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Kveik

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At one time kveik was the only available form of yeast in Norway (and, of course, similar methods for reusing yeast were used all over the world prior to Emil Chr. Hansen's introduction of the pure-yeast system in 1883). However, the existence of kveik has mostly disappeared in recent times. Today kveik remains in the districts of Hardanger, Voss, Sogn, Nordfjord, and Sunnmøre, at least. Kveik is only used by homebrewers who still brew in the traditional methods of Norwegian farmhouse brewing, although the recent spreading of kveik throughout the world has led to a resurgence in its usage to make various types of beer, including non-farmhouse style beers <ref name="larsblog_norwegian_farmhouse">[http://www.garshol.priv.no/blog/259.html Norwegian farmhouse ale. Larsblog. 10/27/2013. Retrieved 01/14/2016.]</ref>.
=Thanks to efforts by Lars Marius Garshol and Håken Hveem, and Norwegian farmhouse brewers Svein Rivenes, Sigmund Gjernes, Bjarne Muri, Terje Raftevold, and others, kveik has been made commercially available to brewers around the world. Much of the analysis has been performed by the [http://www.ncyc.co.uk National Collection of Yeast Cultures (NCYC)] and [[Escarpment Laboratories]]. See also the [http://www.garshol.priv.no/download/farmhouse/kveik.html Kveik Registry] being maintained by Lars Marius Garshol. ===Terminology====
* "Kveik" is not a beer style. Its translated meaning is "yeast". For more information, see Lars Marius Garshol's blog post [http://www.garshol.priv.no/blog/380.html "What Does 'Kveik' Mean?"].
* If you do use kveik in a commercial beer, please consider giving the name of the original owner of the kveik on the label. This gives credit to the brewers who have donated their family heritage to the brewers of the world, and it is also helpful for those who want to know exactly which yeast was used in the beer. If you are uncertain about the name of the owner, consult the [http://www.garshol.priv.no/download/farmhouse/kveik.html kveik registry] <ref name="garshol_preiss_mbaa" /><ref>[https://www.facebook.com/groups/592560317438853?view=permalink&id=2484869138207952 Varying opinions from MTF members, including Norwegians. Milk The Funk Facebook group chat about putting 'kveik' and where it is from on beer labels for mixed fermentation sour beers. 01/28/2019.]</ref>.
* Since the word 'kveik" refers only to Norwegian yeasts, and there are farmhouse yeasts in other countries, the term "landrace yeast" has been proposed to refer to all farmhouse-domesticated yeast. See also [[Landrace Yeast]] and [https://www.facebook.com/groups/MilkTheFunk/permalink/2389386811089519/ this MTF thread discussing the usage of the word "landrace" for these farmhouse yeasts].
* [https://www.facebook.com/groups/kveik/permalink/1857521244303344/ Thread in the Kveik Facebook group on why lab isolated strains are still considered "kveik".] It is useful to distinguish between purified single-strain kveik, purified multi-strain kveik, and unpurified original culture <ref>[https://www.facebook.com/groups/kveik/permalink/1857521244303344/ Lars Marius Garshol. Kveik facebook group thread on kveik terminology. 11/03/2018.]</ref>.
 
==Yeast Lab Analysis==
[[File:Kveik microscope.jpg|thumbnail|right|The dried kveik samples (Stordal) showed much better viability/cell health (less granulated/wrinkly appearance) than the liquid samples (eg Hornidal). However, some of the liquid samples were pretty healthy too (Voss). Source [https://www.facebook.com/photo.php?fbid=10205280742451727&set=gm.1336954522999425&type=3&permPage=1&ifg=1 Richard Preiss of Escarpment Labs].]]
 
Analysis has also been performed at the Norwegian University of Science and Technology (NTNU) by [https://brage.bibsys.no/xmlui/handle/11250/2390204 Truls C Rasmussen], as well as [[Escarpment Laboratories]].
* [https://www.facebook.com/groups/MilkTheFunk/permalink/1398200433541500/?comment_id=1398379970190213&comment_tracking=%7B%22tn%22%3A%22R%22%7D MTF feedback on the NTNU analysis.]
* [https://www.facebook.com/groups/MilkTheFunk/permalink/2277955402232661/ Updates to the Escarpment Laboratories (Preiss et al.) analysis on MTF.] and their published paper [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"].
 
