Blueberry muffins: with a tender, white cake crumb.
These muffins are beautiful and taste amazing. I originally baked these muffins a couple of weeks ago on a whim. Delicious! The only downside, I did not use paper liners as recommended in the recipe. I used a knife to loosen each muffin but even with further prodding they were hard to remove. By the time I flipped them onto the cooling rack they began to sag. Too many big fresh blueberries and the integrity of the crust had been damaged so they did not hold their shape. This time I used parchment wrappers. What a difference. To be honest, I was also less exuberant with the berries. The fresh, late season berries I used this time were smaller but I still used restraint.
What makes these muffins special is their lovely white color AND the scrumptious cake surrounding the plump berries.
The fat and lactic acid from sour cream contribute to the tenderness of the muffin.
Sour cream contains fat and is made from culturing cream. It is always the fat, isn’t it? The cultures act as emulsifiers (the molecular structure holding the fat and water together). Lactic acid (gives sour cream its tang) causes the proteins in the sour cream to coagulate to a gelled consistency. Buttermilk comes from milk (surprise!) and has a higher pH than sour cream. So for many baked goods they are not interchangeable without changing the outcome.
Baked goods that contain cultured dairy products, such as sour cream, also usually contain baking soda. Acid from the sour cream reacts with baking soda and carbon dioxide gas is produced. This can be a significant source of leavening for these baked goods. If there is excess acid from the sour cream then the pH of the batter will lower resulting in increased tenderness and in some instances a whitening of the baked product. Aha!
The addition of sour cream certainly enhances the flavor of these muffins but the sour cream also plays an important role in the baking chemistry.