Vinegar, when properly made, should remain clear, and should not form a heavy deposit or produce any large amount of the fungous growth, commonly called the "mother" of vinegar. In order to prevent the vinegar from becoming cloudy and forming deposits, it should be strained and stored in clean jugs and protected from the air. So long as air is excluded further acetic acid fermentation and production of "mother" of vinegar cannot take place. When the vinegar is properly made and the fermentation process has been completed, the acid already produced prevents all further development of acetic acid ferments. When vinegar becomes cloudy and produces deposits, it is an indication that the acetic fermentation has not been completed.
The national standard for pure apple cider vinegar calls for not less than 4 grams acetic acid, 1.6 grams of apple solids, and 0.25 grams of apple ash per 100 cubic centimeters, along with other characteristics, as acidity, sugar, and phosphoric acid content. Many states have special laws regarding the sale of vinegar.
203. Adulteration of Vinegar.—Vinegar is frequently adulterated by the addition of water, or by coloring spirit vinegar, thus causing it to resemble cider vinegar. Formerly vinegar was occasionally adulterated by the use of mineral acids, as hydrochloric or sulphuric, but since acetic acid can be produced so cheaply, this form of adulteration has almost entirely disappeared. Colored spirit vinegar contains merely a trace of solid matter and can be readily distinguished from cider vinegar by evaporating a small weighed quantity to dryness and determining the weight of the solids. Occasionally, however, glucose and other materials are added so as to give some solids to the spirit vinegar, but such a vinegar contains only a trace of ash[[18]]. Attempts have also been made to carry the adulteration still further by adding lime and soda to give the colored spirit vinegar the necessary amount of ash. Malt, white wine, glucose, and molasses vinegars when properly manufactured and unadulterated are not objectionable, but too frequently they are made to resemble and sell as cider vinegar. This is a fraud which affects the pocketbook rather than the health. For home use apple cider vinegar is highly desirable. There is no food material or food adjunct, unless possibly ground coffee and spices, so extensively adulterated as vinegar.
Vinegar has no food value whatever, and is valuable only for giving flavor and palatability to other foods, and to some extent for the preservation of foods. It is useful in the household in other ways, as it furnishes a dilute acid solution of aid in some cooking and baking operations for liberating gas from soda, and also when a dilute acid solution is required for various cleaning purposes.
Vinegar should never be kept in tin pails, or any metallic vessel, because the acetic acid readily dissolves copper, tin, iron, and the ordinary metals, producing poisonous solutions. Earthenware jugs, porcelain dishes, glassware, or wooden casks are all serviceable for storing vinegar.
204. Characteristics of Spices.[[70]]—Spices are aromatic vegetable substances characterized as a class by containing some essential or volatile oil which gives taste and individuality to the material. They are used for the flavoring of food and are composed of mineral matter and the various nitrogenous and non-nitrogenous compounds found in all plant bodies. Since only a comparatively small amount of a spice is used for flavoring purposes, no appreciable nutrients are added to the food. Some of the spices have characteristic medicinal properties. Occasionally they are used to such an extent as to mask the natural flavors of foods, and to conceal poor cooking and preparation or poor quality. For the microscopic study of spices the student is referred to Winton, "Microscopy of Vegetable Foods," and Leach, "Food Inspection and Analysis."
205. Pepper.—Black and white pepper are the fruit of the pepper plant (Piper nigrum), a climbing perennial shrub which grows in the East and West Indies, the greatest production being in Sumatra. For the black pepper, the berry is picked before thoroughly ripe; for the white pepper, it is allowed to mature. White pepper has the black pericarp or hull removed. Pepper owes its properties to an alkaloid, piperine, and to a volatile oil. In the black pepper berries there is present ash to the extent of about 4.5 per cent, it ought not to be above 6.5 per cent; ether extract, including piperine and resin, not less than 6.5 per cent; crude fiber not more than 16 per cent; also some starch and nitrogenous material. The white pepper contains less ash and cellulose than the black pepper. Ground pepper is frequently grossly adulterated; common adulterants being: cracker crumbs, roasted nut shells and fruit stones, charcoal, corn meal, pepper hulls, mustard hulls, and buckwheat middlings. The pepper berries wrinkle in drying, and this makes it difficult to remove the sand which may have adhered to them. An excessive amount of sand in the ash should be classed as adulteration. Adulterants in pepper are detected mainly by the use of the microscope. The United States standard for pepper is: not more than 7 per cent total ash, 15 per cent fiber, and not less than 25 per cent starch and 6 per cent non-volatile ether extract.[[71]]
206. Cayenne.—Cayenne or red pepper is the fruit pod of a plant, capsicum, of which there are several varieties,—the small-fruited kind, used to make cayenne or red pepper; and the tabasco sort, forming the basis of tabasco sauce. It is grown mainly in the tropics, and was used there as a condiment before the landing of Columbus, who took specimens back to Europe. Cayenne pepper contains 25 per cent of oil, about 7 per cent of ash, and a liberal amount of starch. The adulterants are usually of a starchy nature, as rice or corn meal, and the product is often colored with some red dye.
207. Mustard.—Mustard is the seed of the mustard plant, and is most often found in commerce in the ground form. The black or brown mustard has a very small seed and the most aroma. White mustard is much larger and is frequently used unground. For the ground mustard, only the interior of the seed is used, the husk being removed in the bolting. Mustard contains a large amount of oil, part of which is usually expressed before grinding, and this is the form in which spice grinders buy it. In mustard flour there is: ash from 4 to 6 per cent, volatile oil from 0.5 to 2 per cent, fixed oil from 15 to 25 per cent, crude fiber from 2 to 5 per cent, albuminoids from 35 to 45 per cent, and a little starch. The principal adulterants are wheat, corn, and rice flour. When these are used, the product is frequently colored with turmeric, a harmless vegetable coloring material.
208. Ginger.—Ginger is the rhizome or root of a reed-like plant (Zingiber officinale), native in tropical Asia, chiefly India. It is cultivated in nearly all tropical countries. When unground it usually occurs in two forms: dried with the epidermis, or with the epidermis removed, when it is called scraped ginger. Very frequently a coating of chalk is given, as a protection against the drug store beetle. Jamaica ginger is the best and most expensive. Cochin, scraped, African, and Calcutta ginger range in price in the order given. Ginger contains from 3.6 to 7.5 per cent of ash, from 1.5 to 3 per cent of volatile oil, and from 3 to 5.5 per cent of fixed oil. There is a large amount of starch. The chief adulterants are rice, wheat, and potato starch, mustard hulls, exhausted ginger from ginger-ale and extract factories, sawdust and ground peanut-shells, and turmeric is frequently used for coloring the product. The United States standard for ginger is not more than 42 per cent starch, 8 per cent fiber, and 6 per cent total ash.[[71]]