Why different abv % from different calculators?

[bannerj]

Used this calc to convert my refrac readings: http://www.brewersfriend.com/brix-converter/

It says my reading of 13.8 brix comes out to 1.056 and 7.5% abv???

I adjusted my efficiency in beersmith to 79 % so that the est OG is now 1.056 and it reads est abv of 5.4% ???

I know I'm probably missing something in the fine print of either BS or brewersfriend.

 

[doug293cz]

Used this calc to convert my refrac readings: http://www.brewersfriend.com/brix-converter/

It says my reading of 13.8 brix comes out to 1.056 and 7.5% abv???

I adjusted my efficiency in beersmith to 79 % so that the est OG is now 1.056 and it reads est abv of 5.4% ???

I know I'm probably missing something in the fine print of either BS or brewersfriend.

From your linked web site: "Computes potential alcohol by volume (for use in dry wines)." [emphasis added] What this means is that if all of the sugar in the "must" (wine equivalent of wort) gets fermented, then this is the estimated ABV. Doesn't work for beer, since we almost never ferment all of the sugar in wort. BeerSmith estimates what you are likely to achieve with that OG and the yeast specified.

Brew on

 

[GoForth]

I highly recommend you use this site and calculator/spreadsheet : http://seanterrill.com.

There are several different math formulas for figuring the FG using a refractometer. I use Beersmith and find it to be an excellent brewing program, but I use Sean Terrill's spreadsheet to calculate my FG and double check it with the on line program you used.

Read the info on Sean Terrill's site. It makes sense.

 

[bannerj]

yep. I'm a bonafide dufus. In the details of brewing I just googled, "brix to OG" and used the brewersfriend calc......without reading what the hell it is (wine).

Blush. Embarrassed. Thanks for helping me READ.

I guess that imperial stout will not be so imperial.

 

[doug293cz]

yep. I'm a bonafide dufus. In the details of brewing I just googled, "brix to OG" and used the brewersfriend calc......without reading what the hell it is (wine).

Blush. Embarrassed. Thanks for helping me READ.

I guess that imperial stout will not be so imperial.

Don't be so hard on yourself. There's a lot to learn about brewing, and it often takes multiple times thru the same material before it completely sinks in and makes sense. Keep reading and asking questions (and brewing of course.)

The Brix to OG part of the calculation is ok to use, just not the starting Brix to ABV calculation. Refracts are simple to use for OG measurements, but care needs to be taken when using them after fermentation has begun. This is because the presence of alcohol also affects the index of refraction of a liquid. In order to use a refract after fermentation has started, you need to use a calculator that compensates for the presence of alcohol. The previously linked calculator by Sean Terrill is considered by many to be the most accurate available. In order for post fermentation calculations to work you must have both the current Brix reading and the original Brix (OG) reading.

Brew on