Classic Culinary Arts:

How To Boil Sugar

The degrees of boiling sugar are variously divided by different cooks. Some give six and others as high as eight. The Stench boil sugar for nearly all their desserts. For all practical purposes a cook need understand only three stages. Put one cupful of granulated or loaf sugar and half a cupful of water on to boil. When the mixture has boiled fifteen minutes, dip the fore-finger and thumb in cold water and take up a little of the syrup between them. If, upon drawing them apart, the syrup forms a thread, it is at the second degree. This is the best stage for frozen fruits, sherbets, and preserves.

If, a little later, when some syrup is taken up with a spoon and blown hard, it flies off in tiny bubbles, it is at the fourth degree, called the souffle. It takes about twenty minutes' boiling for this. The syrup is then used for biscuit glace and various kinds of creams. At this stage it also gives sherbets and fruits a much richer flavor than when used at the second degree.

If, when a little syrup is taken up on the point of a stick or skewer, and dipped in cold water, it breaks off brittle, the sixth degree has been reached. This is the stage where it is used for icing fruit and cake, the dish being called fruit glace or gateau glace. The syrup must never be stirred, as this will cause it to grain. Great care must be taken that it does not boil after coming to the sixth degree, as it burns quickly after that point is reached.