Browsing by Person "Einfalt, Daniel"

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Barley-sorghum craft beer production with Saccharomyces cerevisiae, Torulaspora delbrueckii and Metschnikowia pulcherrima yeast strains
(2020) Einfalt, Daniel
The use of different yeast strains contributes to obtain insights into beer products with diverse sensory characteristics. In this study, three yeast species of different genera were selected to evaluate their fermentation performance and sensory profile for barley-sorghum beer production. Baley-sorghum wort was produced with 12.5°P and fermented with Saccharomyces cerevisiae, Torulaspora delbrueckii and Metschnikowia pulcherrima yeast strains. Differences were observed in terms of fermentation time and ability to ferment maltose. S. cerevisiae attenuated initial maltose concentration within 72 h, while M. pulcherrima and T. delbrueckii performed fermentation within 120 and 192 h, respectively. Both yeast strains simultaneously produced 11% and 23% lower ethanol concentrations, compared to S. cerevisiae with 37.9 g/L. Wort fermented with T. delbrueckii showed residual maltose concentration of 19.7 ± 4.1 g/L, resulting in significantly enhanced beer sweetness. S. cerevisiae produced significantly increased levels of higher alcohols, and obtained the highest scores for the sensory attribute body perception. Beer produced with T. delbrueckii contained significantly lower fermentative 2,3-butanediol and 2-methyl-1-butanol volatiles; this beer also showed reduced body perception. Beer conditioned with T. delbrueckii was significantly preferred over M. pulcherrima. Besides S. cerevisiae with high fermentative power, T. delbrueckii and M. pulcherrima were found to have reduced maltose fermenting abilities and provide significantly different sensory attributes to barley-sorghum beers.
Effect of partial condensation (dephlegmation) in fruit brandy distillation equipment on the composition of apple brandies
(2025) Yagishita, Manami; Reber, Oliver; Alter, Daniela; Kölling, Ralf; Einfalt, Daniel; Chinnici, Fabio
Fruit brandy equipment commonly uses partial condensation (dephlegmation) to generate reflux in the distillation column. Here, we examined the effect of dephlegmation on the composition of fruit brandies in both lab-scale and large-scale settings. In lab-scale experiments, the dephlegmator led to a pronounced enrichment of ethanol in the distillate due to preferred condensation of water, while the concentration of flavor compounds was differentially affected. Some compounds were enriched in the distillate, some were depleted, and some were unaffected by dephlegmation compared with the control without a dephlegmator. Large-scale fruit brandy equipment relying exclusively on dephlegmation was compared as standard with an enrichment section containing three trays. In the equipment relying on dephlegmation, tail components such as fusel alcohols were less well separated from the middle run, which led to a reduced yield of clean spirit in the middle run. In triangle tests, the spirits from the two devices could be clearly differentiated, but there was no clear preference for one spirit or the other. This study provides for the first time detailed data on the influence of dephlegmators on the behavior of flavor compounds during fruit brandy distillation.
Production of coffee cherry spirits from Coffea arabica varieties
(2022) Blumenthal, Patrik; Steger, Marc C.; Quintanilla Bellucci, Andrès; Segatz, Valerie; Rieke-Zapp, Jörg; Sommerfeld, Katharina; Schwarz, Steffen; Einfalt, Daniel; Lachenmeier, Dirk W.
Coffee pulp, obtained from wet coffee processing, is the major by-product accumulating in the coffee producing countries. One of the many approaches valorising this underestimated agricultural residue is the production of distillates. This research project deals with the production of spirits from coffee pulp using three different Coffea arabica varieties as a substrate. Coffee pulp was fermented for 72 h with a selected yeast strain (Saccharomyces cerevisiae L.), acid, pectin lyase, and water. Several parameters, such as temperature, pH, sugar concentration and alcoholic strength were measured to monitor the fermentation process. Subsequently, the alcoholic mashes were double distilled with stainless steel pot stills and a sensory evaluation of the products was conducted. Furthermore, the chemical composition of fermented mashes and produced distillates were evaluated. It showed that elevated methanol concentrations (>1.3 g/L) were present in mashes and products of all three varieties. The sensory evaluation found the major aroma descriptor for the coffee pulp spirits as being stone fruit. The fermentation and distillation experiments revealed that coffee pulp can be successfully used as a raw material for the production of fruit spirits. However, the spirit quality and its flavour characteristics can be improved with optimised process parameters and distillation equipment.