The book of ice-cream

Besides the milk products, a number of other materials are used in ice-cream. These are embodied in small amounts but their quality is of vital importance. For this reason they are briefly discussed.

29. Sugar.

—For sweetening the ice-cream, granulated sugar is usually employed. This may be either cane- or beet-sugar, and should be free from all visible dirt. Sugar seems to contain many mold spores and so should be examined to determine the presence of mold or bacteria. However, during the war, in order to conserve the supply of granulated sugar, various substitutes were used, such as corn sirup, invert sugar, honey and maple sirup.

30. Invert sugar.

—Ruehe⁠[14] gives the following directions for making invert sugar:

“Cane sugar (or beet sugar) can be inverted by the simple process of heating in the presence of an acid. The chemical reaction that takes place results in the same products being formed as are formed when the sugar (sucrose) is taken into the human body, the sugar forming equal parts of dextrose and levulose. The following formula may be used in making invert sugar syrup of such sweetness that a pound of the syrup will replace a pound of sugar:

These ingredients are mixed together and boiled for 30 to 35 minutes. If boiled longer than 35 minutes, the syrup darkens in color and a flavor develops which tends to make the syrup resemble glucose syrup, and this is somewhat undesirable. This solution boils at a temperature of about 221 degrees Fahrenheit. A steam pressure kettle can be used very satisfactorily or an open candy kettle over a steady fire may be used. If the solution is boiled too vigorously, there will be too large a loss by evaporation. Ordinarily the loss will be from 3 to 5 per cent.

“The above formula should make 140 pounds of syrup, and if there is considerable loss due to evaporation, the syrup can be brought up to this weight by the addition of water. The resultant invert sugar syrup is not unlike strained honey in appearance and taste. It contains about 71.4 per cent of sugar and it tastes considerably sweeter than a sugar syrup of the same strength. It does not crystallize, and it mixes readily with the ingredients of the ice cream. It can be used in the same proportions as sugar, the amount necessary for ten gallons of ice cream being 6.5 to 7 pounds. It gives very satisfactory results in freezing and a pleasant flavor in the finished product.

“It can be readily seen that by using the above method the sugar supply can literally be stretched, for with only 71.4 per cent as much sugar as is now being used in ice cream, the same degree of sweetness can be obtained.”

31. Sugar-saving substitutes.

—Frandsen,⁠[15] while working on sugar-saving substitutes, reached the following conclusions:

“1. Four formulas have been worked out which save from 30 per cent to 50 per cent of cane sugar in the mix:

“2. The ice cream prepared according to these four formulas meets the requirements of good ice cream.

“3. Corn syrup dissolves with difficulty in cold cream. When added to cream before pasteurizing, it dissolves readily.

“4. In hydrolyzing the syrups, excessive heating should be avoided.

“5. When invert sugar and corn syrup are used as the only source of sweetening, a rather noticeable syrupy flavor is imparted to the ice cream.

“6. When invert sugar, cane sugar and corn syrup are used in the proportions indicated in Formula No. 4, no objectionable flavor is noticeable.

“7. It is thought that hydrolyzing corn syrup in the presence of an acid will enhance its sweetening properties.

“8. In addition to saving cane sugar, all four formulas lower the cost of sweetening per gallon of ice cream.

“9. Corn sugar can replace 50 per cent of cane sugar in the mix.

“10. None of the substitutes so far tried will satisfactorily replace all the cane sugar in the ice cream mix.”

32. Cocoa and cocoa products.

—The various chocolate and cocoa preparations are manufactured from the bean of the tree Theobroma Cacao, of the family of Sterculiaceæ. This tree averages 13 feet in height, and its main trunk is from 5 to 8 inches in diameter. It is a native of the American tropics, being especially abundant and growing under best conditions in Mexico, Central America, Brazil and the West Indies.

The cocoa beans of commerce are derived chiefly from Ariba, Bahia, Caracas, Cayenne, Ceylon, Guatemala, Haiti, Java, Machala, Maracaibo, St. Domingo, Surinam and Trinidad. Besides these, the Seychelles and Martinique furnish a small amount.

