SRM is used to measure color according to the Lovibond scale. Higher values of color measurement correspond to darker beers.

IBU is the International Bitterness Unit, measuring the bitterness of the beer from the hops. One IBU corresponds to 1mg of alpha acid per liter of beer.

OG stands for "Original Gravity". This is the specific gravity of the unfermented wort. The primary contributor to specific gravity is sugar, some of which is fermented into alcohol, and some of which remains in the finished beer to give sweetness and body.