Drying

“ Drying Appliances.—The stiff paste or cakes from the hydro-extractor or filter-press can be shaped, but require to be dried before they are put on the market. Drying is a wearisome operation, the finely divided material taking a very long time to dry completely, even during the summer months, whilst in winter it is almost impossible to get certain colours—such as ferric oxide colours and levigated clay—quite dry in the air, the inside of the lumps remaining soft and pasty after lying for months. ”

“ One of the great secrets in all drying operations is to have a constant current of fresh hot air playing on the goods to be dried, this absorbs the moisture they contain, and the water-charged air thus produced must be taken away as quickly as possible. ”

“ The effect produced by the two drying processes is very different: when dried by artificial heat, the exterior of the pieces becomes hardened before the interior has entirely lost its moisture, and consequently the pieces decay in the centre, although the surface may show no change. ”

“ When the drying is done in a dry atmosphere the surface quickly dries and hardens, and the moisture from the interior passes to the surface as vapour, the soluble salts being left distributed through the whole mass, and consequently no “scum” is produced. ”

“ The more quickly the drying can be accomplished the better. For this reason, settled dry weather should be chosen for this kind of work; if windy, all the better.
165. Family Washing.— [The following method, though not generally known, is much practiced in many families.] Melt together half a pound each of washing soda and of soap cuttings, mix well with sixteen gallons of water, pour it lukewarm over the dirty linen, and leave to soak for twenty-four hours. ”

“ When the operation of drying is going on largely, some of the pans in the range are used for finishing the process, while others, and the hottest ones, are heating and moistening the leaves before they are squeezed and rolled. ”

“ In the application of any of these drying methods, however, it is important to note that the more surface of food there is exposed, the more quickly will evaporation take place. Drying should therefore be done on devices constructed in such a way that air may pass up through food, as well as across its surface. In drying foods, the racks should be turned frequently, so that all parts will be exposed equally to the heat or the currents of air. Also, the food must be turned over often, in order that all parts will dry evenly. ”

“ It has been imagined that sun and wind alone dry clothes but the fact is that air is the drying medium and therefore the best dryers provide a good circulation of air plus heat. Dry air has a tremendous love for moisture and eats it up as a blotter eats up ink. The warmer the air the more moisture it will hug. This would seem enough, just to bake the clothes, but baking does not remove odors and does render them yellow; they are unventilated and smell like the laundry, so people are prone to say “Sun drying or nothing.” ”

“ From the rafters of the roof of the Drying House are suspended in bunches all the herbs that the grower cultivates. To accelerate the desiccation of rose leaves and other petals, the Drying House is fitted up with large cupboards, which are slightly warmed with a convolving flue, heated from a fire below. ”

“ DRYING is one of the simplest and cheapest ways of preserving fruits and vegetables for future use. Food may be dried by the sun or by artificial heat. If dried in the sun, protection from dust must be given, and food must be put under cover in the evening before the dew falls. Spread the prepared fruit or vegetable on frames covered with coarse wire netting or cheese-cloth and put in the sun for successive days until the product is sufficiently dried. Artificial drying is quicker and cleaner than sun drying, especially in moderate and cold climates. ”

“ The drying room, or box, as the case may be, must be kept cool, and if any current of air is induced it should be cool and constant, so that the drying may proceed with perfect regularity until the process is complete. ”

“ Most food products release moisture rapidly during early stages of drying. This means they can absorb large amounts of heat and give off large quantities of water vapor while remaining at a temperature well below that of the drying air. Maximum drying rates can be achieved by providing a larger, thermostatically-controlled heat source and a fan for circulating air. ”

“ In drying chemicals or fabrics, all that is required is to provide heat enough to vaporize the moisture and circulation enough to carry off the vapor thus secured, and the quickest and most economical means to these ends may be used. While on the other hand, in drying wood, whether in the form of standard stock or the finished product, the application of the requisite heat and circulation must be carefully regulated throughout the entire process, or warping and checking are almost certain to result. ”

“ The drying trays are sometimes distributed through the orchard or vineyard, thus drying the fruit with as little carrying as possible. Others clear off a large space outside the plantation and spread the trays where full sunshine can be obtained. Drying spaces should be selected at a distance from traveled roads, to prevent the deposit of dust on the fruit * * *.
Grading.—It is of great advantage in drying to have all the fruit on a tray of approximately the same size, and grading before cutting is advisable. Machines are now made which accomplish this very cheaply and quickly. ”

“ Like all fruits, they are better for quick drying by artificial heat. The French prunes, the process of drying which is minutely described by Downing in his fruit-book, are no better than our best varieties, quickly dried by artificial heat in a dry house, or moderately-heated oven. ”

“ Another invention, of which we have as yet heard little definite in England, consists in drying at a low temperature by air artificially deprived of its moisture. This may be accomplished in several ways. Experiments have been made in drying in a closed chamber provided with trays of calcium chloride to absorb the moisture evaporated. Air when artificially cooled by compression and subsequent expansion, as in the case of ice-making machines, parts with a large portion of its moisture, which is condensed in the form of ice in the tubes of the machine. ”

“ Thus cleansed, the wool is delivered by rollers to the drying machines, where hot air and great fans are now utilized to extract all the moisture without tearing the fiber. The ventilation—drying of wool by means of hot air—effects the object in one tenth of the time occupied by the old method of drying by exposure in the open air. So enormous has been the increase in the production of wool, stimulated in all quarters of the globe by the enlarged capacity for its manufacture ”

“ Before satisfactory methods of canning came into use, drying was a common method of preserving both fruits and vegetables, and while it has fallen into disuse to a great extent in the home, much may be said for its value. Drying consists merely in evaporating the water contained in the food, and, with the exception of keeping it dry and protected from vermin, no care need be given to the food in storage. ”