The plant seeds, or beans, grow in pods, varying in length from 23 to 30 centimeters, and are from 10 to 15 centimeters in diameter. The beans, which are about the size of almonds, are closely packed together in the pod. Their color when fresh is white, but they turn brown on drying.

The gathered pods are first cut open, and the seeds removed to undergo the process of “sweating” or fermenting, which is conducted either in boxes or in holes made in the ground. This process requires great care and attention, as on it depends largely the flavor of the seed. The sweating operation usually takes two days, after which the seeds are dried in the sun until they assume their characteristic warm red color, and in this form are shipped into our markets.

33. Manufacture of chocolate and cocoa.

—For the production of chocolate and cocoa, the beans are cleaned and carefully roasted, during which process the flavor is more carefully developed, and the thin, paper-like shell which surrounds the seed is loosened and is very readily removed. The roasted seeds are crushed, and the shells, which are separated by winnowing, form a low-priced product, from which an infusion may be made having a taste and flavor much resembling chocolate.

The crushed fragments of the kernel or seed proper are called cocoa nibs, and for the preparation of chocolate they are finely ground into a paste and run into molds, either directly or after being mixed with sugar and vanilla extract or spices, according to whether plain or sweet chocolate is the end product.

For making cocoa, however, a portion of the oil or fat known as the cocoa butter is first removed, by subjecting the ground seed fragments to hydraulic pressure, usually between heated plates, after which the pressed mass is reduced to a very fine powder, either directly or by treatment with ammonia or alkalies, to render the product more soluble. It is held that the large amount of fat contained in the cocoa seeds (varying from 40 to 54 per cent) is difficult of digestion to many, such as invalids and children, and hence the desirability of removing part of the fat.

34. Composition of cocoa products.

—The chief constituents of the raw cocoa bean, named in the order of their relative amount, are fat, protein, starch, water, crude fiber, ash, theobromine, gum and tannin. In the roasting there is reason to believe a volatile substance is developed much in the nature of an essential oil, which gives to the product its peculiar flavor, and is somewhat analogous to the caffeol of coffee.

Tannin, the astringent principle of cocoa, exists as such in the raw bean, but rapidly becomes oxidized to form cocoa red, to which the color of cocoa is due.

35. Adulteration of cocoa products and standards of purity.

—The following are the United States standards: “Standard chocolate should contain not more than 3 per cent of ash insoluble in water, 3.5 per cent of crude fiber, and 9 per cent of starch, nor less than 45 per cent of cocoa fat.

“Standard sweet chocolate and standard chocolate coating are plain chocolate mixed with sugar (sucrose), with or without the addition of cocoa butter, spices, or other flavoring material, containing in the sugar and fat-free residue no higher percentage of either ash, fiber or starch than is found in the sugar and fat-free residue of plain chocolate.

“Standard cocoa should contain percentages of ash, crude fiber, and starch corresponding to those of plain chocolate, after correcting for fat removed.

“Standard sweet cocoa is cocoa mixed with sugar (sucrose) containing not more than 60 per cent of sugar, and in the sugar and fat-free residue no higher percentage of either ash, crude fiber, or starch than is found in the sugar and fat-free residue of plain chocolate.

“The removal of fat, or the addition of sugar beyond the above prescribed limits, or the addition of foreign fats, foreign starches, or other foreign substances, constitutes adulteration, unless plainly stated on the label.

“The most common adulterants of cocoa are sugar and various starches, especially those of wheat, corn and arrowroot. Starch is sometimes added for the alleged purpose of diluting the cocoa fat, instead of removing the latter by pressure, thus, it is claimed, rendering the cocoa more digestible and more nutritious. Unless its presence is announced on the label of the package, starch should be considered as an adulterant. Cocoa shells are also commonly employed as a substitute for, or an adulterant of, cocoa. Other foreign substances found in cocoa are sand and ground wood fibre of various kinds. Iron oxide is occasionally used as a coloring matter, especially in cheap varieties.

“Such adulterants as the starches and cocoa shells are best detected by the microscope. The presence of any considerable admixture of sugar is made apparent by the taste. Mineral adulterants are sought for in the ash.”

