Forgot to take OG reading...

[injac]

Hi All,

Is there a way to roughly estimate the OG of a beer if like a plonker you forgot to take a reading before pitching the yeast and heading out for the day?

I do have the pre boil gravity if that helps...

[BrannigansLove]

You should be able to calculate the SG if you have the preboil gravity, and volumes pre and post boil.

[Fil]

if your generally on target for both gravity and volume its a safe bet your within a few points with this brew too

if you take a reading asap, you will know the OG was at least that value

[gnorwebthgimi]

The best way to calculate the original gravity in this circumstance is using the Intoxication Per Beverage ratio factored by your individual alcoholic beverage consumption constant plus the final specific gravity.

Expressed as a formula OG = FSG + 0.1/IPB ratio + (0.010 x IABC constant)

A quick example of the calculation:

Let's assume an FSG of 1.015 and it takes you six pints of this beverage to achieve drunkenness (I won't provide the exact definition if drunkenness but if you can follow the calculation and you care what the OG of the beverage is: then you are not drunk) and let's assume you are a light-weight so your individual alcoholic beverage consumption constant is 1.25 (rather than a heavy weight with a higher IABC)

FSG = 1.015
IPB ratio = 0.1 /6 = 0.017
+ 0.010 x IABC 1.25 = 0.013

OG = 1.045

Alternate methods
If you can acquire a vinometer you could calculate the OSG from the ABV and the FSG but that involves a lot of guess work.

I hope that helps.

[Rhodesy]

Wonderful

[gnorwebthgimi]

If you can provide the grain bill, volume of wort collected, final specific gravity and yeast used then it would be possible to make a drunken/educated guess of the OG.