In general, most of the cultures of kveik that have been analyzed contain more than one strain of ''S. cerevisiae''. The exact number of strains that is present in a given kveik culture is difficult to analyze; generally labs with better equipment and more time can identify more strains than others. Some kveik cultures contain multiple strains of closely related strains of ''S. cerevisiae'', while others contain a more diverse group of strains <ref name="garshol_preiss_mbaa" />. The kveik cultures with closely related strains defy what a "strain" isolate is; Richard Preiss describes these kveik cultures as being "heterogenous but related communities", meaning that there can be a lot of genetic overlap between subpopulations in a kveik culture and where one strain begins and another ends is not possible to define <ref name="preiss_strains" />. ''S. cerevisiae'' was the only species in all of the kveik cultures analyzed by Preiss et al. (2018), except for the Muri kveik. The Muri kveik contains a single isolate of what appears to be a domestic (human produced) hybrid between ''S. cerevisiae'', ''S. eubayanus'', and ''S. uvarum''. Of the 9 kveik cultures analyzed by Preiss et al. (2018), only Muri, Simonaitis, and Stranda contained only one strain of ''S. cerevisiae'', while all of the others contained more than one strain of ''S. cerevisiae'' up to 9 strains in the case of Granvin (see [https://www.frontiersin.org/files/Articles/409253/fmicb-09-02137-HTML-r1/image_m/fmicb-09-02137-t001.jpg this table from the paper]). Genetically, kveik yeast strains form their own group of closely related domesticated ale strains that are a subgroup of the "Beer 1" yeasts (Belgian/Germany/UK/US yeast strains) from the [http://www.cell.com/cell/fulltext/S0092-8674(16)31071-6 Gillons/White Labs (2016)] study that sequenced previously known ale strains and found them to make up two genetically related groups called "Beer 1" and "Beer 2" (see [[Saccharomyces#History_of_Domestication|''Saccharomyces'' History of Domestication]] and [http://www.garshol.priv.no/blog/374.html "A family tree for brewer's yeast" by Lars Marius Garshol]). The closest related domesticated strains were 3 German hefeweizen strains, however, this relation is likely just due to both groups being hybrids rather than having any historic relation <ref name="Tyrawa_2017" />. None of the kveik strains sequenced by Preiss et al. (2018) contained the STA1 gene for diastaticus, which is expected since all of the diastaticus yeasts belong to the "Beer 2" group <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/2445690998792433/?comment_id=2446266075401592&reply_comment_id=2446269382067928&comment_tracking=%7B%22tn%22%3A%22R5%22%7D Richard Preiss. Milk The Funk Facebook thread on kveik and the STA1 gene. 01/03/2018.]</ref>.
 
Although whole genome sequencing of more kveik strains is needed in order to fully flesh out a family tree of kveik <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/2277955402232661/?comment_id=2279696338725234&reply_comment_id=2279736462054555&comment_tracking=%7B%22tn%22%3A%22R%2321%22%7D Richard Preiss. Milk The Funk Facebook group comment about the two families of kveik yeast. 09/13/2018.]</ref>, based on the 6 strains that were analyzed, kveik strains seem to be divided into two related genetic groups, with the Muri, the Simonatis Lithuanian strain, and a Norwegian bread yeast falling outside of these two groups completely, which arguably categorizes them to not actually be considered "kveik". The two groups of kveik probably originated from two ancestors that were hybrids between a "Beer 1" yeast and wild yeast. Interestingly, the kveik cultures that have multiple strains have strains from both genetic groups of kveik. For example, Hornindal, Granvin, Laerdal, and Stordal Ebbergarden all contained strains from both genetic groups of kveik. Overall, their genetic diversity is wider than the genetic diversity of other "Beer 1" subgroups <ref name="Tyrawa_2017" />. See this [https://www.frontiersin.org/files/Articles/409253/fmicb-09-02137-HTML-r1/image_m/fmicb-09-02137-g002.jpg updated family diagram of yeast].
 