“ The proper drying of vegetable substances, is of the greatest importance. It is often directed to be done in the shade,138 and slowly, that the volatile and active particles may not be dissipated by too great heat. But this is an error; for they always lose infinitely more by slow than by quick drying. ”

“ The temperature of the drying-room requires careful regulation, and should never be allowed to rise above 68° to 77° F., as otherwise the glue would soften and run through the meshes of the net, or adhere so firmly to the twine as to require the nets to be put in hot water for its separation. Dryness of air is of far greater importance in the drying process than a high temperature. To promote this dryness of air and prevent the aqueous vapor from condensing, evaporating, and again condensing upon the cold walls of the room, they are wainscoted. ”

“ Drying. When the steeping is finished the limestone is taken out to be dried. Small objects may be placed upon a glass ring, wooden tripod or some such appliance, which admits air on all sides, and may thus be dried by the air only. A piece of paper laid loosely over them will protect them from dust. In winter a hot stove, or similar source of heat, affords a satisfactory method of drying, but wet stones must not of course be placed directly upon the hot iron stove plate [68] lest spots of rust should be produced upon the stone. ”

“ The drying of food is simple, and no elaborate equipment is required for carrying out the process. Dried food requires less space and care in storage than food preserved in any other way, and both paper and cloth containers may be used in storing it. When storage space is limited, or when there is a very large quantity of some such food as apples or string beans that cannot be used or canned at once, it is advisable to dry at least a part of them. When used in combination with canning, drying offers an excellent means of preserving foods and thus adding to their variety. ”

“ Also, if the quantity of surface remains the same, the time of drying will be proportioned to the quantity of matter; as the greater the quantity of matter under the same surface, the longer it will be in drying. ”

“ The trays should be shifted during the drying process to procure uniformity of drying.
Several types of stove dryers are on the market. One of these has a series of trays in a framework, forming a compartment. This is placed on top of the stove. Another is a shallow metal box which is filled with water. This is really a water-bath dryer. This dryer or dehydrator can be used on either a gas or coal range. A thermometer is necessary in order to maintain the right temperature. The slices of vegetables or fruit are placed on the tray with the thermometer, and the dryer does the work. ”

“ During the drying process, if the temperature or the amount of moisture or the access of air is not kept in a proper condition, various troubles arise and various diseases make their appearance, which either injure or ruin the value of the product. ”

“ If a patent drier is used, regulate the heat with a thermometer according to the time-table for drying. Turn the product while drying when necessary to keep it from adhering to the pan and make sure that every portion is subjected to heat. Quick drying is preferable to slow drying, but the heat must not be sufficient to cook the product. ”

“ Drying of animal fibre.—The best mode of operating is as follows:—The flesh must be cut into slices from 2 to 6 ounces in weight, immersed in boiling water for 5 or 6 minutes, and then laid on open trellis-work in a drying-stove, at a temperature kept steadily about 122° F., with a constant stream of warm dry air. That the boiling water may not dissipate the soluble animal matters, very little of it should be used, just enough for the meat to be immersed by portions in succession, whereby it will speedily become a rich soup, fresh water being added only as evaporation takes place. ”

“ The water in food that is to be dried may be evaporated by applying heat, by bringing the food in contact with moving air, or by subjecting it to a combination of both of these methods. The heat for drying may be obtained from the sun, as in the sun-drying method, or from the stove, as in the stove-drying method, while moving air for evaporating moisture may be obtained from an electric fan, as in the electric-fan drying method. ”

“ In most cases it is found sufficient to roll crepe thin for air-drying in order to prevent the appearance of coloured spots. It is found, however, that some drying-houses are so badly planned and constructed, that quick drying under even the best of conditions is a practical impossibility. ”

“ For sun drying of fruits and vegetables, the simplest way is to spread the slices or pieces on sheets of plain paper or lengths of muslin and expose them to the sun. Muslin is to be preferred if there is danger of sticking. Trays may be used instead of paper or muslin. Sun drying requires bright, hot days and a breeze. Once or twice a day the product should be turned or stirred and the dry pieces taken out. The drying product should be covered with cheesecloth tacked to a frame for protection from dust and flying insects. ”

“ Products dried in a sun drier, no matter how crude, are superior to those dried in the open without protection of some kind. Products dry more rapidly in high altitudes than at sea level.
Racks in oven can be used. Plates or platters can be used in oven. A stove drier hung over the stove can be used. A water-bath or other commercial drier can be used with the stove.
TIME-TABLE FOR DRYING FRUITS
CHAPTER XIV HOW TO DRY VEGETABLES
Vegetable drying is a little more complicated than fruit drying, just as vegetable canning is more complicated than fruit canning. ”

“ Being covered with canvas, etc., every night, the heat is preserved, and every morning, when the sun rises, the grapes are yet warm. The drying on such beds has never, in fact, been interrupted. The drying-floors are also useful in case of too hot weather, when the grapes can be properly sheltered with canvas and prevented from being cooked; when finally dried, the covering, again, will serve to keep the moisture from too quickly evaporating. ”

“ Crepe may Increase in Weight.—As an instance of the kind of result obtained a graph is here given of the rate of drying of a batch of pale crepe. This was hung to dry in the top room of a drying-house in which rubber ordinarily dries quickly. The rubber was hung in a good position, with the bulk of output, near a window which was open for some time during the day. In order to restrict the day interval of drying to the actual period in which the sun was likely to be in evidence, the day was taken to begin at 8 a.m. ”

“ Since air circulation is as essential as the proper degree of heat, and as its contact with the material to be dried depends upon its free circulation, it is necessary that the dampers for its admittance into, and its exit from, the drying room be efficiently and properly operated. ”