Overrun in ice cream

Overrun is usually defined as the volume of ice cream obtained in excess of the volume of the mix. It is usually expressed as “percent overrun”. The increased volume is composed mainly of air incorporated during the freezing process. The amount of air which should be incorporated depends upon the composition of the mix and the way it is processed and is regulated so as to give that percent overrun which will give proper body, texture and palatability to the ice cream. Too much air will produce a snowy fluffy ice cream while too less air on the other hand will lead to soggy, heavy ice cream.

i) How to obtain and control overrun: The following factors need to be considered in determining the amount of overrun in ice cream.

•  Legal regulation enforced in the market area.
•  Total solids content of the ice cream mix.
•  Type of ice cream to be made (fruit/nut ice cream etc.)
•  Selling price of ice cream.
•  Type of packages.

 The overrun attainable at the freezer depends upon the following points:

•  Type of ingredients used in the mix.
•  Sharpness of scrapper blades.
•  Speed of dasher.
•  Volume of refrigerant passing over freezing chamber.
•  Temperature of refrigerant

 The use of proper overrun tester will ensure uniform overrun. The control of overrun is very important and should be maintained as nearly constant as possible from batch to batch.

ii) The per cent overrun: The percent overrun in different types of ice creams is given in Table

iii) Failure to obtain the desired overrun: Due to the following factors one fails to obtain overrun in ice cream

•  Longer time to obtain overrun.
•  Too high drawing temperature.
•  Very soft ice cream.
•  Tendency to form ice cream with coarse texture because of large is crystal formed.

 iv) Method of calculating percent overrun: There are following two methods by which the percent overrun can be calculated.

1)      By volume

% Overrun = ((Volumeof ice creasm)-( Volumeof mix))/( Volumeof mix)*100

10 litres of ice cream mix are frozen to make 19 litres of ice cream” What is the overrun in the ice cream.”

Volume of ice cream mix = 10 litres

Volume of ice cream = 19 litres

 % Overrun = ((Volumeof ice creasm)-( Volumeof mix))/( Volumeof mix)=((19-10)/(10))*100

                                                                                                                                   =90%

2)      By weight

Weight of unit      Weight of same unit

((Volumeof mix – Valumeof ice cream)/ (Weight of unit valume of ice cream))*100

Weight of 100 ml of ice cream mix = 110 gm

Weight of 100ml of frozen ice cream = 55 gm

What is the % overrun in ice cream?

Wt. of unit vol. of mix –Wt. of same unit vol. of ice cream

% Overrun =((Wt.of unit vol.of mix –Wt.of same unit vol.of ice cream)/( Weight of same unit volumeof ice cream))*100

((110-55)/55)*100 = (55/55)*100 =100%