Landrace Yeast

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Although landrace is a term used in many areas, this page will be using it as descriptors of a yeast or mixed culture that derives from a traditional farmhouse/landrace brewing cultures from around the world. This term was first used to describe yeast by Tyrawa et al. (2018) to describe traditional Norwegian kveik yeast [1], and to distinguish them from Saison yeast, which are also sometimes referred to as "farmhouse yeast" [2]. The exact definition of the word "landrace" is debated in the Plant Sciences, and is therefore outside the scope of this wiki [3].

The term "landrace" should not be confused with "kveik" as the former is a term used specifically for Norwegian farmhouse brewing yeast and mixed cultures, which could be classified as a subgroup of "landrace yeasts" or "landrace cultures".

More information on Norwegian kveik can be found on the Kveik page.

Cultures

Until the introduction of Emil Chr. Hansen's pure-yeast system in 1883, all yeast was treated in effectively the same way as kveik. However, pure lab yeast generally replaced the ancient cultures all over the world. In farmhouse brewing, the old practices continued until quite recently in several Nordic and Baltic countries. Farmhouse brewing still continues in Denmark, Finland, Sweden, Estonia, Latvia, and Lithuania. As far as is known, Lithuania is the only country other than Norway in which the old yeast cultures are still alive, and used in the same way as they were in the past. See Lithuanian beer - a rough guide for more information. Genetically speaking, these yeast cultures are generally not in the same family as kveik, and thus are not referred to as "kveik". The alternative nomenclature of "Landrace yeast" has been suggested by Richard Preiss.

Below are the listed known Farmhouse cultures and information we've been able to compile on them.


Simonaitis

One yeast has been collected from farmhouse brewer Julius Simonaitis in Joniškelis, Lithuania. It's a communal yeast that's been shared with the neighbors since time immemorial. NCYC says the yeast consists of 5 different strains of S. cerevisiae [4]. Four of these are closely related, while the fifth is quite different, and is probably a completely different strain. All seem to be Saccharomyces cerevisiae. Technically, this culture is not considered to be "kveik" because it genetically falls outside of the kveik families and because it is POF+ (phenolic producing) [5][6].

Julius pitches the yeast at 35C and top-harvests it. He ferments 12-16 hours, depending on activity.

People trading this culture have reported that there are lactic acid bacteria present in the culture. It is not known if this lactic acid bacteria was present from the source, or if it was introduced during trading. Julius Simonaitis's beers are reported to not be sour, but he uses a lot of hops in his beer and his beer is reportedly fairly bitter. DeWayne Schaaf reported that the lactic acid bacteria present in the culture he was given produced a favorable acidity. Lars Garshol is waiting on lab results to see if the lactic acid bacteria were present in the original culture [7].

Commercially available from Mainiacal Yeast Labs (contains lactic acid bacteria). Also available from Sleight Beer Lab.

Jovaru Alus

This is another Lithuanian strain from the Jovaru Alus brewery in the small community of Jovarai. The brewer, Aldona Udriene, discusses the history of this true farmhouse brewery in this article. She expressed in the article that she was reluctant to give up the yeast, but Omega Yeast Labs reached an agreement with her to bank the culture and offer it for sale as the product OYL-033. Omega Yeast Labs describes the yeast as, "citrusy esters and restrained phenols..." and having the, "character of lemon pith, black pepper, and a soft mouthfeel." The Omega Yeast Labs culture is a single isolate, and Lance Shaner says that there was no evidence of more than one strain of S. cerevisiae in the culture that they recieved, although there was a Lactobacillus contamination which they removed from the commercially offered Omega Yeast Labs product [8].

(Fast forward to 19:40):

Rima

Two strains of landrace farmhouse yeast cultures from Russia were analyzed by Richard Preiss of Escarpment Laboratories referred to by the family names "Rima" and "Marina" (see this tweet and this tweet by Lars Marius Garshol pending a write up by Lars). The lab performed ITS sequencing, PCR fingerprinting, and mini 7 day ferments with these strains. Unlike kveik, all of the S. cerevisiae strains were POF+ (phenol producers).

