry temperature of 140 F. for three to five hours, after which they are put through a chilling process so that the pedicels can be easily removed, and are then thoroughly cleansed by being pa.s.sed through cleaning machines.

They are then taken by automatic carriers to another room, spread out on trays, and exposed to a moist temperature of 130 F. to bring them back to their normal condition. The raisins pa.s.s to the seeding machine, where they are carried between rubber-faced rollers and the impaling device of the seeding machine which catches the seeds and removes them from the fruits as they are flattened between the surfaces of the rollers. The impaled seeds are removed from the roller by a whisking device in such a way as to be caught in a separate receptacle. The seeded raisins pa.s.s through chutes to the packing tables on the floor below.

"The seeded or loose raisins are packed in 50-pound boxes; in 1-pound cartons, 36 to the case; in 12-ounce cartons, 45 to the case; and some in bulk in 25-pound boxes.

"Information has recently been sent out to the effect that the California a.s.sociated Raisin Co. is arranging to do away with the grades in seeded raisins, so there will only be one grade. This contemplates using all of the Three-Crown, the smallest of the Four-Crown, and the best of the Two-Crown in one blended grade.

"From the seeds, formerly used as a fuel, a number of by-products are now made.

"The seeds and pedicels removed from the raisins in seeding vary from 10 to 12 per cent of the original weight of the raisins according to their conditions and quality.