The quality of dairy products obtained from their own livestock is important for farmers who receive them for sale. Therefore, the question of how to determine the fat content of cow's milk at home is very relevant. It is easier for livestock breeders keeping large herds to invest in a special apparatus for determining fat content. Housewives raising only a few cows can use simple measurement methods at hand.
What is the fat content of cow's milk?
The volume of fat contained in milk is most often measured on a relative scale, that is, as a percentage of the total mass of the product.For example, an indicator of 3.2% means that the fat in 100 grams of milk is 3.2 grams. In mass production, the concept of total fat content (in weight units) is used.
Fresh milk is the leader in fat content if stored at a temperature no higher than +7 OWith and no longer than a few hours, after which the fats are broken down into other compounds. The fattest milk is considered to be from Kholmogory, Kostroma and Sychevsk cattle breeds – the percentage of fat in it ranges from 3.2% to 4.5%, and in Yaroslavl cows it is almost 6.0%.
The following factors can affect the fat content of milk:
- breed of cow;
- features of the content - fattier milk from cattle, which spend most of their time on free grazing;
- feeding ration;
- age – milk reaches its maximum fat content in cows at 5-6 calvings.
In the summer, cows eat more fresh grass and drink large amounts of liquid. Therefore, in winter, milk becomes much fatter. Average fat content of cow's milk is 3.2-4.5%.
Measuring instruments
To check the fat content of milk immediately after milking, farmers with large herds of cattle often purchase a special device - a butyrometer. Such devices are indispensable on large livestock farms that trade in milk. The product in which it is necessary to find out the percentage of fat content should not contain impurities and additives, peroxide and starch, which prolong the shelf life of milk.
Using a butyrometer, you can determine the fat level from 0 to 6%. The device looks like an oblong tube consisting of a narrow and wide part. Once the milk sample is placed in the device, it will need to be heated and separated to separate the components of the product.
How to use the butyrometer:
- milk is poured into the tube;
- a component required for determining fat content is added - concentrated sulfuric acid. Thanks to the substance, a reaction begins that separates the product into fat and whey parts. At the border of contact between the two environments, a clear boundary is formed;
- isoamyl alcohol is poured in.
The butyrometer must be closed so that during the measurement procedure milk does not leak out of it, stain the laboratory surfaces and personnel clothing, and the loss of the product does not affect the results of the study.
The device is placed in a water bath, which is purchased complete with the butyrometer, and heated to 65-70 OWITH.
It is important to control the heating temperature using a thermometer so as not to spoil the product or get a false result. Afterwards, the butyrometer is placed in a centrifuge, where, as a result of exposure to milk at 1000 revolutions per minute, it is separated into fat and whey. The result (percentage of fat content) is determined using a butyrometer scale.
Determining fat content at home
To find out the fat content of milk yourself, you need to prepare a fresh sample of the product and a clean glass, the walls of which are strictly vertical. A mark is made with a marker at a height of 10 centimeters from the bottom of the dish. Milk must be poured into the glass up to the drawn line. If it has time to settle, it needs to be shaken.
The container with milk should be left for 6-8 hours, and then evaluate the result. The cream will be at the very top, and the thinner product will be located at the bottom. The thickness of the creamy layer is measured with a regular ruler - from the top of the liquid to the border with the lower (liquid) milk.
A more complex measurement method requires accurate scales. On the outer surface of the container, in which the settled product has been sitting for several hours in a row, the border of cream and milk is marked. Afterwards, the liquid can be poured into another container. Using a scale, the mass of water is determined, which is then filled with a milk can, to the bottom mark and the volume of water between the marker stripes. To do this, the container (can) itself is initially weighed, then the liquid located between the marks is poured and weighed, and then the rest.
Next, simple calculations are carried out: the weight of the liquid obtained between the marker lines must be divided by the total mass of water. The resulting figure must be multiplied by 100% - this will be the fat content of the milk cream. Then you need to measure the fat content of the milk. If the fat content of the cream is, for example, 15%, the coefficient will be equal to 0.25. In the case where the volume of the creamy mass is 1% or 2% greater, add 0.01 or 0.02 to the coefficient, respectively. If the mass of cream is less, you need to subtract it from the coefficient.
This can be determined using an example: it turned out that 300 grams of milk accounted for 48 grams of cream. You need to calculate the percentage of cream: 48/300*100%=16. The coefficient of standard creamy fat content is 0.25 (at 15%), add 0.01 to it, you get 0.26. Then you need to calculate the concentration of the milk: 16% * 0.26 = 4.16%.
What can affect the final fat content?
It is important to consider that the percentage of dairy products can be increased under several conditions:
- the thinnest are the first streams of milk milked from the udder. They contain only 1% fat;
- The last (hind) milk is the thickest;
- fatter and thicker milk in cows fed with balanced feed during the dry period - if the farmer prepares feed for cattle enriched with vitamins, minerals, proteins, fats and carbohydrates.
Depending on the breed, the milk will also have more or less fat. Typically, cows that produce less milk will have more concentrated milk and vice versa.
Throughout the summer, cows are grazed on pastures, so the milk acquires not only natural concentration, but also positive taste qualities, as well as a pleasant creamy shade. In winter, to maintain fat content at the proper level, cattle must be fed a balanced diet - hay, grass meal, silage, vegetables, porridge with boiled root vegetables and vegetables.
