Examination of the relationships between original, real and apparent extracts, and alcohol in pilot plant and commercially produced beers

Anthony J. Cutaia, Anna-Jean Reid, R.A. Speers

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    15 Citations (Scopus)

    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 A(w/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 A(w/w) and real extract values.

    Original languageEnglish
    Pages (from-to)318-327
    Number of pages10
    JournalJournal of the Institute of Brewing
    Volume115
    Issue number4
    DOIs
    Publication statusPublished - 2009

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