According to the PCR fingerprinting, Rima contained at least two strains of S. cerevisiae but maybe more, as well as a strain of Pichia kudriavzevii (a fairly common beer contaminant). The first strain of S. cerevisiae was described as "fruity, relatively clean, and fermented similar to WLP001". The second strain of S. cerevisiae produced high amounts of diacetyl and under attenuated. The Pichia was described as "pretty gross and didn't attenuate much".

Marina

Marina contained what appears to be three closely related S. cerevisiae strains. They all showed pretty low attenuation after one week, but subsequent fermentations can be carried out longer. The flavors were described as "pretty neutral". There is a fourth yeast strain in the Marina that has yet to be identified [9].

Bjarne Muri's Olden Farmhouse Yeast

"Muri is an interspecies hybrid between S. cerevisiae and S. uvarum. Hybrids of this combination have previously been isolated from wine fermentations, but there are limited reports of any from brewing environments. S. uvarum is closely related to S. eubayanus, one of the parents of lager yeast (which is also a hybrid).

Phylogenetic analysis of the two parental genomes of Muri revealed that the S. cerevisiae parent appears to belong to the Beer2 group, and is most closely related to various English ale strains. The parent strain was therefore not related to any of the other (sequenced) kveik isolates. It is not included in the paper, but Muri is also different to e.g. the S6U S. cerevisiae × S. uvarum hybrid that was isolated from wine, where the S. cerevisiae parent groups in the Wine clade. The S. uvarum parent was most closely related to Central European S. uvarum strains used for cider making (unfortunately S. uvarum strains haven't been sequenced as much as S. cerevisiae strains).

The S. uvarum genome of Muri also contains a lot of introgressions from S. eubayanus. This is common in domesticated S. uvarum strains. Muri, for example, appears to have a chimeric chromosome 7, where half is from S. uvarum and half from S. eubayanus.

We then obtained some of the closely related S. cerevisiae and S. uvarum strains, as well as some other hybrids, and compared their phenotypic properties (with focus on those related to brewing).

Muri is POF+, diastatic (STA+), has a wide temperature range of growth, good flocculation and good ethanol tolerance.

The S. cerevisiae and S. uvarum strains that were genetically most similar to Muri also were the most similar phenotypically. These are named A241 and C995 in the paper, respectively.

We then attempted to recreate the Muri hybrid by creating new hybrids between A241 and C995.

We then compared the newly created hybrids with Muri, and found that the new hybrids were more similar to Muri than either of the parent strains. However, they still differed in some respects (e.g. low temperature wort fermentations). There are several potential reasons for this, e.g. the heterozygosity of the parent strains, the sequence divergence between Muri and the parent strains, the effect of the S. eubayanus introgressions, and the mitochondrial inheritance.

This approach of creating new hybrids that mimic an existing one might not be very valuable for the average brewer, but it is something that could be useful in researching how yeast hybrids adapt and change. For example, one could try to recontruct lager yeast in a similar fashion, and see what kind of conditions give rise to similar genetic changes that have occured in the lager yeast during the hundreds of years the hybrids have existed.

So to sum up, Muri is a hybrid and is not related to other kveik strains (there is the possibility of contamination when Bjarne tried to revive his kveik culture, but the strain is nevertheless interesting and unique). The S. cerevisiae x S. uvarum combination is rare in brewing. Muri is POF+ and diastatic, so might work well for saisons or other beer styles where 4VG and a dry finish is desired." ~ Kristoffer Krogerus summary of his published study [10], A Unique Saccharomyces cerevisiae × Saccharomyces uvarum Hybrid Isolated From Norwegian Farmhouse Beer: Characterization and Reconstruction.

See Also

Additional Articles on MTF Wiki

External Resources

References