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vera 02-16-2012 12:37 PM

refractometer question
I understand that you can't use a refractometer on fermented wort. Is there a formula that will compensate for the alcohol?

Haputanlas 02-16-2012 02:08 PM

If you don't know the OG, you won't know the alcohol. However, I assume it would be possible to figure out the OG if you had the FG and the ABV.

tv187u 02-16-2012 02:15 PM

There is a formula thAt allows you to measure fermenting wort. I however don't know it since I use 'beer smith' which has a function for that. I have heard that it isn't very accurate, though. I always use a hydro once yeast has been pitched.

Vale 02-16-2012 02:40 PM

The formula is:

Current Gravity = 1.53 X Current_Refractometer_Reading - 0.59 X Original_Gravity

OG will have to be expressed in degrees Brix (or Plato, whatever unit your refractometer uses) too!



petrostar 02-16-2012 03:48 PM

Just google refractometer calculator. I've used my refractometer for a year now. It is very accurate and allows for constant testing of the beer with minimal risk. I pulled hydro samples the first 6-7 batches to verify its accuracy. Make sure you account for temperature on both OG and FG, it makes a difference.

kh54s10 02-16-2012 03:52 PM

I ahve used a couple of calculators that I found by googling. They gave ma an idea of what the gravity was post fermentation but I didn't find them to be terribly accurate.

Spartan1979 02-16-2012 04:41 PM

I've found the calculators to be fairly accurate, usually within a couple of points. I just use mine to give me an idea of where I'm at. I take the "official" FG reading with a hydrometer.

hough77 02-16-2012 06:09 PM

The app "Brew Pal" has the alcohol correction for refractometer's and hydrometer corrections, amongst other goodies! I use an iPhone, don't know about Android or Blackberry.

RoadKing 02-17-2012 10:15 AM

I use this spreadsheet from Morebeer http://morebeer.com/learn_vids/vids_refract
The link to Download in under video. I know alot of people say it's not accurate with alcohol present, but when I double check it against hydrometer its allways correct.

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