Preiss et al. (2018) also measured the fermentation characteristics of individual kveik strains in their study, the first published data in this regard for kveik. At 86°F (30°C) they found that 11 of the 24 pure strains of kveik outperformed the best control strain (WLP002) in fermentation rate. There was still a very wide range of attenuation rates between the kveik strains (60-90%). Of the 6 strains that had their DNA sequenced, all but one of the Granvin strains fermented maltotriose. All of the strains tested were POF- (meaning they did not produce significant 4-vinylguaiacol phenol) except the Muri strain which is not genetically related to kveik. One of these Stordal Ebbegarden strains also contained a unique mutation on the ''FDC1'' gene that results in the inability to produce phenols and has not been reported before in science. They also found that kveik strains tend to produce fatty acid esters at levels that are typical for other domesticated yeast strains, such as ethyl caproate (pineapple, tropical; threshold 0.21 ppm), ethyl caprylate (tropical, apple, cognac; threshold 0.9 ppm), and ethyl decanoate (apple; threshold 0.2 ppm). The kveik strains studied did not produce high levels of the isoamyl acetate ester (banana) and generally lower levels of the fusel alcohol isobutanol compared WLP001 and WLP002. Strangely, 5 of the 6 strains that were analyzed could form spores, which is not typical for brewers yeast <ref name="Tyrawa_2017" />.
 
The kveik strains studied by Preiss et al. (2018) displayed unique abilities as far as withstanding stress in their environment. Most of the strains at least doubled their growth at 43°C and grew to their maximum potential at 40°C, while the control strains WLP001, WLP002, and WLP029 showed limited growth at those temperatures. This demonstrates kveik's ability to withstand high-temperature fermentations. All strains tested died at 45°C <ref name="Tyrawa_2017" />.
 
Kveik strains were also demonstrated by Preiss et al. (2018) to have a higher tolerance to alcohol than some of the domesticated strains tested (WLP001, WLP002, and WLP029), as well as unique flocculation characteristics. Most of the kveik strains doubled in growth in media with 14% ABV ethanol, and about half of them doubled in growth in 16% ABV ethanol media. Half of the strains of kveik were highly flocculant, but some other strains were very poor flocculators. It is possible that since kveik is a mixed culture of several strains of yeast that the highly flocculant strains assist the others in flocculation thus diminishing for the other strains to evolve flocculation properties <ref name="Tyrawa_2017" />.
 
