Question About Attenuation and OG/FG

[stjackson]

My first batch is in bottles and conditioning in a closet, which means I have empty fermentors right now, and that's just no good.

I've been looking at a Scottish Wee Heavy kit on Northern Brewer's website for my second batch, and I have a question about some of the numbers listed with it:

The analysis predicts the OG to be 1.089. The yeast listed with the kit ingredients (Wyeast 1728 Scottish Ale) has an apparent attenuation of 69-73%. The attenuation percentage has to do with how much of the sugar the yeast will consume, right? So how do I apply my attenuation number to my OG number to predict a FG range?

My guess was that I apply my attenuation number to the ".089" part of my OG, which, assuming around 70% attenuation, gives me a FG of around 1.027. Is that right?

 

[wonderbread23]

You are correct. 1.089 to 1.027 is right at 70% attenuation. It would end up around 8.22% ABV

 

[ajf]

I agree with wonderbread23 but my experience of the attenuation figures published by Wyeast and white Labs is that their figures are way lower than my results. Obviously my worts and fermentation procedures are different than theirs, but I get consistent results, so I'm not worried. When trying a new variety of yeast however, I do have to make a few brews to determine what attenuation I will get.

-a.