Laboratory-Scale Production of High-Gravity Wort Suitable for a Broad Variety of Research Applications

Abstract

A laboratory-scale high-gravity wort production protocol was developed. Currently, wort production and consequently, much of brewing research, is confined to breweries and specialized research institutions that possess the specialized brewhouse equipment needed to produce wort. A wort production protocol was designed around the nonspecialized equipment found in a typical bioprocess-engineering laboratory. Malted barley was ground in a hammer mill to produce a grist suitable for a mash tun vessel. Mashing and filtration were performed in a stirred, temperature-controlled fermentation vessel fitted with a simple mesh filter. A mash with a liquor/grist ratio of 3.3:1 produced a wort with a specific gravity of at least 22.74°P with an extraction efficiency of 89.7% in less than 335 min. Furthermore, the wort was shown to be fermentable, having a 73% attenuation limit when fermented with Saccharomyces cerevisiae NCYC 1338. The worts produced contained high levels (303 mg/L) of free amino nitrogen, had an average pH of 5.01, a color of 33.85 EBC units, and bitterness of 19.7 BU. This protocol can be used for almost any research application, including the comparative study of fermentations on the basis of all-malt wort, high-gravity malt wort and high-gravity adjunct wort. Furthermore, the protocol will enable researchers outside of the brewing industry to bring their specialized skills to brewing research.