Excellent, reader Mark! Thank you. We’ve been talking a lot about gluten lately, your question is a continuation of that important topic. As we know, moisture and agitation causes gluten to develop. Developed gluten in a cake-like device is a problem because it toughens the finished product. Most of us have probably tasted over-beaten tea breads, those sweet but rubbery slices that sometimes appear on holiday buffet tables.
You can judge an over-beaten tea cake (or cake, or muffin) by sight: that very tall crown — a muffin with a conical top, a cake layer that’s humped up in the middle, a tea bread loaf that looks like a treasure chest. All evidence that the crumb is holding too much gas and steam. Believe it or not, while we bakers rely on chemical leaveners to create gas pockets that will fill up with steam in the oven, we ultimately want most of that gas and steam to escape.
A stretchy, glutinous batter will catch and hold most of it. That’s what creates the extra volume. A slice of over-mixed tea bread is suffused with lots of big or long holes which are also known as tunnels in “the business.” They’re another visual cue that tells you to leave Aunt Maddie’s slices of cranberry bread where they are and have another helping of mashed potatoes instead.