After passing the degree of " feather," sugar is inclined to " grain " or "candy," and will form a powder if agitated or stirred; for as the boiling is continued, the water evaporates until none is left to hold the sugar in solution; therefore the latter returns to the state it was in before the solvent was added. The water, being evaporated by boiling from the last degree, leaves a thin crust of crystals round the sides of the pan, which shows it has attained the candy height; this crust must be carefully removed, as it forms, with a damp cloth or sponge, or the whole mass will candy if suffered to remain.
The "ball" degree can be ascertained in the following manner. Provide a jug of clean cold water, and the stem of a clean tobacco pipe or a piece of round stick. First dip it in the water, then in the sugar, and again in the water as speedily as possible; take off the sugar which has adhered, and roll it into a ball between the finger and thumb in the water. If it forms a large ball which will bite hard and adhere to the teeth, it is termed "large ball."
For "crack," follow the directions given for " ball." Slip the sugar off the pipe or stick, still holding it in the water, then press it between the finger and thumb: it breaks short and crisp, with a slight noise.
To obtain " caramel" requires care and attention, and frequent trial. Try as before, and let the water be quite cold. On taking it off the pipe, it snaps like glass, with a loud noise; it will also assume a beautiful yellow colour; after this it will speedily burn, taking all hues from brown to black. To prevent burning, dip the bottom of the pan into a pail of cold water as soon as it comes to caramel; also be careful that the flame of the fire does not ascend the sides of the pan.
When boiling sugar, keep the top of the pan partially covered from the time boiling commences until attaining the ball or crack; the steam which rises, being thrown to the sides, prevents the formation of crust or crystals. To prevent graining, add a little acid when at the crack - a tablespoonful of common vinegar, 4 or 5 drops of lemon-juice, or 2 or 3 drops of pyroligneous acid: this is termed " greasing"; too much acid will grain it, and prevent boiling to caramel. A little butter added when it commences boiling will keep it from rising over the pan, and prevent graining. About as much cream of tartar as may be laid on a sixpence, added to 7 lb. of sugar with the water, or equal quantities of cream of tarter and powdered alum, added at the boiling stage, will also stop candying. Sugar is very liable to grain if poured on a hot slab, as may easily happen after several casts have been worked off. When sugar has been boiled or warmed several times, it is very apt to " run " and become sticky in a damp atmosphere. Acids in excess have the same effect.
If a panful should pass the degree intended to be boiled at, add a little water and boil again.
Every intelligent confectioner now uses a thermometer to guide him in boiling his sugar, the most common form in this country being Fahrenheit's. The temperature for "syrup" ranges* from 215° to 230° F. (102° to 110° C.); " blow " and " feather " mark about 235° F.. (113° C); "ball" reaches 240° F. (115 1/2° C); "crack" requires about 252° F. (122° C); and "caramel" follows at 260° F. (127° C).