This section is from the book "The Steward's Handbook And Guide To Party Catering", by Jessup Whitehead. Also available from Amazon: Larousse Gastronomique.
In cooking such sweet preparations as are made with milk or cream, whether for custards, puddings, sauces, or whatever else, the sugar should be mixed in before the milk goes on the fire, and it will prevent burning on the bottom. This simple precaution does away in many instances with, the necessity of following the onerous course demanded by most cook-book writers, to "stir the mixture (of eggs, milk, flour, etc.,) constantly till it boils." The milk and sugar together take care of themselves, and when poured to the eggs, starch, or steeped tapioca the cooking is almost finished and little time lost.
These are the smooth, the thread, the blow or feather, the ball, the crack, the caramel. 1st.-Smooth, or 215 degrees by thermometer; as an example take 13 lbs. of loaf sugar, to which put 3 pts water; as soon as it boils see that all the sugar is dissolved, if not use the spaddle to assist in doing so, let it boil for five minutes or so, dip into it the handle of a teaspoon, draw it between the finger and thumb; if on working them together they feel slippery, that is the first degree of smooth; this degree can be used for crystallizing liqueurs and various other goods. 2d-Thread, or 230 degrees by thermometer. In the course of a few minutes the sugar passes into this degree; having soaked the previous sugar off the spoon, try the boil again, close your finger and thumb together and gently part them, when, if you perceive a threadlike appearance between them, it has passed into this degree, which can now be used for making liqueurs or bonbons, etc, 3rd - Blow, and feather, 240 degrees. In two or three minutes from the last sugar passes into this degree; dip a small skimmer or slice with holes in it into the sugar, drain it off quickly and blow hard through them, you will perceive bladders and feathery particles pass away.
This is the blow or feather, very useful degrees, and can be used for candying- peel, fruit, etc. 4th - The ball, or 250 to 255 degrees. About the same time as • the last this degree arrives, have some cold water handy. Take a little sugar out of the pan with the handle of the spoon, dip it into the water, and if it is tough and you can work it about with the finger and thumb like a pinch of hot bread, that is the ball which can be used for candies or creams, if jams or preserves are to be mixed in after being worked into cream by the spaddle. 5th - Crack, 310 to 315 degrees. Use the same process in testing as the last, but quickly; take a little out of the pan, put it into cold water, when it will crack, or slip it off quickly and bite it well; if it crunches and leaves the teeth without sticking to them, pour the sugar out instantly on your slab. This is the most usesul degree to the hard confectioner for all purposes of boiled sugars. (N.B. - In trying this last degree, unless an experienced workman, the pan must be lifted off the fire.) 6th - Caramel. It is not necessary to try this degree in the same way as the last; the instant the sugar changes color, which must be closely watched, as it occurs rapidly, it must be poured out, or if not raquired on the slab but for other purposes, such as spinning sugar, etc, place it in a tub of cold water the size of the bottom of the pan, to stop the heat, or it will turn very dark.
This degree is mostly used for spinning sugar for ornamental table use.
As a rule, put about a quarter of an ounce of the cream of tartar to an eight or ten pound boil, accordiag to the strength of sugar; a teaspoonf ul of the strong acids, or tablespoonful of lemon juice or the best malt vinegar to the same quantity of loaf sugar to reduce its strength. The same effect is produced by using "glucose," a fifth part of which to any quantity of sugur will reduce it to the required working condi -tion. The advantage of this is in increasing the bulk at a small cost. Although, strictly speaking, this is an adulteration, it is quite wholesome.
Are made of copper, degrees properly marked for the purpose, the scale beginning at 30, the degree for simple syrup as used in making mousses (ice creams) being 32. Can be purchased at confectioners' supply stores.