See also:
* [http://www.garshol.priv.no/blog/391.html "Where kveik comes from", an analysis of the Preiss et al. study by Lars Marius Garshol.]
* [https://www.facebook.com/groups/MilkTheFunk/permalink/2277955402232661/ MTF thread post by Richard Preiss summarizing the study's findings.]
===Sensory and Fermentation Profile===
There are farmhouse yeasts in other countries that have survived for generations, similar to kveik, but are genetically distinct from kveik. Since the term "kveik" refers to just Norwegian farmhouse yeast, the term "landrace yeast" has been proposed to refer to farmhouse yeasts as a category of yeast. Non-kveik landrace yeast includes yeasts from Lithuania and Russia include Simonaitis, Rima, and Jovaru Alus. See [[Landrace Yeast]] for more information and commercially available cultures.
==Yeast Lab Analysis and Strain Specific Kveik Culture Information==[[File:Kveik microscope.jpg|thumbnail|right|The dried kveik samples (Stordal) showed much better viability/cell health (less granulated/wrinkly appearance) than the liquid samples (eg Hornidal). However, some of the liquid samples were pretty healthy too (Voss). Source [https://www.facebook.com/photo.php?fbid=10205280742451727&set=gm.1336954522999425&type=3&permPage=1&ifg=1 Richard Preiss of Escarpment Labs].]] Thanks to efforts by Lars Marius Garshol and Håken Hveem, and Norwegian farmhouse brewers Svein Rivenes, Sigmund Gjernes, Bjarne Muri, Terje Raftevold, and others, kveik has been made commercially available to brewers around the world. Much of the analysis has been performed by the [http://www.ncyc.co.uk National Collection of Yeast Cultures (NCYC)] and [[Escarpment Laboratories]]. See also the [http://www.garshol.priv.no/download/farmhouse/kveik.html Kveik Farmhouse Yeast Registry] being maintained by Lars Marius Garshol. Analysis has also been performed at the Norwegian University of Science and Technology (NTNU) by [https://brage.bibsys.no/xmlui/handle/11250/2390204 Truls C Rasmussen], as well as [[Escarpment Laboratories]]. * [https://www.facebook.com/groups/MilkTheFunk/permalink/1398200433541500/?comment_id=1398379970190213&comment_tracking=%7B%22tn%22%3A%22R%22%7D MTF feedback on the NTNU analysis.] * [https://www.facebook.com/groups/MilkTheFunk/permalink/2277955402232661/ Updates to the Escarpment Laboratories (Preiss et al.) analysis on MTF.] and their published paper [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"].  In general, most of the cultures of kveik that have been analyzed contain more than one strain of ''S. cerevisiae''. The exact number of strains that is present in a given kveik culture is difficult to analyze; generally labs with better equipment and more time can identify more strains than others. Some kveik cultures contain multiple strains of closely related strains of ''S. cerevisiae'', while others contain a more diverse group of strains <ref name="garshol_preiss_mbaa" />. The kveik cultures with closely related strains defy what a "strain" isolate is; Richard Preiss describes these kveik cultures as being "heterogenous but related communities", meaning that there can be a lot of genetic overlap between subpopulations in a kveik culture and where one strain begins and another ends is not possible to define <ref name="preiss_strains" />. ''S. cerevisiae'' was the only species in all of the kveik cultures analyzed by Preiss et al. (2018), except for the Muri kveik. The Muri kveik contains a single isolate of what appears to be a domestic (human produced) hybrid between ''S. cerevisiae'', ''S. eubayanus'', and ''S. uvarum''. Of the 9 kveik cultures analyzed by Preiss et al. (2018), only Muri, Simonaitis, and Stranda contained only one strain of ''S. cerevisiae'', while all of the others contained more than one strain of ''S. cerevisiae'' up to 9 strains in the case of Granvin (see [https://www.frontiersin.org/files/Articles/409253/fmicb-09-02137-HTML-r1/image_m/fmicb-09-02137-t001.jpg this table from the paper]). Genetically, kveik yeast strains form their own group of closely related domesticated ale strains that are a subgroup of the "Beer 1" yeasts (Belgian/Germany/UK/US yeast strains) from the [http://www.cell.com/cell/fulltext/S0092-8674(16)31071-6 Gillons/White Labs (2016)] study that sequenced previously known ale strains and found them to make up two genetically related groups called "Beer 1" and "Beer 2" (see [[Saccharomyces#History_of_Domestication|''Saccharomyces'' History of Domestication]] and [http://www.garshol.priv.no/blog/374.html "A family tree for brewer's yeast" by Lars Marius Garshol]). The closest related domesticated strains were 3 German hefeweizen strains, however, this relation is likely just due to both groups being hybrids rather than having any historic relation <ref name="Tyrawa_2017" />. None of the kveik strains sequenced by Preiss et al. (2018) contained the STA1 gene for diastaticus, which is expected since all of the diastaticus yeasts belong to the "Beer 2" group <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/2445690998792433/?comment_id=2446266075401592&reply_comment_id=2446269382067928&comment_tracking=%7B%22tn%22%3A%22R5%22%7D Richard Preiss. Milk The Funk Facebook thread updated information on kveik and the STA1 gene. 01/03/2018.]