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The aim of the study was to characterise, quantitatively and qualitatively, the yeast microbiota found during spontaneous fermentation of grape musts obtained from the red grape varieties 'Rondo' and 'Regent'. For the research, grapes originating from two vineyards (Srebrna Góra and Spotkaniówka) located in southern Poland were used. Musts of the studied grape varieties provided a favourable environment for the growth of microorganisms. Musts obtained from fruits from the Spotkaniówka vineyard were characterised by a higher overall number of yeasts. A maximum number of cells were recorded from the fourth to the ninth day of the process, in all of the analysed musts. The growing season of 2013 proved to be the least favourable for the growth of microorganisms on grapes, which resulted in their smaller number in the batches during spontaneous fermentation. During the process, succession of different groups of yeasts was observed. It was initiated by Hanseniaspora uvarum and Candida railenensis strains, which, with the progress of spontaneous fermentation, were replaced by Saccharomyces cerevisiae strains. Metschnikowia pulcherrima and Pichia membranifaciens yeasts were identified at both the beginning and the end of the process. During fermentation, Zygoascus meyerae, Kluyveromyces lactis and Nakazawaea ishiwadae strains were also identified.

In brewing industry, adjuncts may replace malt, but they may also represent a raw material for brewing beer demonstrating different, specific organoleptic qualities. Triticale grain may give good quality malts, characterised by high extraction capacity, high diastatic power and short saccharification time. The purpose of the research was to determine the impact of triticale malt application on physiochemical composition and profile of volatile compounds in beer. In fermented wort, the content of ethyl alcohol, extract, sugars, general acidity, colour, haze, free aminonitrogen and volatile compound profile (GC-SPME) was determined. Beers produced from the triticale malt or with use of a malt mixture were characterised by higher acidity and lower ethyl acetate butanol and isoamyl alcohol. The worts analysed in the process demonstrated parameters normative for pale malts. The triticale malt may be an alternative for barley malt.Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Biodiversity of native yeasts, especially in winemaking, has hidden potential. In order to use the value of non-Saccharomyces strains in wine production and to minimise the possibility of its deterioration, it is necessary to thoroughly study the yeast cultures present on grape fruits and in grape must, as well as their metabolic properties. The aim of the study was to characterise the yeast microbiota found during spontaneous fermentation of grape musts obtained from grape varieties 'Rondo', 'Regent' and 'Johanniter'. Grapes from two vineyards (Srebrna Góra and Zadora) located in southern Poland were used for the research. Succession of subsequent groups of yeasts was observed during the process. Metschnikowia pulcherrima yeasts were identified both at the beginning and the end of the process. Hanseniaspora uvarum, Wickerhamomyces onychis and Torulaspora delbrueckii strains were also identified during the fermentation. Torulaspora delbrueckii and Wickerhamomyces onychis strains were identified only in grape musts obtained from grapes of the Zadora vineyard. These strains may be characteristic of this vineyard and shape the identity of wines formed in it. Our research has provided specific knowledge on the biodiversity of yeast cultures on grapes and during their spontaneous fermentation. The research results presented indicate the possibility of using native strains for fermentation of grape musts, allowing to obtain a product with favourable chemical composition and sensory profile.

Besides providing bitterness to beer, hops also impart a whole range of aromas, such as herbal, spice, floral, citrus, fruity and pine to this beverage. Although hops are usually added in relatively small amounts, they have a significant impact on the sensory characteristics of the product. Raw hop aroma significantly differs from the aroma resulting from its addition to the beer. The final aroma of the beer arises from substances in the malt, hops, other additives, and yeast metabolism. The biochemical transformation of hop compounds by yeast has become more and more popular in recent years. Knowledge of this process may allow more precise control over the final sensory characteristics of the beverage. The article describes the chemical composition of hops and discusses the influence of the hopping regime on the concentration of volatile compounds in the finished product. Moreover, the article describes the biotransformation of hop-derived compounds by traditionally used Saccharomyces cerevisiae yeast, as well as less commonly used non-Saccharomyces yeast. The paper outlines the current state of knowledge on biotransformation of hop-derived hydrocarbons, terpenoids, esters, sulfur compounds and glycosidically bound aroma precursors.