Yankee Brew News Archive

Homebrewing Corner--Mixing Trouble: Eliminating That "Fudge Factor"

Originally Published: 03/95

By: Dann Paquette

There may have been a few situations already when you've stood in your kitchen, scratching your head for a solution for a minute or two before you finally conceded defeat. "Fudge it!"

This is the greatest weakness for homebrewers. As brewers, it's necessary to keep tabs on exactly what we're doing to make the beer we want to make. However, as a professional microbrewer I now know the secret: "fudging" may be the only essential difference between home- and larger-scale brewing.

For those of you who are ready to remove the "fudge factor" from your home brewery (for those of you who don't want to, don't bother, just keep brewing!) there's a wee formula that may help in your calculations. I would suggest leaving it on your refrigerator or with your conversions and measurement tables. It's called the mixing formula and I think just about everyone has been exposed to it at one point or another in the past. It is expressed simply as:

Aa + Bb = Cc

A and B are the two quantities you will be mixing. For instance, assume A=1 gallon of 190 degree water and B=2.5 gallons of 130 degree water. Then assume a and b are the properties that correspond with the quantities you will be mixing. In this case, a=190 and b=130 . Finally, C and c are the qualities of the sum of these figures.

So A (1 gallon)a(190 ) + B(2.5 gallons)b(130 ) = Cc. One gallon of water multiplied by one hundred and ninety equals 190, 2.5 multiplied by one hundred and thirty equals 325. The mathematical expression of this example is completed below.

1(190) + 2.5(130) = 3.5c

190 + 325 = 3.5c

3.5c=515

c=147

So using the mixing formula, we get 3.5 gallons of 147 degree water. This formula is also handy for decoction mashes, determining sparge water temperature, dilution of cleaning agents and so on and so on. Happy mixing!