Whether you are a simple consumer at the supermarket or in discussion with your supplier, it is highly likely that ice cream is quantified in litres. Although this is now the commercial standard, this method of quantification presents problems that we will explain here.

Understanding overrun: weight, air and the true cost of ice cream

A crucial concept in the world of ice cream is overrun. Overrun is the air incorporated naturally (during the crystallisation process) or artificially (being injected by pumps) into the ice cream during manufacturing. This overrun is a parameter used by manufacturers to influence the texture, the taste, but also the manufacturing cost of the ice cream. An ice cream will therefore naturally contain more or less air depending on the recipe, the equipment used and the manufacturing techniques. And logically, the more air there is, the less solid matter there will be in the ice cream.

Let us put aside the impact on taste and texture, which are mostly subjective concepts, to focus on the density of the ice cream. An ice cream with low overrun will be heavier (as it is filled with more matter and less air) than an ice cream with high overrun.

We can therefore observe a weight that differs depending on the ice cream (for the same volume and the same flavour) which will give us an initial indication of the overrun rate. And weight remains the most objective criterion for comparing the quantity of ice cream we buy. This is also why it is mandatory to state the weight of the ice cream, but also not to sell an ice cream weighing less than 450 grams per litre. And to go further, only the weight is mandatory for ice cream labelling, not the volume or quantity in litres...

Because indeed, as you can imagine, air is free, and so it is the search for increased profitability that will push some manufacturers to abuse overrun.

How light ice cream distorts the number of scoops served

A common misconception among ice cream retailers is to think that the density of an ice cream or sorbet has no impact on the number of scoops that can be served from a litre. However, this is incorrect. An ice cream with a lot of overrun is a bit like a chocolate mousse or a soufflé: it seems to fill the tub well, but in reality, it contains mostly air. As soon as you dip a scoop into it, the matter compresses, the air escapes... and the volume collapses. As a result, you serve far fewer scoops than the apparent volume would lead you to believe. And that is not all: the more aerated an ice cream is, the faster it melts once served - air is not a very good insulator.