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====Temperature and Growth Rate====
While very warm fermentation temperatures have an impact on the speed of potentially attenuation of kveik, temperatures on the higher end of the scale can have a slightly negative impact on the growth rate of some kveik cultures. [https://nmbu.brage.unit.no/nmbu-xmlui/handle/11250/2681970?show=full Aasen's Master's thesis] reported that for all three kveik cultures tested (Ørjasæter, Gamlegrua, and Gausemel) the growth rate was slightly higher when incubated at 22°C and/or 30°C compared to being incubated at 37°C. They were also higher than the optimal growth of US-05. The cultures tended to reach peak cell growth at around day 2 or 3, and then experienced a slight decline until day 7, with this decline after day 2 or 3 being slightly steeper at the hotter incubation temperature of 37°C. The warmer incubation temperature of 37°C did not result in faster growth than the cooler temperatures of 22°C and/or 30°C. Therefore, for optimal growth of kveik for starters or yeast labs, a temperature of 22°C or 30°C might be optimal for some kveik cultures <ref name="Aasen" />.
[https://www.biorxiv.org/content/10.1101/2021.07.26.453768v1 Foster et al. (2021)] found that not only do kveik strains grow faster at higher temperatures, but they generally also survive better than typical brewing yeasts at 35-42°C. It was first postulated by the researchers that this could be due to higher glycerol production in kveik strains versus regular brewing strains, but the researchers found the kveik strains produced generally the same amount of glycerol as regular brewing strains. The researchers then discovered that the tested kveik strains produced much higher levels of trehalose, which is a carbohydrate used by yeast (and other organisms like frogs) to protect cells from freezing/thawing and higher temperatures. Unlike other brewing strains which break down trehalose at the end of fermentation, kveik keeps it. This might be at least one reason why kveik strains are able to tolerate higher temperatures (there may be other currently unknown qualities of kveik that also assist with temperature tolerance), as well as why they can tolerate drying. It might also explain why kveik begins to ferment so quickly in fresh wort. Trehalose stores also cause yeast to not take up maltotriose, and this might explain why kveik strains tend not to consume maltotriose <ref name="Foster_2021">[https://www.biorxiv.org/content/10.1101/2021.07.26.453768v1 Kveik brewing yeasts demonstrate wide flexibility in beer fermentation temperature and flavour metabolite production and exhibit enhanced trehalose accumulation. Barret Foster, Caroline Tyrawa, Emine Ozsahin, Mark Lubberts, Kristoffer Krogerus, Richard Preiss, George van der Merwe. bioRxiv 2021.07.26.453768; doi: https://doi.org/10.1101/2021.07.26.453768]</ref> (see also [https://www.facebook.com/groups/MilkTheFunk/posts/4824280584266784/ this MTF thread by Richard Preiss]).