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Kveik was passed down from generation to generation within the family, and also shared among fellow brewers in the region. In this way, kveik evolved differently than the two major beer yeast genetic groups that are used in industrialized brewing. While mostly POF-, a trait that is selected for in many beer yeast strains that prevents the yeast from producing 4-vinylguaiacol phenol, other traits are reflective of how this yeast was used by traditional farmhouse brewers of the region. For example, as far back as 1621 (and probably prior), kveik was often stored dry on wooden logs called "kveikstokker" for up to a year or longerbefore being re-used in a new batch of beer, a process known as "backslopping". Kveik was typically inoculated directly into the wort by submerging the kveikstokker into the wort at 30-40°C. The wort was often high gravity of around 1.080 SG, and the beer was served just after 1-2 days of fermentation beginning at this hot inoculation temperature. The kveik was then taken from the fermenter and dried until its next use. If the kveik went sour or died, brewers would borrow kveik from their neighbors, which was another way of preserving kveik through the centuries. Kveik was sometimes also used to ferment bread. It has been proposed by Preiss et al. (2018) that this treatment has produced yeast strains that are genetically distinct phenotypically from other domesticated yeast strains used in industrial brewing in Europe <ref name="Tyrawa_2017">[https://www.frontiersin.org/articles/10.3389/fmicb.2018.02137/full Traditional Norwegian Kveik Are a Genetically Distinct Group of Domesticated Saccharomyces cerevisiae Brewing Yeasts. Richard Preiss, Caroline Tyrawa, George van der Merwe, Kristoffer Krogerus, Lars Marius Garshol. 2018.]</ref>.