Saflager W-34/70

[YeastWhisperer]

W-34/70 can ferment as high as 22C without producing much in the way of off-flavors. W-34/70 belongs to family of lager yeast (Saccharomyces pastorianus or S. pastorianus) strains known as the Frohberg family. Up until last year, it was believed that Frohberg lager strains were triploids with two sets of Saccharomyces cerevisiae (S. cerevisiae) chromosomes and one set of Saccharomyces eubayanus (S. eubayanus) chromosomes. However, genetic research performed at Carlsberg Laboratory revealed that the members of the Frohberg lager yeast family are actually tetraploids that contain two sets of S. cerevisiae chromosomes and two sets of S. eubayanus chromosomes.

Many home brewers erroneously believe that they have to ferment lager at 5-10C. However, Frohberg strains perform better at 15C than they do at 10C due to being half ale yeast (S. Cerevisiae). Almost all modern production larger strains are Frohberg strains that are used at 15C. Many of these strains descend from Weihenstephan strain number 34 (W-34/70 is an isolate of strain number 34). Fermenting with a Frohberg strain at 15C greatly reduces to outright eliminates the need to perform a diacetyl rest.

The strains that benefit from truly cold fermentation belong the Saaz family of lager yeast strains. Saaz strains are triploids with one set of S. cerevisiae chromosomes and two sets of S. eubayanus chromosomes. S. eubayanus is the parent that contributed the cold tolerance genes. Most historical German yeast strains are Frohberg strains whereas most historical Czech and Danish yeast are Saaz strains. This information is just a little food for thought.

[j444fog]

[quote="beerlover36"]I've used 34/70 for a few lager brews over the winter and it's been excellent. I fermented at around 13/14 C and got down to FG in a week on each occasion, that may seem a little warm but the instructions say 12-15C, and there was absolutely no off-flavours. The only other time I've brewed lager I used Wyeast Urquell which was good but took over 2 weeks and a rise to room temperature to finish off. I'll definitely be using 34/70 again, it's great to find a decent yeast in dried format[/quote]

Did you pitch the 34/70 dry or did you re-hydrate and then pitch?