This section is from the book "A Treatise On Beverages or The Complete Practical Bottler", by Charles Herman Sulz. Also available from Amazon: A Treatise On Beverages.
When inferior grades or raw sugar in exceptional cases are used, the hot syrup process must be employed by all means, in order to refine the sugar. In this case add to the mixture of sugar and water some granulated animal charcoal, which acts as decolorizer, purifier and clarifier, and also neutralizes the alkalies, (about one pound to twenty pounds of sugar). Bone-black (charcoal-dust) should never be used, since it is impossible to be removed from a syrupy liquid by filtration, unlesc much diluted. Also add some patent (artificial or blood) albumen to about twenty pounds of sugar, or the white of an egg, and mix well. Then without further agitation heat rapidly. The albumen coagulates at about 70° C. (158° F.), rises to the top, attracting and enveloping dirt and other foreign substances that are always present in raw sugar, and which are skimmed off with a ladle or filtered out. Some raw sugars may have become viscous or acidulous and are more difficult to clarify. It is proper under such circumstances to use about one quart of lime water to about twenty pounds of sugar, adding it to the syrup in the pan and mixing well.
The process of conversion can be combined with this refining method if desired by simply adding to the mixture the required quantity of fruit-acids, except when lime-water is used, in which case it is best to finish refining and carry on inversion by a separate operation. For the purpose of refining only, bring the mixture to a boil, but do not boil it longer than one or two minutes. Then filter and clarify. Coloration of sugar proves that it has been poorly refined, or that microscopic vegetations have been developed in it. Syrup made from such a product will have a bad taste and soon commence to ferment. Such sugar therefore should be rejected or carefully refined by this process, if necessary by repeating the operation of refining, or filtering the boiled syrup through an extra layer of fresh granulated animal charcoal arranged in a clarifying apparatus, as described later on Syrup-making Plants. - It is of great importance what kind of vessels are used, and whether they are heated by steam (jacketed kettles) or directly over the fire. Copper or brass vessels should be decidedly avoided, since we have frequently stated the injurious effects which those metals or metallic compositions have on the syrups. Copper or iron kettles, lined with pure block tin, are suitable, objectionable however, when fruit-acids are boiled or heated with the syrup. Kettles enameled without having any lead in their enamel are the most preferable, especially when acidified syrups are being prepared, as is the case when the inversion process is employed, or fruit syrups are prepared. (See "Lead Test" for enamel on page 348). Silver-lined kettles are the best, but very expensive, and therefore the enameled ones are preferred. Various devices or plants for syrup making by steam are recommended to the trade. We selected those that seem the most practical ones.
Fig. 412 is an English "Syrup-making plant," and constructed on cleanly and labor-saving principles. The tanks are jacketed, enameled, and of any convenient capacity. The syrup is filtered through felt bags; the pipes, taps and connections are of non-injurious material. This syruping-apparatus is generally fixed in a room above that occupied by the bottling machines, or on a raised platform. The elevated kettle is used to boil the sugar, which then runs as a syrup into the cast-iron enameled pans. The necessary essences, acids, coloring and flavoring matters are added after the syrup has become cool; it then passes through the felt filtering bags, which filter and clarify the syrup. From these the syrup passes into the slate cistern in compartments.
Fig. 412. - Syrup Making Arrangement.
The plan represented by this illustration (Fig. 413) is already referred to under Filtration of Syrups in Chapter XXVI (Filtration And Clarification Of Extracts, Essences, Etc)., page 46G, where a sectional view of the filter is appended. It combines the protected syrup filter with the syrup kettle and the syrup receptacle, both of which are covered, thus excluding air and accidental impurities, which is advantageous.
Fig. 413. - Syrup Boiler and Filter.
Fig. 414. - Syrup Mixer and Filter.
Another English plant is represented by Fig. 414.
The steam coil for heating the water, connected with a heating tank, as illustrated in Fig. 10, should if possible be placed outside the syrup room, so that the boiling water is run into the room by a tin pipe, instead of having live steam continually in the laboratory. The dead steam that arises from the cooling and mixing pans will not rise sufficiently to hurt anything. These arrangements can be increased side by side according to the extent of business.
A steam-jacket kettle with safety valve, a typical arrangement of the United States, and conveniently used and connected with any filtering arrangements, is here represented. It is a copper-kettle, tinned inside or enameled if desired.
Fig. 415.-Steam-Jacket Syrup Kettle.
Where steam is not available, an arrangement as shown in Fig. 416 will be of good service. It consists of a stove, for coal or wood firing, with sufficient accommodation to place a properly sized porcelain-lined kettle into it. More care must be taken during these manipulations' to prevent empyreuma, that is, burning of the sugar at the bottom of the vessel. Frequent stirring will prevent it. For all smaller services a suitable kettle, put on an ordinary stove, when those precautions are taken, may answer.
Fig. 416. - Bottler's Stove.