WLP740 Merlot Red Wine Yeast - Diastatic Wine Yeast?

[RBinson]

Hello everyone,

I wanted to know if anyone has experience with the WLP740? It's the first time I see about a supposedly diastatic wine yeast. I know the STA1 is more a precondition than a real indicator of a diastatic yeast, so I was wondering if it really produces amylase.

Moreover, does anyone knows if it's a killer yeast? It seems like most red wine yeasts are killer yeasts but I cannot find information about that on White Labs website.

 

[suregork]

Never tried it, but one of the White Labs wine strains included in this study (Domestication and Divergence of Saccharomyces cerevisiae Beer Yeasts - PubMed) contains the STA1 gene (A deletion in the STA1 promoter determines maltotriose and starch utilization in STA1+ Saccharomyces cerevisiae strains). The strain is wine019, and groups with the Beer 2 / Saison strains. Phenotypically seems close to WLP570. So WLP740 is likely a brewing strain (or has at some point pre-isolation been unintentionally crossbred with a brewing strain).

 

[NTexBrewer]

I would contact White Labs. Have you checked any of the other red wine yeast stains from White Labs? If they list other strains as killer then maybe you can assume that 740 is not.

 

[RBinson]

Never tried it, but one of the White Labs wine strains included in this study (Domestication and Divergence of Saccharomyces cerevisiae Beer Yeasts - PubMed) contains the STA1 gene (A deletion in the STA1 promoter determines maltotriose and starch utilization in STA1+ Saccharomyces cerevisiae strains). The strain is wine019, and groups with the Beer 2 / Saison strains. Phenotypically seems close to WLP570. So WLP740 is likely a brewing strain (or has at some point pre-isolation been unintentionally crossbred with a brewing strain).

Thanks for the info, I took a quick look in the paper and the place of the yeast is indeed intriguing for a wine yeast. I guess I will order one of this day to test it. By-the-way how do you know wine019 is WLP0740? I found it in the dataset but the origin is not indicated (Microbe sample from Saccharomyces cerevisiae - BioSample - NCBI).

I would contact White Labs. Have you checked any of the other red wine yeast stains from White Labs? If they list other strains as killer then maybe you can assume that 740 is not.

I will drop them a message. They don't seem to indicate anything about killer strains in any of their wine strain.

 

[RBinson]

Some updates:

I asked White Labs about the yeast being diastatic, fermenting maltose & maltotriose and the kill factor. At first they just answered me with the copied/pasted paragraph of STA1 being a potential indicator of diastaticus blablabla...

I asked again and they confirmed that the yeast can ferment maltose and maltotriose. They also stated that none of their yeast has the kill factor.

I ordered a vial and I will try to brew a simple Belgian Golden Ale with it.

 

[RBinson]

Reviving the thread after quite some time. I finally brewed a Belgian Golden Strong Ale with the WLP740 yeast (made a starter). In terms of flavor and aroma this is pretty much a Duval clone. Very phenolic and close to what I expected from the style. It was just a beer for testing this yeast but I actually brewed one of my best.

Concerning the diastatic aspect: I did a 60min mash at 67°C with only pilsner malt and I added for 10% of dextrose in the wort. The gravity went from 1.075 to 1.003 after fermenting for 2 weeks at around 24-26°C (in hindsight, a tad too hot) . I will see after a few more weeks how the gravity evolves but seems to have plateaued for now.