I understand that a higher OG beer = more alcohol, but what truly dictates a high OG beer from a low OG? Will a stout with the same ABV have more OG than a Pilsner with the same ABV?
In: Chemistry
ABV is derived from the difference between the OG and the final gravity. The specific gravity is a measure of, in this context, sugar content. The note sugar you start with, the more there is for yeast to ferment into alcohol. The less sugar you finish with, the more of it *was* fermented.
High OG doesn’t automatically lead to higher ABV. Depending on factors such as sugar sources, mash temperature, choice of yeast strain and so on, a lot of sugar may be left unfermented. If you’ve ever had a beer described as having a lot of body, chances are this had high starting and high finishing gravity. The body comes from there being residual sugars in the beer that was never fermented.
Two things will dictate the gravity of a beer: How much sugar is used (this includes all of the grains used) and what kind of yeast is used to ferment the beer. the gravity is partially (mostly) based on how much alcohol is in the beer and partially (minimally) based on what else is dissolved in the beer (effectively coloring, flavoring, texture, which is a byproduct of the sugars and the yeast)
The sugars can come from many sources: grains, rice, corn, kane sugar. This forms the basis of the flavor and texture of the beer.
The yeast will take the sugars, eat them and produce alcohol.
You will find that beers with a similar ABV will have a similar, but not exactly the same OG.
Original gravity just tells you how much sugar is in the starting beer that is available to ferment. Higher original gravity means more potential fermentation, so higher potential final alcohol percent.
Latest Answers