Passing the Test

BYOB by | Nov 2014 | Issue #94

Illustration by Ellen Crenshaw

We love to talk about brewing’s contribution to the sciences, and yet we never explore its contribution to math. We all brew using simple algebraic equations tarted up with impenetrable numerical constants, but we never look at actually significant math. So brewers, I present to you: Student’s T-Test. An intimidating formula invented by a brewery that’s a fundamental piece of modern statistics!

When statisticians crunch numbers, they traditionally want big piles of data to ensure accuracy. But what if the question is something simple, like: Did this new hop affect people’s perception of my beer? Most breweries can’t whip up thousands of opinions for a single batch of beer.

Enter William Sealy Gosset, an Oxford-trained chemist and statistician hired by Guinness to help refine its industrial brewing practices. Gosset devised this equation in 1908 to confidently answer a simple question (see above) with a small sample size. Which was huge. It meant that even a small tasting panel could yield valuable information about changes to a particular recipe.

So why wasn’t Gosset’s name on his world-changing test? Trade secrets. Guinness didn’t want its competition to know it was using math to refine its brewing techniques. Gosset eventually persuaded his bosses to let him publish his findings, but he had to use a pseudonym, hence “Student.”

You can use Gosset’s invention with your spreadsheet’s built in T-test function and scores from a few friends or competitions.

A bigger, chewier stout.
For 5.0 gallons at 1.060 OG, 20 IBUs, 30 SRM, 6.0% ABV

Malt Bill
8.0 lb. Maris Otter
2.0 lb. Flaked barley
0.5 lb. Roasted barley
0.5 lb. British Chocolate malt
0.25 lb. Acidulated malt

Mash at 153°F for 60 minutes.

0.25 oz Magnum (pellets) | 13% AA | 60 minutes
0.25 oz Progress (pellets) | 8% AA | 20 minutes

Wyeast 1084 / WLP004 Irish Ale

Ferment for 2 weeks at 66°F before clarifying and serving at a low carbonation level (2.0 volumes maximum).