Butter making process

Butter is a water in oil emulsion with a legal maximum water of 16% (butter can be flavoured butter, cultured butter, coloured butter (annato) and salted or unsalted butter.)

Butteroil or Anhydrous Milk Fat (AMF)-

AMF is 99.9% Pure Butterfat usually produced by heating, vacuum to remove odours and centrifugation. AMF can be produced directly from cream or it can be produced from butter.

Ghee

Ghee is similar to AMF but not quite as refined - usually produced using a simple boiling and decanting process.

Buttermaking expert and butter making equipment-

Butter is made from milkfat (cream) usually separated from the milk to 40% fat and then aged overnight (approx 12 hrs) in a controlled temperature and gently agitated tank (Ageing tank) at approximately 8C to 12C.

The cream ageing process for buttermaking allows the fat to partially crystallise.During the crystallisation process a chemical reaction takes place and heat is released causing a temperature rise in the cream (Latent heat of Crystallisation) hence the necessity for gentle agitation and controlled temperature. The slightly elevated temperature during ageing together with gentle agitation allows the fats to move in the emulsion and to crystallise together giving larger fat globules which will break more easily during the Butter churning process. If the cream is too cold then the fats will not move and crystallise as easily as they will be too viscous. Without gentle agitation then the fats close to the tank edge will cool more than the fats in the centre of the tank giving an uneven crystallisation. The quality and gentle handling of the cream is critical to ease of manufacture of butter and also the yield of butter achieved. If the butter or cream is over pumped then this can damage the fat globule membrane (lecithin layer) releasing free fatty acids which will be lost to the buttermilk.

The better the control of the cream fat % and the temperature of cream fat crystallization, the more consistent the butter should be, so for volume manufacturing with continuous buttermaking, attention to detail is critical to ensure optimised yields.

A 1% variation in moisture and salt content due to processing variation can be very costly to manufacturers as the legal imit of 16% can not be exceeded so the moisture loss is a physical loss of profit / yield.

Continuous buttermakers ideally would have a cream tempering section which would preheat or precool the cream to a consistent controlled temperature to feed to the continuous buttermaker to ensure process consistenty.

The cream feed rate to the continuous buttermaker should also be controllable.

The continuous buttermaker would ideally have cooling on the barrel and also a facility to recycle back to the tank in the event of a stoppage or breakdown.

Salt is generally dosed in a water / slurry form into the working section of the buttermaker.

Buttermilk can be partially recycled to the working section when required but generally it is passed theough a sieve to recover fines and grains and separated, pasteurized or simply spray dried and sold as buttermilk powder.

Some manufacturers will add back a small quantity of buttermilk (5%), pasteurized back to the raw milk silos where it is then reprocessed in the usual way with the raw milk and this can reduce wastage / losses but care needs to be taken that this does not contravene any finished product specifications.

The butter exiting from the barrel can go direct to a packing machine or into a buffer tank prior to the packing machine.

Bulk butter is generally filled into a coloured polythene liner directly into a cardboard box (bulk 25kg) after which it is sealed, coded and dated and put either into chilled storage or more frequently into frozen storage with sample boxes kept until the next day for butter grading.

Butter grading is carried out for a number of parameters; free moisture, greasiness, salt, taste and appearance basis ensuring a smooth finish (butter grading is quite specialist and we can instruct you on how to do this as it requires demonstration)

Once laboratory results on yeasts and moulds, coliforms, moisture and salt etc. are available these are matched with the grading results and the is butter released, as appropriate.

The shelf life on chilled butter is generally about six weeks but butter can be frozen for a year and then packed for retail sale with a six week chilled shelf life.

One of the biggest risks to manufacturers is Yeast and moulds and coliforms so attention to detail is required in manufacturing controls. Yeasts and moulds are ubiquitous in the atmosphere and for high volume manufacturers it will be critical to have clean filtered overpressure air in the buttermaking and packing rooms

In the EU cream would generally be pasteurised at about 80c, but in developing countries it is sometimes higher due to higher levels of contamination. Bulk butter is generally stored frozen at below -18C for up to 12 months prior to defrosting / tempering to a suitable temperature for packing. The shelf life of the retail packed chilled butter will generally commence from the packing date and not from the produiction date. The chilled shelf life of butter will usually be up to six weeks. Cleanliness of the outer wrapper / packaging is also critical to shelf life as any grease on the outer wrapper will result in yeasts and mould growth resulting in the potential for contamination of nearby products.

Butter variants-

• Unsalted sweet cream butter
• Salted butter (usually 2 to 4% added salt)
• Acidified or cultured cream butter
• Flavoured butter
• Butteroil

Butter Processing: An Insight

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.

Process:

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.

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.

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.

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.