36. Chocolate sirup.

—Ice-cream may be flavored by pouring a chocolate sirup over it. The following materials are used in making the sirup:

Dissolve the gelatine in 10 pints of cold water, heat to the boiling point, then add 15 pounds granulated sugar, stirring occasionally until dissolved. Triturate 1 pound granulated sugar with the powdered cocoa and sodium chloride until thoroughly mixed, then add to the hot solution; boil for ten minutes, stirring constantly; strain while hot and when cool, add the vanilla.

37. Fruits.

—Many different fruits may be used to flavor ice-cream. The principal ones are pineapple, cherry, strawberry, raspberry, lemon, orange, peaches, and the like. In their season, the fresh ripe fruit is used as a flavoring. For the period when the fresh fruit cannot be obtained, the fruit may be canned, preserved without chemicals, preserved with chemicals, or dried. Only fresh ripe fruits should be employed, whether used fresh or held in some manner; since for ice-cream-making the fruit must be broken into small pieces, it is often cheaper to obtain from canneries small fruits or broken or crushed pieces.

In some of the large ice-cream plants the fruits are preserved in large jars (Fig. 6) by the addition of sugar and kept cold but not frozen. Fruits preserved in this way give the product a flavor similar to fresh fruits. Fruit extracts may be derived from the fruit, by fractional distillation in dilute alcohol. These extracts should not be confused with artificial or imitation flavors. The latter are often coal tar ethers or esters. In order to obtain the desired flavor, it is usually necessary to combine fruit extracts with the canned and preserved fruits.

38. Nuts.

—Only sound non-rancid nuts should be employed to flavor ice-cream. For flavoring, the nut meats should be blanched by soaking in hot water, and then removing the outer coating or covering; these blanched nuts should then be ground. Often broken nuts can be secured cheaply. A flavoring extract may be made from the nuts. In many respects this is desirable because a more pronounced flavor is obtained. For example, pistachio nuts give a very weak extract. It is the custom to use pistachio flavoring and color the ice-cream green.

39. Stabilizers and fillers.

—If ice-cream is not consumed as soon as made, ice crystals will begin to form unless some stabilizer is used. This is a substance added to ice-cream to prevent the formation of ice crystals which cause a grainy bodied product. Stabilizers are sometimes known as “holders” or “colloids” and commonly as “binders.” A “filler” is some substance added to the ice-cream to cheapen it, usually to replace the milk-fat and milk solids not fat. A “filler” may serve the purpose of a “binder” or a “stabilizer,” but a stabilizer cannot take the place of a “filler.” The common stabilizers are gelatine and gum tragacanth. The common fillers are the various starches, such as cornstarch, rice flour, arrowroot, wheat flour, eggs, an excess of gelatine and the like.

40. Gelatine.

—Commercial gelatine is an animal product made from bones, hides, skins, tendons, horn piths, tannery trimmings and any kind of connective tissue from the animal’s body. Pure gelatine is an amorphous, more or less transparent substance of vitreous appearance. It is brittle when dry, free from color, taste and smell. Gelatine and glue are manufactured from the same materials, more care being used in making gelatine.

The detail process of making gelatine varies in the different factories, but the general steps are as follows: Treating and cleaning the raw material; dissolving gelatine; concentrating; chilling and spreading; drying; finishing; including grinding and packing. Gelatine is put on the market in sheet, flake, shredded and powdered form. If made from clean materials, no objection can be raised against its use as a food. Gelatine swells in cold water, absorbing five to ten times its weight of water. This is sufficient water to dissolve it at a temperature of 85° F. to 90° F. The strength or gelatinizing power of different samples of gelatine varies within wide limits. The following is a simple method to compare different gelatines: Take ten grams of the sample and soak over night in 100 cubic centimeters of cold water. The next morning dissolve the gelatine at a temperature of 80° C. First note the odor. It should not be pronounced or disagreeable. Determine length of time it takes for a 50 cubic centimeter pipette full to run out. Note the time it takes to gelatinize. Test the strength with a jelly tester which is a simple arrangement to determine the weight necessary to force a plunger into the gelatine.

