7.6 Thick and thin: viscosity

Chocolate that flows

Chocolate is sold in different viscosities, and a confectioner picks the one the job needs. The amount of cocoa butter is the main thing that sets how runny chocolate is. Emulsifiers such as lecithin also thin melted chocolate so it flows smoothly, and since lecithin costs less than cocoa butter, it can bring the price down.

Match the chocolate to the job:

• Thinner chocolate fills molds such as Easter eggs, because it runs easily into the shapes. It also suits a thin, attractive, protective coat on cookies and most cakes, and the dipping machines called enrobers.
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• Thicker chocolate suits ganache and flavoring creams and fillings.
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Viscosity differs from one maker to the next, and a single type of chocolate may come in more than one. Bakers sometimes change it themselves. A little vegetable oil thins chocolate used to coat squares, which makes them easier to cut later.

Chips and chunks are made to stand up to heat, so they keep their shape in cookies. Some fine chips hold as much as 65% chocolate liquor, yet above about 40% they tend to smear as they bake.

Making things thicker

Bakers thicken with two kinds of agent: starches and gums. Nearly all come from plants. Gelatin is the one exception. Starches all come from land plants, while some gums come from the sea.

Bakers thicken things for three reasons: so fillings are easier to work with and bake, to firm products so they can be served neatly, and to give a glossy skin that looks good and keeps the food from drying out.