Help With Refractometer Readings

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The Village Idiot

Well-Known Member
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Hi all,

First problem, the scone burner broke the hydrometer...GGGRRR

On a positive the new refractometer has arrived.

Second problem, how the hell do you adjust a refractometer reading to account for alcohol.(FG)

I have a Brown Ale that shows 1.025 @ 22C and a Swiss Lager that shows 1.019 @12C

Have racked them both.

There are some graphs floating around the site about alc adjust but jeeez they confuse the shit out of me.... too many dead brain cells I suspect.

What to do??

Most people tend to use the refractometer for brewing and prior to pitching yeast, then go the hydrometer once fermentation has started. But MXD's link will work, if u know the OG.
Sorry about your hydo. :(
Broke my last hydrometer years ago!

Some tips I have figured so far(using my refractometer):
When taking a reading, make sure there are no air bubbles or particles in your sample.
Calibrate with distilled water to read zero before reading.
Rinse off calibration water with your sampled wort/beer.
Take a few samples and average them out.
You can get ball park readings at high temps right out of the kettle, but I try to take readings closer to room temp if possible - so cool them.

To calculate SG, I have a free iPhone app called BrewCalc. I also use iBrewmaster and Promash calculators. All of these have a function built in to allow for fermenting/fermented wort. I'm not sure how the formula works?

Knowing refractometers measure the light refraction through a liquid and reference this to a gravity of the said liquid... Does anyone think the light wavelength would make a difference to the reading? If so, would measuring under artificial light (various light bulbs like fluro,led etc...), change the reading to sunlight? I find the line to be blurry under the shed's fluro by 02 to 0.4 brix and step outside to get a sharper line to read the refraction.

red is edit text
Thanks for the replies......

JazzaFish, my uneducated guess would be natural light would be the go.... dont imagine flouro or other internal light would refract the same way as natural.

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