Milk straight from the cow separates naturally, with the high-fat cream rising to the top and the denser milk settling beneath, creating a division called the cream line. Customers liked glass bottles so that they could see the cream line and judge the quantity of cream. Ingenious gadgets were invented to solve the problem of how to skim pure cream off the top of milk and how to whip cream quickly without strain or mess.

Before pouring non-homogenized milk from the bottle, people had to hold the cap and shake the bottle to mix in the cream evenly. In 1899, August Gaulin applied homogenization to milk.He patented a process that broke the fat globules into smaller units, which remained in suspension, not separating. Homogenized bottles of milk, the same consistency all the way through, required no shaking and had no cream line.Milk homogenization was first used commercially to keep ice cream ingredients uniformly and smoothly mixed.