Cant make sense out of Brix and SG readings

[djonesax]

Im trying to make sense out of Brix and SG readings but things dont add up. I foolishly didnt take a hydro reading after cooling my wort so I dont have before and after SG readings using a hydrometer. I boiled the wort until I got to 1.060 SG or 14.72 brix on my refractometer. I took the readings hot but a tinty drop should cool almost instantly when dropped on the glass. Now the fermented beer is sitting at 8 brix on my refractometer and 1.017 on my calibrated hydrometer. The refractometer is calibrated also.

Northern Brewers calculator says that with an original 14.72 Brix and 8 brix current, my current gravity should be 1.014 but my hydrometer says 1.017.

If I go solely on Brix, I get an ABV of 5.95 which is great. If I use my hydrometer reading of 1.017, I get an ABV of 4.8 which it not what I wanted and it says that my OG would have been 1.053 but the refractormeter read 1.060. WFT?

How are these so far apart? What am I doing wrong here?

Thanks,

David

 

[Transamguy77]

You can't use a refractometer for final gravity, the alcohol messes with the prism. As far as final gravity a few points off isn't bad, is this extract or AG? How long has it been fermenting?

If it's extract it might be done, sometimes they don't finish to the calculated FG.

 

[ba-brewer]

I found this calculator to be pretty close.
http://seanterrill.com/2012/01/06/refractometer-calculator/

To improve the accuracy you need to taking some sample measurements to come up with your wort correction factor, but the default is usually pretty close.

I found I get better correlation if I flood the lens vs just a drop. A drop or two always seem to read higher for me.

 

[doug293cz]

I found this calculator to be pretty close.
http://seanterrill.com/2012/01/06/refractometer-calculator/

To improve the accuracy you need to taking some sample measurements to come up with your wort correction factor, but the default is usually pretty close.

I found I get better correlation if I flood the lens vs just a drop. A drop or two always seem to read higher for me.

The problem with dropping a very small hot sample on the refract plate is that a significant amount of water can evaporate before you get your reading. This will give you a high reading. My procedure is to take about a 2 oz sample (turkey baster) put it into a room temp cup, cover the cup immediately, then after a minute or two, use a dropper to sample from the earlier "large," but now cooler, sample to put on the refract. Less chance of overly high readings that way.

Brew on

 

[djonesax]

You can't use a refractometer for final gravity, the alcohol messes with the prism. As far as final gravity a few points off isn't bad, is this extract or AG? How long has it been fermenting?

If it's extract it might be done, sometimes they don't finish to the calculated FG.

It's my understanding or lack thereof ABV can be determined using a refractometer but there is additional math involved.

I used this calulator at https://www.brewersfriend.com/refractometer-calculator/

 

[djonesax]

The problem with dropping a very small hot sample on the refract plate is that a significant amount of water can evaporate before you get your reading. This will give you a high reading. My procedure is to take about a 2 oz sample (turkey baster) put it into a room temp cup, cover the cup immediately, then after a minute or two, use a dropper to sample from the earlier "large," but now cooler, sample to put on the refract. Less chance of overly high readings that way.

Brew on

Thanks, I'll remember that.