Stupid question re: FG

[Halbrust]

If you let a commercial beer go flat and test the gravity, is that a true representation of what the FG of the beer is/was?

 

[frazier]

If you also know the ABV%, then yes.

 

[Trail]

Yep... otherwise it wouldn't be the final gravity.

Of course, this tells you nothing if it's a blend (like Yuengling's Black & Tan). Similarly, if they bottle condition there may be a tiny (tiny) amount of play due to the fermentables used to carb, but this is supposedly around a 0.003 difference.

 

[Halbrust]

I said it was a stupid question... I just wanted to make sure I wasn't missing something obvious.

 

[frazier]

I guess it was me that was missing something obvious - I thought you were trying to determine the OG - for which you would need the ABV.

Carry on.

 

[Trail]

It's still helpful advice, though. With the FG and ABV, you can derive the OG. In the states, beer percentages listed on the bottle must be accurate within 0.3%, by law... so you won't get the hardest numbers imaginable, but a very useful guideline if you're trying to fill out a clone recipe.