Beer Math Question

[william_shakes_beer]

I realize there is software out there to do the heavy lifting. However, I find that understanding the concepts makes me a more intuitive brewer. Sooooo;

If I have an OG of 1.052 and am using a yeast that attenuates an average of 74%, will the predicted final gravity be((1- .74)*.052)+1=1.01352 or is there something more that has to be considered in the equation?

 

[Homercidal]

You have to also consider the fermentability of the wort. Mashing higher makes a beer less fermentable, and mashing lower makes it more fermentable. If you are using extract, you don't really have much control over the fermentability, but you could probably get that information from the producer.

 

[brushvalleybrewer]

The other thing would be if the recipe includes any simple sugars. The yeast attenuation number is for maltose. Beer yeast will typically ferment 100% of simple sugars. That is why some brewers use them in beers they want to finish dry.

Typically though, the formula you are using is the right one.