Butter is essentially the fat of milk. It is essentially a water-in-oil emulsion and is usually made from sweet cream and is salted. Saltless (sweet) butter is also available in the market. Butter can also be made from acidulated or bacteriologically soured cream. Commercial butter can be produced from both sweets as well as cultured cream. Extraordinarily little cultured butter is produced in India and the U.S.A., although in Europe and Canada, cultured butter is an important product. However, most creamery prefers to produce butter from sweet cream as it results in sweet buttermilk with better economic value than sour buttermilk that results when sour/cultured cream is churned.
Composition of Butter:
- Reception of the milk-As the milk arrives, a sample is sent to the lab for initial analysis (fat, SNF, etc.); if it fits the standards, it is sent to the storing silos.
- Separation: Milk is transferred to the separator, where it is separated into cream and skim milk. The skim milk from the separator is pasteurized and cooled before being pumped to storage. It is usually concentrated and dried.
- Pasteurization: It is usually done at 82-88°C or more. (The high temperature is needed to destroy enzymes and micro-organisms that would impair the butter’s keeping quality).
- Ripening: Sometimes, cultures are added to ferment milk sugars to lactic acid and acquire desirable flavour and aroma characteristics for cultured butter. This is more common in European butter. Thus, ripening is the fermentation of cream with the help of a desirable starter culture, which helps develop flavour. The cream is ripened in 2 stages: 1st stage at 21°C to pH 5.5 and then 2nd stage at 13°C to pH 4.6. This step can be eliminated if sweet-cream butter is desired. So, Once the cream is pasteurized, it is transferred to the cream storage tank for ripening.
- Ageing and crystallizing: The cream is now transferred to the ageing tank and subjected to a controlled cooling program that gives the fat the required crystalline structure. The process is done for around 8 hrs at 14°C.
- Churning: The aged cream is now sent to the churner. In the churning process, the cream is violently agitated for 30 min at 6-14° C to break down the fat globules, causing the fat to coagulate and form butter grains and buttermilk.
Diagram of a churner
- Draining & washing: It used to be common practice to wash the butter after churning to remove any residual buttermilk and milk.
- Salting: After washing the butter granules, they are transferred to the blending tank and mixed with Salt.
- Packing & storage: The butter is finally patted into shape and then wrapped in waxed paper, and then stored in a cool place. As it cools, the butterfat crystallizes, and the butter becomes firm.
Note: Neutralization of cream
- Churning of High acid cream may cause high-fat loss, which can be prevented by neutralization. Thus, the objectives of neutralization are to reduce the acidity in cream to a point (0.14 -0.16%) which permits pasteurization without risk of curdling, to produce butter that keeps well in cold storage
Diagrammatic Representation of processing of butter in a continuous flow
Difference between Butter, Table Butter, and White butter.
Traditionally, butter is a product derived from cream, inverted to a water-in-oil emulsion (W/O) with a minimum of 80% fat. The butter’s continuous fat phase is a complex matrix of liquid butter oil and fat crystals, forming a network that entraps the water droplets and, to a limited extent, small air bubbles. Initially, the milk is concentrated to cream followed by a pasteurization process. Subsequently, the cream follows a temperature treatment where crystallization takes place. The churning process involves phase inversion of the crystallized cream to butter granules and buttermilk. The butter granules are plasticized by the kneading and mixing process to form the butter. To improve the butter quality, the system is equipped with a vacuum suction/Deaerator in which the incorporated air is removed. Removal of air from the butter will improve the butter’s texture and increase the shelf life due to less oxidation and the risk of free moisture.