I really like it too, but I brewed a maibock today using S-189: a really good yeast if you can find it.
What’s interesting about W-34/70 is that it is not a strain. It’s the 70th isolate of strain number 34. Hefebank Weihenstephan also offers W-34/78.
What’s an isolate you may ask? Well, it’s a single well-isolated colony from a plate.
The yeast culture in the photo shown below is from Scottish and Newcastle’s Tyne Brewery. The well isolated round colonies in the lower right-hand quadrant of the plate are isolates because each one was formed by the offspring of single yeast cell. Yeast cells can undergo mutation in use. Periodic isolate selection can lead to the selection of cultures that have slightly or radically different performance characteristics.
So unless we have lab rated instruments, and do lab level isolations, we cannot know with a reasonable degree of certainty that the yeast we repitch will achieve the same results as the lab produced specimen of that yeast, right?
But as a homebrewer can we accept the clean resulting yeast of an initial pitch with a fair degree of certainty to produce a similar beer?
I love science 
This is to be released by Fermentis in 11.5 g sachets this year…
Mark, or anyone else, do you have background on the origin of S-189?
All yeast cultures drift over time. That’s why labs store important master cultures at -196C. At that temperature, life goes into suspended animation.
I would argue that each of the BRY 96 descendents (i.e., “Chico,” Wyeast 1056, WLP001, and US-05) are slightly different because they are isolates.
In my humble opinion, home brewers should embrace drift, that is, as long as the drift is not affecting the finished product negatively. Drift is how one develops a “house” yeast strain. For example, there’s zero doubt in my mind that the yeast strains used by Young’s and Fuller’s strain share a common ancestor.
I believe that the strain originates from the Hürlimann Brewery.
Yeah, that’s what I’ve found also.
If I ever do a 14% lager I will use this yeast. 
Sounds like an excellent strain for Baltic Porter then
Although I’ve made some great maibock with it at a lot less than 14%!
Good to hear, I did a 1.070 maibock yesterday that should come out to a little over half that.
I’m good with that.