To develop an overrun table to determine overrun quickly by weight when making ice cream, all you need is a cup with a fixed volume that is convenient for filling ice cream into (like a steel measuring cup, for example, with a flat top that would be easy to scrape level) and an ordinary gram balance. Then, using the equation from above, you can calculate what the weight of the cup would be for a series of different overruns, and then make up a table. Then when you are running ice cream, just keep weighing the cup and checking against the table for the overrun in the cup.

% Overrun = (Wt. of mix - Wt. of same vol. of ice cream )/Wt. of same vol. of ice cream x 100%

So, lets say your cup holds 100 mL. Fill the cup with mix and weigh it. Let's say the net weight (minus the weight of the empty cup) is 110 g. Lets say the empty cup weighs 30 g.

The net weight of the cup at 5% overrun would be:

.05 = (110 - x)/x, solve for x and you get 104.8, so the gross weight would be 134.8 g.

*{In case your algebra is rusty, to solve for x, follow this example:
.05 = (110-x)/x
x = (110-x)/.05
x = 110/.05 - x/.05
x = 2200 - 20x
x + 20x = 2200
21x = 2200
x = 2200/21 = 104.76}*

Likewise for 10%, 0.1 = (110 - x)/x, solve for x and you get 100, so the gross weight would be 130 g.

Keep going up to 150% or so, then make a table:

Overrun% Weight of cup + ice cream (grams)

0 140

5 134.8

10 130

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150 74