Working

Once churning generates the desired size of butter grains, often the size of a wheat seed, the water phase of the cream is drained off. This is the original buttermilk, rich in free globule membrane material and with about 0.5% fat. The solid butter grains may be washed with cold water to remove the buttermilk on their surfaces. The grains are then “worked,” or kneaded together to consolidate the semisolid fat phase and to break up the embedded pockets of buttermilk (or water) into droplets around 10 micrometers in diameter, or about the size of a large fat globule. Cows that get little fresh pasturage and its orange carotene pigments produce pale milk fat; the butter maker can compensate for this by adding a dye such as annatto or pure carotene during the working. If the butter is to be salted, either fine granular salt or a strong brine goes in at this stage as well. The butter is then stored, blended, or immediately shaped and packaged.