</ref>.  Although whole genome sequencing of more kveik strains is needed in order to fully flesh out a family tree of kveik <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/2277955402232661/?comment_id=2279696338725234&reply_comment_id=2279736462054555&comment_tracking=%7B%22tn%22%3A%22R%2321%22%7D Richard Preiss. Milk The Funk Facebook group comment about the two families of kveik yeast. 09/13/2018.]</ref>, based on the 6 strains that were analyzed, kveik strains seem to be divided into two related genetic groups, with the Muri, the Simonatis Lithuanian strain, and a Norwegian bread yeast falling outside of these two groups completely, which arguably categorizes them to not actually be considered "kveik". The two groups of kveik probably originated from two ancestors that were hybrids between a "Beer 1" yeast and wild yeast. Interestingly, the individual kveik cultures that have multiple strains have strains from both genetic groups of kveik. For example, Hornindal, Granvin, Laerdal, and Stordal Ebbergarden all contained strains from both genetic groups of kveik. Overall, their genetic diversity is wider than the genetic diversity of other "Beer 1" subgroups <ref name="Tyrawa_2017" />. See this [https://www.frontiersin.org/files/Articles/409253/fmicb-09-02137-HTML-r1/image_m/fmicb-09-02137-g002.jpg updated family diagram of yeast]. Preiss et al. (2018) also measured the fermentation characteristics of individual kveik strains in their study, the first published data in this regard for kveik. At 86°F (30°C) they found that 11 of the 24 pure strains of kveik outperformed the best control strain (WLP002) in fermentation rate. There was still a very wide range of attenuation rates between the kveik strains (60-90%). Of the 6 strains that had their DNA sequenced, all but one of the Granvin strains fermented maltotriose. All of the strains tested were POF- (meaning they did not produce significant 4-vinylguaiacol phenol) except the Muri strain which is not genetically related to kveik. One of these Stordal Ebbegarden strains also contained a unique mutation on the ''FDC1'' gene that results in the inability to produce phenols and has not been reported before in science. They also found that kveik strains tend to produce fatty acid esters at levels that are typical for other domesticated yeast strains, such as ethyl caproate (pineapple, tropical; threshold 0.21 ppm), ethyl caprylate (tropical, apple, cognac; threshold 0.9 ppm), and ethyl decanoate (apple; threshold 0.2 ppm). The kveik strains studied did not produce high levels of the isoamyl acetate ester (banana) and generally lower levels of the fusel alcohol isobutanol compared WLP001 and WLP002. Strangely, 5 of the 6 strains that were analyzed could form spores, which is not typical for brewers yeast <ref name="Tyrawa_2017" />. The kveik strains studied by Preiss et al. (2018) displayed unique abilities as far as withstanding stress in their environment. Most of the strains at least doubled their growth at 43°C and grew to their maximum potential at 40°C, while the control strains WLP001, WLP002, and WLP029 showed limited growth at those temperatures. This demonstrates kveik's ability to withstand high-temperature fermentations. All strains tested died at 45°C <ref name="Tyrawa_2017" />.  Kveik strains were also demonstrated by Preiss et al. (2018) to have a higher tolerance to alcohol than some of the domesticated strains tested (WLP001, WLP002, and WLP029), as well as unique flocculation characteristics. Most of the kveik strains doubled in growth in media with 14% ABV ethanol, and about half of them doubled in growth in 16% ABV ethanol media. Half of the strains of kveik were highly flocculant, but some other strains were very poor flocculators. It is possible that since kveik is a mixed culture of several strains of yeast that the highly flocculant strains assist the others in flocculation thus diminishing for the other strains to evolve flocculation properties <ref name="Tyrawa_2017" />.  See also:* [http://www.garshol.priv.no/blog/391.html "Where kveik comes from", an analysis of the Preiss et al. study by Lars Marius Garshol.]* [https://www.facebook.com/groups/MilkTheFunk/permalink/2277955402232661/ MTF thread post by Richard Preiss summarizing the study's findings.]
===Sigmund Gjernes's Voss Kveik===

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