I’ve always loved brown sugar but it wasn’t until I lived in Hong Kong that I realized its importance to my baking. In Canada I had always used the same brand of light brown sugar. In the grocery stores in Hong Kong, frequented by ex-pats from the UK and Australia, I found that there was a wide range of brown sugars available. Unfortunately none of them did justice to my family’s favorite chocolate chip cookies. I could never figure out why. Was it the butter or the brown sugar?
This morning while reading an old copy of a magazine, Summer Entertaining from the Editors of Cook’s Magazine, I found a small article written by Erika Bruce titled Science: Why Brown Sugar Makes Chewy Cookies. In the article the author discusses how substituting brown sugar for granulated sugar in a cookie recipe changed the texture. She goes on to discuss the extra moisture in brown sugar, which burns off in the oven rendering not much difference between the sugars. As it turns out, the difference is invert sugar which is not found in granulated sugar.
“How does invert sugar work its magic? Invert sugar consists of glucose and fructose, two simple sugars. Invert sugar is especially hygroscopic, meaning that it pulls water from wherever it can be found, the best source being the air. And invert sugar keeps drawing in moisture even after cookies have been baked, thus helping to keep them chewy as they cool. So when it comes to chew in cookies, regular granulated sugar – with its lack of invert sugar – is simply no competition for brown sugar.”
So there is something to the science of brown sugar as it affects our baking. Hope this helps you with your baking or at least helps explain why some recipes call for granulated and why others use brown sugar.