How do we obtain our butter? First the milk processor pasteurizes, then ages the cream

for at least 8 hours and finally churns it into butter by physical agitation. Aging the cream allows

the milk fat to crystallize and weakens the fat globules. The forceful agitation of churning breaks

each tiny globule’s delicate membrane and allows the globules to clump together into a solid,

that we call butter. The churning action expels a byproduct liquid, that the industry calls

buttermilk. This is not the kind of buttermilk we drink, it only has the same name.

TASTINGS Butter as an emulsion

Two types of emulsion are common in the kitchen—oil- in-water, as in salad

dressing, and cream-and-water-in-oil, as in butter. Churning the cream changes

the emulsion from one form into the other. Butter’s starting material, heavy cream

is an emulsion of oil-in-water. After churning it becomes an emulsion of cream-

and-water-in-oil—just a physical change.

After the cream becomes butter, it goes through washing and then a mechanical

manipulation (something like kneading bread dough) to reduce the size of the fat crystals. This

makes it softer and more spreadable. Butter oxidizes (turns rancid) at room temperature

relatively fast. Chilling slows down the oxidizing process. Antioxidants would help reduce

rancidity, but U.S. law restricts adding anything but salt and a coloring agent to butter. Salt

extends its shelflife, coloring enhances its appearance.

TASTINGS From cream to butter

One gallon (3.8 l) of cream containing 40 percent fat produces 4 pounds (1800 g)

of butter and a little over 2 quarts (1 l) of buttermilk-like liquid. They don’t waste

the leftover liquid. The dairies condense it down to 25 percent into a syrupy liquid

which they use in other dairy products to enhance flavor and add richness, for

instance, in ice cream.

Salting butter is a habit left over from the days before refrigerators. By the time

refrigeration was common, people were used to the flavor of salted butter, and processors

encouraged its use because it extended the shelflife. The amount of salt they use in butter is 1.5

to 1.8 percent (about 1¾ teaspoons in a pound or 450 g). The most common coloring agent is

annatto, a natural reddish-yellow dye. Without coloring, most butter is too white to look like the

real thing. The natural color depends on what the cows, who produce the cream, eat so in some

seasons they must use coloring to boost the yellowness—or consumers start complaining.

What Butter is Made of:

Substance

Fat

Water

Milk solids

Salt (if salted)

Weight in %

80-84%

15-16%

1.5-1.8%

That 15 to 16 percent water you see in the table is the reason butter sizzles when you heat

it in the sauté pan. The water boils in the hot pan, turns into steam and tries to escape from its

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