White Labs WLP570 pissing me off

[snowtiger1987]

That is the Belgian Golden Strong if you aren't familiar with the numbers. First, a bit of history. I bought this relatively fresh from the homebrew store (less than a month old), did a small starter (1000ml) and pitched into 5 gallons of Belgian Blonde (OG 1.064) This fermented fine, down to about 1.010 in 7 days. I then recovered the slurry and pitched directly into 5 gallons of Belgian Triple (OG 1.080) This stalled after about 7 days at 1.020 and took some coaxing at 76 degrees to finish at 1.010. I then recovered that slurry and pitched into 10 gallons of Belgian Golden Strong (OG 1.084) and this is where it conked out. It has been 21 days and it won't budge below 1.030 even with raising the temp up to 76 degrees for 7 days.

Instead of "conditioning" the yeast to tolerate higher gravities I think I just wore it out. My plan now to save the beer is to hydrate 2 packs of SA-05 plus 1 pack of champagne yeast and pitch that in hopes that the extra dry yeast nutrients and fresh yeast will finish it out.

 

[corax]

What is a reasonable expectation for the number of re-pitches a given strain can go through? While I would think a run-of-the-mill strain should go more than 3, maybe one cannot expect that from specialized strains?

Is it really standard practice to step up alcohol tolerance by going through full fermentation cycles? Since you're starting with a strain that is advertised as tolerant to begin with, I would naively assume that your best bet would be to start it out in higher alcohol. By starting in lower alcohol, and going through multiple generations, you're relaxing the selective pressure to maintain alcohol tolerance. Perhaps less tolerant variants took over the culture?

 

[Biobrewer]

The ability to repitch definitely will depend on alcohol tolerance and osmo-tolerance. We have a researcher in Brazil looking at some of our Yeast Bay strains, and Wallonian Farmhouse I, Wallonian Farmhouse II, Wallonian Farmhouse III have scored very highly with respect to tolerance of high alcohol and osmotic pressure in lab-based assays. Unsurprising, these are strains that a lot of commercial guys have said they got an insane number of generations out of, same with our Dry Belgian Ale (Belgian Golden Strong Ale style strain).

If you have specific questions regarding WLP570, I would reach out to White Labs and ask. They have a lot of data on strains that might help you out here.

 

[Northern_Brewer]

What is a reasonable expectation for the number of re-pitches a given strain can go through? While I would think a run-of-the-mill strain should go more than 3, maybe one cannot expect that from specialized strains?

I know of British family brewers who are approaching 5000 generations with their own multistrains, and I know people who have taken some commercial strains up to 50 generations or so, but they tend to go a bit weird after 7-12 generations, depending on the strain. High ABVs stress them so they tend to mutate more - it's quite common for abbey brewers to work their yeast up through the ABVs, and then bin them once they've fermented the quadrupel.

Instead of "conditioning" the yeast to tolerate higher gravities I think I just wore it out.

Not so much wore it out, it just couldn't face any more of your crappy conditions. Repitched yeasts have far less food reserves compared to ones straight from the factory, so they will suffer in sub-optimal conditions whereas factory-fresh ones have the reserves to struggle through. Even if your FV is like a desert island for yeast, they can survive if they've come from feasting in the 5* hotel run by Chris White; but move them from one desert island to another and they will have problems.

So look at your aeration and nutrition - it gets harder to rescue a batch once it's started to go wrong, but if nothing else you'll know for next time.

 

[griffi]

I've had great results with 570. I will typically have FG between 1.006 and 1.004 with an OG around 1.070. I like to overbuild a starter and fill an old White Labs tube with 30ml of the decanted starter. I've repitched that multiple times but have probably never done it more than 3 generations. Never had it stall out. It might have more to do with the condition of the yeast slurry at the end of your ferment. Try making a starter closer to 2 liters?
I think pitching s-05 would work to get your ferment unstuck.

 

[snowtiger1987]

Perhaps my strain mutated badly. The Triple is VERY cloudy and slow to drop clear which I have not experienced with this yeast strain before. I pitched the SA-05 and Champagne yeasts last night so I will see how that goes.