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→Kveik Ring/Kveikstokk and Drying
As Norwegian farmhouse brewers only brew 2-3 times per year, kveik has adapted to being dried and stored for long periods of time in-between usage, which is unique among most domesticated yeast <ref name="garshol_preiss_mbaa" />. Storing the kveik in a dried form allows the yeast to survive longer than if it is kept as a wet slurry, and might help prevent contaminants from surviving. Wooden carvings are used to store dried kveik. Their use is simple: drag the kveik ring (more broadly known as a "twisted torus" <ref>[https://www.academia.edu/38819003/Scandinavian_Yeast_Rings_-_the_curious_case_of_the_Twisted_Torus "Scandinavian Yeast Rings - the curious case of the Twisted Torus". Susan Verberg. 2019.]</ref>, or more specifically called a "gjærkrans" or "yeast wreath" in Norwegian when used for yeast <ref>[https://twitter.com/larsga/status/1118151239173328896 Lars Marius Garshol. Twitter feed. 04/16/2019.]</ref>) or kveikstokk through the krausen of a fermenting beer, and then hang the ring/kveikstokk to dry. On the next batch, the ring/kveikstokk is dunked into wort to reactivate the yeast <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/1505143962847146/?comment_id=1505145579513651&reply_comment_id=1505163232845219&comment_tracking=%7B%22tn%22%3A%22R%22%7D Lars Marius garshol. Milk The Funk Facebook group post about using a kveik ring. 2017.]</ref>. Note that not all yeast reacts well to drying. Kveik has this exceptional ability. For example, ''Brettanomyces'' is known to not be tolerant of drying/desiccation <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/2237938229567712/?comment_id=2237959286232273&comment_tracking=%7B%22tn%22%3A%22R%22%7D Justin Amaral. Milk The Funk Facebook group post on kveikstokk and drying ''Brettanomyces''. 08/16/2018.]</ref>.
Dried kveik should be stored in the freezer, and has been known to last at least be recoverable after 20 years when stored in this way. While recovery of very old dried kveik may be possible using microbiological techniques, very old dried kveik might not be viable enough for brewers to revive using simple starter techniques. [http://suigenerisbrewing.com/index.php/2019/08/28/drying-kveik-the-grand-finale Microbiolgist Dr. Bryan Heit measured the viability of kveik] that was dried using a dehydrator and stored in a home freezer, and found that viability decreased by about 6-8% per month. Dr. Heit estimated (and then later confirmed via cell counts) that at 6 months, the kveik would be at about 50% viability, which is good enough to pitch directly into wort without a starter. Therefore, if the kveik has been frozen for 6 months or less, dried kveik can be thawed and simply added to a liter or so of ~30°C (86°F) wort for 2-4 hours before adding that to the main batch of wort. If the dried kveik is older than 6 months, a starter is recommended . Dr. Heit used Voss kveik for his experiment, and included some limitations such as sample size, using kveik from a yeast cake instead of using fresher yeast from top cropping or a starter, using a yeast cake with a high hop content (while hps are not toxic to yeast, a high content of hops could further stress the yeast), using a dehydrator that had high and fluctuating tmperatures intead of a better quality dehydrator (Dr. Heit recommends drying at 35-40°C), and probable under-estimates of viability due to using trypan blue dye, which is known to stain both dead cells and cells that are alive but are undergoing cell division <ref name="garshol_preiss_mbaa" /><ref>[http://suigenerisbrewing.com/index.php/2019/08/28/drying-kveik-the-grand-finale Dr. Bryan Heit. Sui Generis Blog post about dried kveik viability over time. 0408/2528/2019.]</ref>.
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