What’s the deal with the corn starch?

A number of you have asked that in regard to the waffle recipe I put up. It’s a good question, especially since most of us have been trained to think of corn starch (flour) as a thickener versus a bread building material. But in fact corn flour does work well as a regular flour, and possesses special functional qualities that make it highly useful for producing feather-light cakes like waffles.

We all know how easily corn starch gelatinizes (disperses into a moisture-trapping lattice) when it’s ground to a fine powder, mixed with water and heated. It’s that very property that we count on when we employ it as a thickener. Wheat starch gelatinizes very well too, however it brings along a little extra baggage: protein (gluten). That protein, as well all know, creates elasticity in a dough or batter. That’s good because a stretchy dough captures gas bubbles and creates rise. However there gets to be a point with cakes and pastry where the stretchiness becomes counterproductive and begins to a.) constrain a rise, holding it in like a rubber band, and b.) make the finished cake tough. We solve the problem by cutting the flour with corn starch.

Commercial millers put a similar principle to work when they bleach cake flour as heavily as they do. The process “denatures” (messes up) the proteins that would otherwise inhibit some of the rise and/or create a chewy texture. In fact a rough cake flour equivalent can be created by substituting a few tablespoons of corn starch in every cup of flour that a cake recipe calls for. Conversely, should you not have corn starch around, the waffle recipe below also works very nicely using all cake flour.