Announcing Lutra™ Kveik: A Shockingly Clean Kveik

Lutra™ is a recently-discovered hidden performer within the historic Hornindal blend. It was suspected to be the surprise star of a professional brewer's Helles, brewed with the full Hornindal blend.

Capable of producing a clean canvas, Lutra™ was isolated and analyzed by our brewing scientists.

Less ester-expressive than any other kveik we have encountered, Lutra retains the kveik ability to ferment favorably at very high temperatures relative to other European-origin strains, and therefore with unusual speed:

  • Our tasting panel described a sample Helles brewed with the Lutra™ isolate as clean, crisp, dry, grainy, and “lemony dough."
  • According to a battery of test brews, Lutra maintained an ultra-clean profile when fermented at 68°F - 95°F.
  • For the most lager-like profile, ferment between 68°F - 72°F.
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Lutra is a new Omega Yeast exclusive strain that performs incredibly well in pseudo-lagers, West Coast IPA and American Stout.

At the last Ohio Brewers Conference, a local brewer shared his German-style pilsner with us. Surprisingly, he had used Hornindal, fermented at 70°F. The result of his work was shockingly clean and refreshing -- missing the signature, tropical, fruity complexity that is Hornindal’s usual calling card.

  • Hornindal is known for its outrageous versatility in fermentation temperature, speed, and its complex, modern-hop-complementing fruity esters, which are quite unlike Lutra's clean profile.

We wanted to give the strain capable of fermenting a wildly clean, lager-like canvas the opportunity to work alone.

The lab team systematically isolated Hornindal’s unique strains, looking for the kveik that had until now been talked-over by its more expressive peers, the strain responsible for fermenting a wildly clean, lager-like canvas at kveik temperatures.

Through a series of culture analyses, PhD microbiologist and Director of the Omega Yeast R&D department, Laura Burns, and her team found it, plucked it from its cooperative anonymity, and named it Lutra™ Kveik (OYL-071) after a river otter (a nod to it’s easy going, lovable nature, and to it’s clean, refreshing (river) home).

Less ester-expressive than other kveik, Lutra has proved particularly advantageous in pseudo-lagers, West Coast IPAs and American stouts.


LOOKING FOR LUTRA

How did we isolate Lutra from Hornindal?

We began with a two stage process on Wallerstein Laboratory Nutrient (WLN) Agar. WLN is a handy medium for identifying different strains because it contains a dye (bromocresol green) that is absorbed differently by different strains.

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Some strains accumulate the WLN dye and become dark green. Others don’t, and remain more cream colored.

A colony’s shape and size can also help differentiate the strains. Some exhibit smooth borders while others have rough edges.

Sixteen apparent-unique colonies were observed when differentiating by this combination of color, colony shape or both.


SIXTEEN COLONIES BECOME THIRTEEN ISOLATES

These sixteen unique strains were then re-struck on two additional WLN plates to help verify they are unique isolates.

Three of the sixteen colonies that were struck led to mixed light and dark colonies that indicated that they were not true isolates and were excluded.

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Each potential unique strain is numbered. Capital letters next to the strain number represent colonies presenting as unique by color and/or colony shape. You can see that [1, 9 and 12] and [2, 3 and 11] were categorized as visually identical.

THIRTEEN BECOME NINE

A comparison of the DNA of each strain using interdelta analysis was needed next, to help categorize each strain with another point of comparison.

There are repetitive DNA sequences that can vary in their number and location within the yeast genome. Consequently, when these sequences are amplified by PCR, a band pattern emerges that can vary from strain to strain. The band pattern provides a fingerprint which adds another level of differentiation between strains.

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Interdelta Analysis, band patterns. Notice how the band patterns of strains [2 and 3], [6 and 9] and [1 and 12] are categorized as identical.

USING BAND PATTERNING AND WLN TOGETHER

Strains that had identical band patterns and identical WLN traits were categorized as the same strain.

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Strains 2 and 3 are categorized as the same strain (band pattern “b” and WLN plating “B” = identical band patterns and identical WLN traits)

If two strains had the same band pattern but different WLN appearance, they were categorized as unique strains.

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Strains 6 and 9 are categorized as unique strains (band pattern “c” and WLN plating “E” and “A.” = identical band pattern, different WLN appearance)

Similarly, if two strains had an identical WLN appearance but different band patterns, they were categorized as unique strains.

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Strains 2 and 11 are categorized as unique strains (band patterns “b” and "i", and WLN plating “B” = different band pattern, identical WLN appearance)

This approach allowed us to identify unique strains that may have been assumed to be identical to another strain if a single trait was relied up for differentiation.

As a result, we identified nine (9) unique strains in the Hornindal blend, of which Lutra was one. With test brewing we determined the performance of Lutra as advantageous for pseudo-lagering due to its clean canvas at high temperatures, and likely the strain that stole the show in the Ohio brewers' Helles.