Continuing with John Nott, here are his entries on crack’d, feather'd, and pearl’d sugars.
168. To boil Sugar to its crack’d Quality.
To know when the Sugar has attain’d to this Degree, you must provide a Pot or Pan with some cold Water: Dip the tip of your Finger into it, then dip it quick into the boiling Sugar, and then immediately into the cold Water; and keeping your Finger in the Water, rub off the Sugar with the other two Fingers; and if it breaks afterwards, making a kind of crackling Noise, it has attain’d the crack’d Quality. [Section SU; 1726 edition.]
169. To boil Sugar to its feather’d Quality.
When after some other Boilings, you blow through the Skimmer, or shake the Spatula with a backstroke till thicker and larger Bubbles rise up on high, then the Sugar has attain’d its feather’d Quality; and when, after several Trials, you perceive the Bubbles thicker, and in greater Quantity, so that several of them stick together, and form, as it were, a flying Flake, then the Sugar is greatly feather’d. [Section SU; 1726 edition.]
170. To boil Sugar to its pearl’d Quality.
Having boil’d your Sugar to its smooth’d Quality, continue the Boiling a little longer, and then try a Drop of it between your Finger and Thumb, as before, and if the String continues sticking to both, the Sugar is arriv’d at its pearl’d Quality; the greater pearl’d Boiling is when the String remains, though the Finger and Thumb be quite stretch’d as far as you can extend them asunder; this Degree of Boiling may also be known by a sort of round Pearls that rise on the Top of the Sugar. [Section SU; 1726 edition.]
Nott, John. Cooks and Confectioners Dictionary. 1726. Facsimile. Edited with introduction and glossary by Elizabeth David. London: Lawrence Rivington, 1980. [Limited numbered edition.]