Examination of the Relationships Between Original, Real and Apparent Extracts, and Alcohol in Pilot Plant and Commercially Produced Beers

Abstract

The historical development of equations used to relate alcohol and real extract to apparent extract and original gravity, as well as ratios between the corrected Real (RDF) and Apparent Degrees of Fermentation (ADF), were examined in light of modern polynomial and non‐linear regression techniques. Comparisons were performed using an extensive data set of 532 brews obtained from commercial and pilot fermentations with statistical error analysis of these empirical relationships. New predictions of apparent extract were calculated as a function of alcohol and real extract analogous to the Improved Tabarie's formula. In addition, attempts at improving Balling's original equation model estimating original gravity from alcohol and real extract are detailed and discussed. The statistical analyses of relationships between Aw/w (alcohol by weight) and functions of OE (Original Extract), AE (Apparent Extract) and RE (Real Extract) as well as ratios between the corrected Real and Apparent Degrees of Fermentation (RDF/ADF) are reported. It is expected that this paper will be useful for brewers to more accurately estimate Aw/w and real extract values.

Balling alcohol factors from the perspective of contemporary brewing.

“…This formula was also subject to criticism lately due to interactions between sucrose and ethanol in solution (Hackbarth, 2009;2011). A detailed comparison of calculations by Balling formula and corrected formula obtained by nonlinear regression enabled to cross check and modify Balling formula by adding additional constants (Cutaia and Reid, 2009).…”

“…In the American brewing the real degree of fermentation (RDF) is calculated by: (5) where the correction factor was designed in 1979 (Cutaia and Reid, 2009). Apparent degree of fermentation remained in its original form as designed by Balling: (6) where m is the apparent degree of fermentation which was later expressed in percent.…”

“…Modifi kací velkého Ballingova vzorce se zabývalo více autorů, při-čemž se optimalizovaly jak číselné hodnoty základních koefi cientů, tak jeho rozšíření o přídavnou konstantu (Cutaia a Reid, 2009). …”

“…More authors have dealt with modifi cation of the great Balling formula using optimization of the value of the numerical coeffi cients and its extension by an additional factor (Cutaia and Reid, 2009). …”

“…The calculation is based on two directly measured values which are the relative density of beer and alcohol content, while Alcolyzer Plus works with indirect calculation by Tabarie. Because our study uses the data obtained with the help of Alcolyzer Plus the calculated data are also derived using Tabarie formula (Cutaia and Reid, 2009).…”