Seth's ABV Equation Need Testers!

[seth8530]

Hey all! I come here because I am in need of testers to check out my derivation of an ABV equation. This equation is not necisarly meant to be an end all. But I figured it would be kind of fun to come up with my own.

There was a thread on the WMT in which I started wondering if it would be cool if we came up with our own abv equation. The thread with that discussion is linked if you are interested.


http://www.winemakingtalk.com/forum/f6/calling-all-would-scientest-38884/

Well, pretty much my previous thread on coming up with an alternative ABV equation fizzled out when we encountered that ABV is a function of an unknown ABV correction. Pretty much what I have done is built on the previous work that we discussed on this forum but came up with an empirical correction for the previous equation that makes it solvable.

Also, in the attached PDF I went through the whole derivation in math format so it is all nice and pretty. If you do not want to deal with all the math the last page has an example and the final equation(s) depending on whether or not you want to iterate the solution until it converges.

What would be extremely helpful would be if some of you guys could use the equation in your ferments and report back the results, that way we can see how they compare to other equations that are out there. I have done some comparisons myself and it seems to be fairly good.

To view the PDF change the file extension from XML to PDF. I had to change the ending on it since the forum would not let me upload it due to its dimensions and file size.

View attachment ABV equation write up - Copy.xml

 

[ajdelange]

Either the apparent extract or the true extract can be used to estimate the amount of alcohol produced by the fermentation. As apparent extract is easier to measure, it is probably the one you will use in your brewing. The formulas are A = f*(OE – AE) and A = g*(OE – TE) where A is the alcohol content by weight and f and g are slowly varying functions of the original extract. f = 0.39661 + 0.0017091*OE + 0.000010788*OE*OE and g = 1/(2.0665 – 0.010665*OE). To convert A to alcohol by volume multiply it by the specific gravity of the beer and divide by the specific gravity of pure alcohol which is 0.789.

From this it is clear that the 'factors' depend on OE and are obtained simply from polynomials in it. Everything is in Plato. The polynomials are obtained from fits to Balling's data as reported by DeClerck.