Instinctively, I reached for a pound of butter at the store today. It was only then that I realized how many bricks of butter went through my kitchen in in November/December this year. Butter in Thanksgiving breads, gravies, and sautéed with veggies, butter brushed on baked rolls and buns during holiday break, butter in Christmas goodies for friends and neighbors… So. Much. Butter.
Butter makes for an interesting food science topic, and it’s one kitchen staple not easily replaced. Few products bring butter’s characteristic rich, delectable mouthfeel to food while achieving the same functionality in recipes.
So…the science behind butter?
Butter is made from cream. Mechanical energy like churning, or other agitation, is applied to cream to create butter by reversing its natural emulsion from a water-in-oil emulsion to oil-in-water emulsion. (More on emulsions here.) The churning process causes the fat globules in cream to collide and mass together. These butter masses grow larger under agitation until finally the butter mass separates from a small amount of remaining liquid, a low-fat byproduct called buttermilk. The butter mass is separated and washed, and the buttermilk drained from the tank. After production, butter is packaged and sent to retailers and consumers.
The ingredient declaration on a butter wrapper is a short one. Often, salt can be added to the butter to act both as a preservative, and flavor enhancer. (The salt dissolves into the small percentage of water which remains in the butter.)