The Beer Board (A Primer)

The St. Francis Brewery Beer Board

You may have seen this board outside the brewhouse.  You may also wonder what the heck some of these numbers mean. 

This board exists for several reasons.  For most of you, it serves to tell you what beers are on tap, and when they were tapped.  For you "beer geeks" out there, there are a few more numbers that provide information about the beer.

I love beer geeks.  I am one.  I want you to be one too.

Let's start with the the column "O.G."  This stands for Original Gravity.  Gravity is a measure of the percentage of sugar in a solution.  Brewers, Winemakers, and fruit juice producers all measure gravities of their products.  The original gravity is a measure of the sugar content before fermentation occurs.  The original gravity will always be higher than the second number, "F.G." or Final Gravity.  Once we add the yeast, the yeast will start eating the sugar to reproduce.  As the sugar is consumed, the alcohol levels rise.  Eventually there's not much food (sugar) left for the yeast and they start to become dormant.

When the fermentation cycle is complete, I'll take the final gravity reading.  By using a simple calculation, I am able to provide a good estimate of the Alcohol by Volume or ABV--the next column. 

Our gravities are expressed in degrees Plato.  Most homebrewers use a different scale called the Specific Gravity scale.

The higher the O.G. number, the stronger the beer will be, and vice-versa.

Thus concludes today's lesson.

Amen