Yeast viability tests for highly flocculent strains

[benn_ross]

Hello,
I use WLP007 as a house yeast. I like how how bright the beer gets as well as the ester profile. I have been having trouble however is with viability counts.

As it is highly flocculent, I have been using food grade phosphoric acid in my dilution water to break up the floccs at a concentration of 1:100 (75% phos acid : water). However it seems to be affecting the methylene blue stain, making it almost impossible to discern viability.

I have tried varying concentrations of acid, as well as methylene blue with little success.

I'm curious, has anyone else run into this issue?

[jbell71464]

We also use WLP007 as one of our workhorse strains. One thing we do is we preload our 1/2bbl modified keg brinks with 5 gallons of distilled water the night before and chill overnight. This has helped put the yeast dormant more quickly and also thins out the slurry allowing a second settling giving us better viability numbers.

[mobcraftbeer]

Wlp007

We used to use WLP007 as our house strain and we also had a lot of difficulty determining viability both at harvest and prior to pitching with methylene blue, i beleive there are a few other stains that may work as well but i can't remember any of thier names right now. We just switched back to US-05 (so far only percievable difference is longer D-rest and less esters), it is like night and day when doing yeast counts for that yeast.

[UnFermentable]

I would suggest you try using EDTA to break up clumpy strains.

[TheKevin]

Viability

I have stopped using Methylene Blue almost altogether and started using Trypan blue. I noticed that using an acid to break up flocculation affects the uptake of M.blue. Trypan blue is much more accurate (a little more pricey), but takes into account cell wall integrity as it pertains to healthy cells. This should help a ton. I typically use a 100 dilution factor with 0.8% Trypan Blue solution and it works great.