Refractometer alcohol correction question

[ajdelange]

My recollection is that ProMash lets you dial in a correction factor. OTOH I tried the MoreBeer calculator on the limited data set I have (7 beers) and found it generally pretty good. The worst error was about 1 °P.

I found that when I converted nD readings to Brix readings yesterday I accidentally used the vacuum based conversion when I should have used air. Redoing the numbers on my limited sample I found that the MB spreadsheet returns an FG that is, on average 2.75 points larger than the actual FG (every single result was too large). The rms error is 3.2 points and the largest error 6 with a couple of 3's and 4's. My mistake yesterday gave better agreement! Bear in mind that this really only pertains to the beer set I've tested. Another set of beers might give closer (or worse) agreement.

[Thirsty Boy]

Pro mash does make the correction for you, but you need to be using the fermentation calculator in the "session" feature. It will get you pretty damn close to the readings you would get on your hydrometer. If I use my "economical" hydrometer, the the difference between it and the corrected refract reading is a non event... With my good hydrometer, it's mostly spot on - but if you wanted to be picky it might be 1.001 out here and there. I like to take a gravity reading every day, (or thereabouts) so using the refract means I don't chew through a couple of litters of beer just in samples... If I am feeling particularly conscientious I will double check the final gravity with my good hydrometer.

[Hoppy Mad]

+1 Thirsty

I use promash in the fermentation page during a session. I also
compared the details with my hydrometer and both were the same.


Cheers

Brendan

[andy77]

+10000000000000000 to andy77!

Steelers&Beer, you're just on my side because I used to live in Roland Park.