Butter from cream
Cream is 30 to 40 percent fat, in globules wrapped in thin membranes. Whipping or shaking breaks the membranes, and the fat sticks into clumps. Past whipped cream, the clumps join and the water drains off as buttermilk.
Rinse and press the butter
Butter traps buttermilk in tiny pockets, and leftover buttermilk spoils faster than fat. Knead the lump under cold water, pouring off the cloudy water until it runs clear, then salt it if you like. Finished butter is about 80 percent fat.
Test yourself
Questions from the interactive lesson, with the answer and the why.
You shake a jar of cream until it thickens, then thin liquid sloshes around a solid lump. What happened?
Fat clumped and buttermilk split off. The membranes broke, fat joined up and the water was squeezed out.
True or false: The watery liquid left after churning butter is traditional buttermilk.
True. The thin liquid left after churning is traditional buttermilk.
What went wrong? You stop mixing at stiff whipped cream and wonder why there's no butter.
You stopped before the fat clumps broke free. Keep mixing past whipped cream until grains form and buttermilk separates.
Fill the blank: Fat clumps together in churning once the ___ around the globules break.
Fat clumps together in churning once the membranes around the globules break. Breaking the membranes lets the fat stick together.
Which dairy gives the most butter per cup?
Heavy cream, at about 35 percent fat. High fat means more clumps and more butter per cup.
Roughly what percent of finished butter is fat?
About 80 %. Butter is about 80 percent fat and roughly 16 percent water.