Yield of Cream

The yield of cream from milk can be calculated by the formula given below:

Quantity of cream =(Fat per cent in milk - Fat per cent in skim milk)/(Fat per cent in cream - Fat per cent in skim milk) X Quantity of milk

In a dairy plant for practical purpose approximate yield of cream can also be calculated in the following manner:

i) Calculate the total quantity of fat in milk.

ii) Deduct the fat loss amounting to about 3% of total fat, which is lost in skim milk under standard operating conditions.

iii) The approximate yield of cream containing different fat percentage per kg of available fat is obtained by multiplying it by a multiplication factor given in Table below. However the multiplication factor for cream containing fat percentage other than that mentioned in the table has to be calculated separately.

Let,

Quantity of milk = M

Fat per cent in milk= fm

Total fat in milk = M fm /100 = F

Loss of fat at the rate of 3 % of total fat = 3 F / 100= 3 M fm / 10,000

Available fat = F 1= Total fat in milk – Fat in skim milk

= F - 3F / 100 =100 F – 3 F / 100

(100 F – 3 F)/100

= 97 F / 100 =0.97 x M x fm /100 = .0097 x M x f

Yield = Y = K x M x fm

Where,

M= quantity of milk

fm = Fat percent in milk

K = Constant=0 .0097

In order to estimate the yield of cream the total fat is multiplied by the multiplication factor as shown in Table depending on the fat content desired in cream.

Multiplication factor for calculating yield of cream

 If 4.0 kg milk fat is available from 100 litres of milk after loosing in skim milk (i.e.,3% of fat available in skim milk), then the yield of cream will be:

4 x 2.5 = 10.0 Kg (40% fat cream)
4 x 2.0 = 8.0 Kg (50% fat cream)
4 x 1.67 = 6.68 Kg (60 fat cream)
                                
Percent fat recovered in cream = (Kg fat in cream)/(Kg fat in milk) x 100
                                  
The yield of skim milk can be calculated by the following formula:

Quantity of skim milk =(Fat per cent in cream- Fat per cent in milk)/(Fat per cent in cream- Fat per cent in skim milk) X Quantity of milk
                                    
Per cent fat loss in skim milk =  (Kg fat in skim milk)/(Kg fat in milk)  x 100