refrac trouble

[sharkguy05]

Ok so I have been getting way in accurate readings with my refrac. I have calibrated it 2x and checked its at 0 Brix with distilled water. I used beersmith tool and took a refrac reading and a hydro reading and calibrated the refrac option. So I took a reading of my beer that seemed like it was done fermenting and refrac said 6.4 which in beer smith with an og of 1.052 would be about 1.012. So i kegged it and I took a sample to taste. It seemed a little sweet so i pulled some off and took a hydro reading. it said 1.020, way to high for a hefe. So went thru the steps again a calibrated the refrac. I just took a reading of that beer after letting it ferment more and it said 6.2 brix which according to beersmith should be 1.008! little dry but good. I took a hydro to be sure and its 1.016......is there something I am not doing right or is my refrac fucked up. Any help would be appreciated....while i like the convience of a refrac im seriously considering going back to just hyrometer. Thanks guys

[Mills]

I get the same thing help us.

Mills

Ok so I have been getting way in accurate readings with my refrac. I have calibrated it 2x and checked its at 0 Brix with distilled water. I used beersmith tool and took a refrac reading and a hydro reading and calibrated the refrac option. So I took a reading of my beer that seemed like it was done fermenting and refrac said 6.4 which in beer smith with an og of 1.052 would be about 1.012. So i kegged it and I took a sample to taste. It seemed a little sweet so i pulled some off and took a hydro reading. it said 1.020, way to high for a hefe. So went thru the steps again a calibrated the refrac. I just took a reading of that beer after letting it ferment more and it said 6.2 brix which according to beersmith should be 1.008! little dry but good. I took a hydro to be sure and its 1.016......is there something I am not doing right or is my refrac fucked up. Any help would be appreciated....while i like the convience of a refrac im seriously considering going back to just hyrometer. Thanks guys

[ajdelange]

No, there is nothing wrong with your refractometers. There is something wrong with the correction. At best a different correction formula is required for each type of beer that is being measured. For example, MEBAK has separate formulas for Voll and Stark beers. And neither of these fits all Vollbiers or all Starkbiers. Refractometers are fine for monitoring changes in extract during lautering and for determining when fermentation is ended by observing no change from day to day but you really can't expect to get a terribly accurate reading of remaining extract or alcohol content from them unless they are calibrated for each beer against an accurate instrument of some other type. This is what is done in commercial brewing but it is not practical for the home brewer. For important measurements you should use a hydrometer.

[CRBrewHound]

What it really boils down to is that alcohol is lighter then water so it screws up final gravity readings because the refractometer does not know that there is alcohol in the solution. As stated above what you should do is use the refractometer for all of you initial stuff and a hydrometer for final measurement.

[brewinhard]

What it really boils down to is that alcohol is lighter then water so it screws up final gravity readings because the refractometer does not know that there is alcohol in the solution. As stated above what you should do is use the refractometer for all of you initial stuff and a hydrometer for final measurement.

+1. It saves all the futuristic math formulas one has to do to get an accurate reading.

[sharkguy05]

True.... I knew it didnt account for alcohol n there was equations but i figured thats what beer smith was for. So then whats the point of the refrac tool in bs? While im no j at math im also no palmer either lol

[ajdelange]

It isn't that alcohol is lighter than water (which it is) that is responsible here but that it has a higher refractive index than water. Thus if you add alcohol to water the RI of the solution is higher than that of water. If you add sugar to water it also increases the refractive index. Thus as a beer ferments the reduction in extract (sugar) lowers the RI while the introduction of alcohol raises it. The various tools try to compensate for this. The problem is that there is no single formula that does this accurately for all beers.

[CRBrewHound]

True.... I knew it didnt account for alcohol n there was equations but i figured thats what beer smith was for. So then whats the point of the refrac tool in bs? While im no j at math im also no palmer either lol

I am pretty sure that Beersmith just uses an offset to account for alcohol, which isn't very accurate. However, if you really like the convience of the refracometer and don't want to mess with the hydrometer. There are some fairly accurate tables out there that if you know the starting OG and then take the FG with the refractometer. All you have to do is look it up in the table and it accounts for the alcohol in the solution and from the literature I have read will get you to within 0.3 ABV of actual.

You can find speadsheets online that will do this for you, web sites and even some mobile apps out there.