41. Preparing gelatine for use in the ice-cream.

—In order to utilize gelatine in ice-cream, it must be brought into solution. A steam-jacketed copper kettle is usually employed for heating the gelatine (Fig. 7). If a smaller quantity is taken or a special gelatine cooker is not available, a double boiler or a can set in water can be used. Whatever utensil is selected to cook the gelatine, it should be kept clean. In many ice-cream factories, the gelatine cooker is badly neglected. Before the gelatine is heated, it should be soaked in cold water. One pound of gelatine should be put into about eight quarts of water. Some prefer to use milk instead of water. The gelatine should be stirred into the water rather than the water poured on to the gelatine. This will to a large extent eliminate the formation of lumps which would require excessive heating to break them down. The gelatine should be soaked from twenty to thirty minutes in cold water before the heat is applied. This soaked or soft gelatine should then be placed in a water-jacketed heater and heated to a temperature of 165° F. to 170° F. In case the gelatine is soaked in milk, it should not be heated above 145° F. A higher temperature is very liable to give it a cooked or scorched flavor. At this lower temperature, it is advisable to hold it ten or fifteen minutes to make sure that the gelatine is all broken down. It is necessary to heat the gelatine to the temperature mentioned above to secure the best results. The eye cannot determine when the gelatine is all broken down. There is danger of over-heating; it should not be held at high temperature for long periods of time nor allowed to boil. In putting the gelatine into the mix, it should be done at the above mentioned temperatures for dissolving; not all at one time, but poured in slowly and with as rapid agitation of the mix as possible, and it will distribute itself more evenly before it has time to congeal. A good gelatine will jelly at a temperature of 85° to 90°, according to the proportions used; so that when pouring gelatine into a mix with a temperature probably of 45° or 50°, it is very liable to harden and make the ice-cream lumpy.

42. Gum tragacanth.

—This is a compound gum obtained from a shrub, a species of Astragalus. In July or August the leaves are stripped from the shrub and a hole made in the bark. The shape of the hole regulates the form of the gum, a longitudinal cut making the leaf or flake form, a puncture the thread form, and an irregular hole a knob-like mass. The gum is gathered by the natives. Dry weather gives a whitish colored gum which is best; wet and dusty weather give an inferior yellowish gum.

Gum tragacanth will absorb fifty times its weight of water. For use in ice-cream, the gum is soaked in water, one ounce of gum absorbing two quarts of water. At least twenty-four hours should be allowed for this absorption. Before being put in the ice-cream, the mixture should be strained to remove any lumps. If it is not all to be used as soon as soaked, a gum stock may be prepared by adding sugar at the rate of two pounds for each quart of water. This will act as a preservative. Gum tragacanth is odorless and tasteless. Just how it acts as a binder is not known.

43. Other substances used as binders.

—Two plants, Irish and Iceland moss, are sometimes used as binders. The former is a sort of algæ and the latter a lichen. They are both very low in food value.

44. Eggs.

—In some kinds of ice-cream, eggs are necessary to give the characteristic body and texture. When eggs are employed, it is usually as a filler, since it is possible to reduce the percentage of either the milk-fat or milk solids not fat or both. The usual practice is to separate the yolks and whites of the eggs. The yolks are cooked with the cream if used and the whites beaten and added just before the ice-cream is frozen. Eggs usually give ice-cream a smooth texture and a firm body. They also impart a characteristic flavor.

45. Starchy fillers.

—Several starchy substances, such as cornstarch, rice flour, arrowroot and wheat flour, are sometimes used in large quantities and so become fillers. They give a characteristic starchy flavor to the ice-cream. They are often employed to cheapen the product. The starches are ordinarily cooked before using but sometimes are mixed with the sugar and used without cooking.

46. Prepared ice-cream powders.

—A large number of prepared substances, both powders and liquids, is on the market. These are often used in the place of some other binder. They may contain any or all of the materials previously mentioned, and in addition they often contain sugar to give both bulk and weight. These powders are usually added to the ice-cream by mixing with the sugar. Many times, in proportion to the results obtained, they are found to be expensive.

47. Rennet.

—Another binder is some form of rennet. Its use is not common and is ordinarily in combination with other materials.