Reader Joe from Israel asks:
I’ve seen the terms “tender crumb” and “open crumb” and I think I know what they mean. Can you define it for us? What affects the crumb of the cake: processing methods, ingredients or both?
Thanks Joe! “Crumb” is simply the word for the interior of a bread, cake or pastry — the stuff that’s contained within the crust. Like a crust, a crumb can take all different forms. It can be soft and airy, firm and dense, tough, tender, you name it. Bread makers use the words “open” and “closed” (or “tight”) to describe bubble sizes in a finished bread. An open crumb has a few really big holes (think European peasant bread), a tight crumb has lots and lots of tiny holes (think sandwich bread).
Lots of things can affect the look and texture of cake crumb: the type of flour, the proportion of fat, egg, sugar and such. However handling plays a big roll as well. That’s why choosing the right mixing method is so important. Improper or overly aggressive mixing can result in too much activated gluten (protein), which can give you a rubbery, tough crumb. Too little mixing can create a crumb that won’t rise well because there isn’t enough activated gluten, and all the gas and steam escapes.
This is an extremely broad topic, so forgive me if I’m not discussing it especially well. What I will say is that the perfect crumb is really in the eye of the beholder — or baker. These days, in the realm of layer cakes, very rich, moist and tender crumbs are preferred. I like a tender crumb in a cake, but it’s an aesthetic that can be pushed too far. Sometimes a crumb that’s a little drier or a little tougher can be a good thing. A ultra moist and tender batter intended for a layer cake can be a disaster when used for, say, a cupcake, which needs to be firm enough that it can be picked up without falling apart.