Fudge Sauce
1 cup sugar 1 cup Karo, Red Label 1/4 cup water 11/2 squares chocolate cut in bits 2 drops vanilla Few grains salt 1 tablespoon Mazola Combine the ingredients, bring to boiling point and boil until the mixture forms a short thread. Add the vanilla, stir until it begins to thicken and serve hot.
A straightforward corn-syrup fudge sauce from a manufacturer's booklet, written when Karo and Mazola were sold in labelled grades that no longer exist. Two things need translating: the syrup and the words "short thread."
- Karo, Red LabelKaro was sold in labelled grades that no longer exist, and accounts of which was which disagree: Blue Label is generally identified as the crystal-white syrup, while Red Label is variously described as the light amber (golden) grade and as the darker one. Ordinary light corn syrup is the safe substitution; dark corn syrup will work but will push the flavour toward molasses and mask the chocolate.
- MazolaMazola was and is corn oil. A tablespoon of any neutral oil serves the same purpose here, giving gloss and keeping the cooled sauce from setting hard. Butter is a common modern substitute and tastes better, though it will cloud the shine slightly.
- Squares of chocolateA "square" is one ounce of unsweetened baking chocolate, so 1 1/2 squares is 1 1/2 oz. Given the cup each of sugar and syrup, unsweetened is what is meant; semisweet chips will make the sauce cloying.
- Short threadThis is the thread stage, conventionally in the region of 223-235F on a candy thermometer, where syrup lifted on a spoon falls in a thread that breaks quickly rather than spinning out. The book gives no thermometer reading; err on the low side, as cooking further will give a stiffer, more fudge-like set.
- The hingeStir constantly while it comes to the boil so the chocolate melts into the syrup rather than scorching on the bottom, and take it off the heat the moment it threads. The final "stir until it begins to thicken" is meant to be brief; prolonged beating off the heat starts sugar crystallisation and turns the sauce grainy.
- VanillaTwo drops is a very small quantity by modern habit; up to about a quarter teaspoon of extract suits most palates, added off the heat as the recipe directs so it does not cook away.
- Yield and servingAbout 1 1/2 cups, enough for six to eight servings over ice cream, plain cake or steamed pudding. It thickens considerably as it cools; reheat gently over hot water with a spoonful of water or cream to loosen it.
Books of this kind were house publications of the Corn Products Refining Company, which owned both Karo syrup and Mazola oil, and the recipes are built to demonstrate them - hence a chocolate sauce that calls for corn syrup and corn oil. The chemistry behind the pitch was sound: corn syrup is largely glucose and dextrins, which interfere with sucrose crystallising, so a sauce made partly with it stays smooth and pourable instead of setting up grainy the way an all-sugar syrup can. "Fudge sauce" as a name follows the fudge craze that spread through American women's colleges around the turn of the twentieth century, and the thread test here is straight candy-making practice, borrowed from fudge itself and simply stopped short of the firmer ball stages.