Overrun
Overrun is the increase in product volume, expressed as a percentage, resulting from the entrapment of air in liquid mix as it is frozen.
The rotating dasher blends air into the mix as it is frozen resulting in increased frozen product volume. For example, if one gallon (1) (4.4 liters) of liquid mix is poured into a freezer and one and a half gallons (1/2) (6.6 liters) of frozen product is drawn out, the result is a fifty percent volumetric increase, or a fifty (50%) percent “overrun”.
Why is overrun important? The introduction of air into the finished frozen product is essential from two stand
points...taste and profitability. Frozen product with a low percentage of overrun costs more to serve, appears wet and is heavy. The introduction of air makes the finished frozen product taste richer. Too much air causes the finished product to be too light and fluffy, making it less satisfying and adversely affecting sales.
The optimum percentage of overrun varies from one type of mix to another, but 50% overrun seems to be a good average. The ingredients in some mixes take on and hold air easier.
Overrun also effects profitability. For example, an increase from 25% to 50% overrun represents a mix savings of 17%.
Uniform overrun insures consistent portion costs. If overrun is allowed to drop, it will cost more to serve a portion of finished product.
Computing Overrun
1.Weigh an empty cup.
2.Weigh this cup filled with liquid mix, subtract the weight of the cup.
NOTE: Repeat this step only when changing mix sources, as mix weight will vary slightly from one supplier to another.
3.Draw a heaping cup of frozen product that contains no air pockets. NOTE: Use a spatula or other device to help fill the cup completely. Avoid tamping the cup as this artificially reduces overrun.
4.Use a straight edge to scrape off excess product flush with the rim of the cup and weigh the cup.
5.Subtract the cup weight and use the overrun formula to determine overrun.
Weight of Liquid Mix (Minus) Weight of Frozen Product
x 100 = OVERRUN
Weight of Frozen Product
For Example:
If a full cup of liquid mix weighs 23 ounces and a full cup of frozen product weighs
23 -
x 100 = 48.4% Overrun
NOTE: Several companies manufacture scales that automatically read out the overrun for one pint samples. A scale of this type is a valuable tool and should be part of any well run operation. A trick is to place the empty cup on the scale and zero it out first, this will then automatically eliminate the weight of the cup from the calculation.
Overrun has a major impact on the size of the finished frozen portion. As the percentage of overrun (air in the frozen product) increases, the size of the finished portion also increases, yet the portion weight remains the same. For example, an increase from 25% to 50% overrun will yield a 20% larger portion. Customers equate size with perceived value so proper overrun will result in increased customer satisfaction. Experiment with carburetor settings to achieve optimum overrun and product quality with each mix. Some products such as Cappuccino taste better with low overrun. Experiment with different carburetor settings to find the ideal combination for each product.
Crathco® 5512 Manual | Page 7 |
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