On Food and Cooking

butter with a fat content higher than the
standard 80%. France specifies a minimum fat
content of 82% for its butter, and some
American producers aim for 85%. These
butters contain 10–20% less water, which can
be an advantage when making flaky pastries
(p. 563).
Whipped butter is a modern form meant to
be more spreadable. Ordinary sweet butter is
softened and then injected with about a third
its volume of nitrogen gas (air would
encourage oxidation and rancidity). Both the
physical stress and the gas pockets weaken the
butter structure and make it easier to spread,
though it remains brittle at refrigerator
temperature.
Specialty butters are made in France for
professional bakers and pastry chefs. Beurre
cuisinier, beurre pâtissier, and beurre
concentré are almost pure butterfat, and are
made from ordinary butter by gently melting
it and centrifuging the fat off of the water and