• Why do I add cornstarch?
The addition of cornstarch (called cornflour in British recipes) helps give the taffy a smooth texture.

• Why do I add corn syrup?
Corn syrup acts as an "interfering agent" in this and many other candy recipes. It contains long chains of glucose molecules that tend to keep the sucrose molecules in the taffy syrup from crystallizing.

In this taffy recipe, the butter also acts as an "interfering agent"—the milk proteins in the butter interfere with crystal formation as well.

• What is glycerin?
Glycerin is a sweet, slippery, colorless liquid that's made from fats and oils and is most often a by-product of the soapmaking process. It's used in many soaps and cosmetic products, cake icing, as a lubricant, and to make nitroglycerin—an ingredient in dynamite! (Note: glycerin itself is not an explosive substance, so it’s safe to use in your kitchen!) In this taffy recipe, glycerin helps give the candy a soft, creamy consistency.

Glycerin can be found in many drugstores, as well as some supermarkets and craft stores in the baking supplies section, or in cake-decorating stores. Be sure to purchase food-grade glycerin.

• Why do I need to stop stirring after the syrup begins to boil?
At this point, you have dissolved the crystal structure of the sugar. Stirring or other agitation is one of the many factors that can encourage the fructose and glucose molecules in your syrup to rejoin and form sucrose—crystals of table sugar.

• Why do I wash down the sides of the pan?
The sugar crystals are dissolved at this point in the process. But a single seed crystal of sugar clinging to the side of the pan might fall in and encourage recrystallization.

• Why do I need to pull the taffy?
Pulling taffy aerates it, or incorporates many tiny air bubbles throughout the candy. This makes it lighter and chewier.

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