Wort stratification?

[worlddivides]

@DuncB @worlddivides This calculator may be helpful

View attachment 881809

https://www.northernbrewer.com/pages/refractometer-calculator

While I wasn't ready to try this on the beer in this thread, I did try it on a beer that finished fermenting and that has been in my fermenter for about 12 days now.

For reference, my initial hydrometer gravity reading was 1.041 and my initial refractometer reading was also 1.041 (initially the hydrometer was 1.040 but at a warmer temperature than the 20C/68F calibration, which was temperature adjusted to 1.041, but the refractometer's ATC function automatically changed the sample from displaying 1.040 to displaying 1.041 within a few moments of putting it on there). The final gravity was 1.007. Brewer's Friend's ABV calculator gives that as 4.46% ABV and 82% apparent attenuation.

I took some of the hydrometer sample (which was exactly 68C when I took it from the fermenter) and took a refractometer reading, which was exactly 5.0% Brix. Putting that into the Northern Brewer converter of 5.0% Brix and 1.007 current gravity gave me an ABV of 4.522% and an original gravity of 1.040.

That is quite impressive.

 

[DuncB]

Now just try it on the finished beer OG with this calculator and see how it compares. As if you hadn't got an OG ( which you didn't truly know for the beer that " stratified "

https://www.vinolab.hr/calculator/alcohol-from-hydrometer-refractometer-en27

 

[BrewnWKopperKat]

FWIW, the calculator is also in BeerSmith 3 (Tools / Refractometer)

eta: This article (link to Internet Archives) has an equation that may be the basis for all the other calculators.

 

[worlddivides]

Now just try it on the finished beer OG with this calculator and see how it compares. As if you hadn't got an OG ( which you didn't truly know for the beer that " stratified "

https://www.vinolab.hr/calculator/alcohol-from-hydrometer-refractometer-en27

Since I only had 2 bottles of it left, I was planning on waiting, but I decided I might as well drink 1 bottle and test it. But, man, I thought I must be going crazy because I was expecting around 4.1% ABV and the data I got put into that website said I had 2.84% ABV, which would be more than 1.2% lower than what my gravity readings said. I thought "There's no way" and then thought to put the same data into the Northern Brewer calculator that BrownWKopperKat listed that I had used before and it gave me 3.946% ABV, about 0.1% less than what my data said. Out of interest, I put the data for the beer I measured earlier today that's still in the fermenter and, while the Northern Brewer says 4.522% (compared to the OG and FG to ABV calculation of 4.46%), that Vinolab site says 3.71%. Not as big of a difference, but still 0.81% less than what Northern Brewer says.

So I'm not sure what's wrong with the calculations on that Vinolab site, but a 1.2% ABV difference is pretty massive.

Northern Brewer estimates my initial gravity at 1.034, which makes me think that the 1.033 that my hydrometer said was, as crazy as that seems, actually correct and probably the result of the coarse crush which even the 20 minute longer mash was unable to account for, and that the sugar I added later probably only added 2 gravity points instead of 3.