Is there a way to figure ABV?

So here is the deal. I didn't take a hydro reading before fermentation. I was wondering if there is a way I can find out. I have a triple scale hydro that has %ABV, does anyone know if this is accurate?

No. In order to figure out ABV, you need a before and after measurement. All you are doing with a triple scale is taking a before and after reading and doing the math. The trip scale just has ABV readings, to make the math easier.

The closest thing you are going to get is if you enter your recipe into a program like Promash, and that is only going to give you an estimate.

Ok thanks.

Cant you use a hydrometer and a refractometer and use the difference between the readings to figure out ABV?

take the difference of your OG and your FG and multuply by 0.129

i.e - OG 1.040 and FG of 1.008 = 32
-- 32 x .129 = approx 4.1 ABV

Hey man, I'm sure there is someway to measure ABV without a before reading, but you will need some sort of expensive scientific equipment probably, not just your average hydrometer.

Well, the easiest way (if it's an extract brew) to do it is to estimate the og. As someone else said, use brewing software (or do the math, but I'm mathmatically challenged) and estimate your o.g. Then use the actual f.g. and you'll have a pretty good idea of ABV.

Yooper Chick said:

Well, the easiest way (if it's an extract brew) to do it is to estimate the og. As someone else said, use brewing software (or do the math, but I'm mathmatically challenged) and estimate your o.g. Then use the actual f.g. and you'll have a pretty good idea of ABV.

Click to expand...

Yup...pretty easy especially if you are brewing primarily extract and don't have to worry about estimating efficiency.

http://hbd.org/uchima/tech/gravity.html

Estimating OG from Ingredients
To estimate the OG of a recipe, multiply the PPG rating of each ingredient by the number of pounds of that ingredient, and sum the results for each ingredient. Divide this total by the number of gallons of wort you are making (including top-up water, if any). The result will be the estimated OG, in points.

Example:
A 5 gallon recipe calls for 6 lbs of dried malt extract and 1 lb of steeped crystal malt; what will the OG be?

( ( 6 lbs DME x 45 points ) + ( 1 lb of crystal x 32 points x 0.70 efficiency ) ) / 5 gallons = 58

So we would expect the original gravity to be approximately 1.058.


Figure a decent estimate of:
DME - 45
LME - 38

Edit: or try this:
http://www.brewhaus.com.au/html/Calculators/ExtractGravity.html

Thanks for all the input, I will try to figure it out. I was worried because when I took the FG measurement it said 2%ABV...and I thought wow I almost made NA beer. So once again thanks for the help, and yes the was a primarly extract brew with steeping grains.

Here's my method.

Fast for 5 hours.

Drink one full glass of brew-in-question on empty stomach.

Take a guess...

after estimating OG...

(og-fg)*131=ABV