Separation of fat or cream from milk

Most milk plants separate milk for standardization or the obtain cream for bottling purpose and skim milk for butter milk and cottage cheese.

A layer of cream will form on the top of fresh milk, as it comes from cow, if it is allowed to stand for twenty or thirty minutes. This known as gravity creaming and it was very important prior to the invention of the cream separator. For many years it was customary to heat milk to 85 to 95 °F separation, because at this temperature the difference in density between the fat and skim milk is greatest and results in the most efficient separation of fat from skim milk.

Cream is separated from milk in a cream separator. Cream separator is a heavy metal bowl spinning at a very high speed which sediments the skim milk phase of incoming milk toward the wall of the bowl and displaces the cream inward along the centre of the bowl.

The cream and skim milk can then be recombined in desired ratios to obtain low-fat, light and whole milk with 1%, 2% and 3.25% fat respectively. This standardization usually is performed in a continuous manner.
Separation of fat or cream from milk

Decreaming Process

Decreaming Process
During processing, milk fat is removed partially or completely in order to:

• Obtain a fat-reduced or fat free

• Concentrate milk fat or the production of high fat products

• Standardize the fat content of milk

Decreaming (separation, centrifugation) is the mechanical separation of milk into cream and skim milk by means of centrifugal forces.

The decreaming process has significant economic importance, as it controls the efficiency of the fat separation.

The key objective is to manufacture a skim milk with the lowest possible fat content, which corresponds to good decreaming efficiency. Knowledge of the basics of the fat separation is important for an optimal decreaming process.

Decreaming is based on the facts that fat exists in polydisperse system in an emulsified state and that the specific density difference between milkfat and skim milk is fairly large.

Basically two processes for fat separation are possible, natural decreaming and separation with machine. Natural creaming has no industrial significance.
Decreaming Process