Repitching Dry Yeast - S04

[Rosie]

Hey Guys,

I know this is probably not recommended by the manufacturer, but hey it seems like such a waste of yeast...

I've been repitching Fermentis S04 with some good results, pushing the envelope on the number of generations, perhaps. I would be interested in what you think of my observations...

For the first 3 generations, I get consistant fermentation activity, attenuation, flocculation. From the 4th generation, I'm getting beers that don't drop clear any more - as it seems to loose the highly flocculant characteristic of this yeast.

Now, I'm making an assumption that the haze in the beer is yeast, and will employ a couple techniques in recent posts to try and verify. Although, I'm pretty sure it's yeast...previous batches have clumps in bottom of conditioning, where as late generation batches are very powdery.

Another observation I made was in actually tasting the yeast slurry from a 5th generation versus a 2nd. The 5th generation smelled and tasted similar to the 2nd other than an extreme bitterness in the 5th generation. Is it possilbe that I could be carrying over hop compounds into later batches that are causing haze? Is this bitterness from contamination?

Keep in mind that my repitches are pretty primitive....being as sterile as possible, but taking a random bit of slurry, as I do not have a way to collect specific parts of the yeast cake.

Any thoughts or experiences appreciated.

Thanks,

[damoller]

Reusing Dries yeast

I have also reused dry yeast but for only 2 generations! Are you aerating your wort well with the dried yeast? I know the company claims you don't need to and you don't need to but performance and flavor profile improve if you do! Are you collecting your yeast from the bottom of the fermenter of from the surface?

[Rosie]

Doug,

Yes, aerating as normal...same for all batches. Repitching from slurry collected at bottom of fermenter.

Cheers,

Jeff

[gitchegumee]

I've repitched this yeast for 4-5 generations without any problems, but would not repitch any yeast if it couldn't be done with a good cylindroconical tank. The trub and reduced yeast vitality would surely catch up to you quickly. It's not a waste of yeast if it's not up to your standards. Good luck!

[Brew Chef]

I repitch this yeast often as well. I do notice some variation in flocculation and I'm curious if the generations has something to do with it as mentioned. This yeast performs very well for our brewery though....fresh or repitched.

[JoeV]

Why not?

You can re-pitch dry yeast. It isn't any different from slurry yeast. You will not get the same results consitently because of the limitations of re-pitching. Every time you re-pitch any defects with the slurry are multiplied. So if there is any bacteria it increases each pitch (barring acid washing). Any "mutations" can also be multiplied. So if you are re-pitching and want to ensure consistency you should pull yeast from the middle of the cone, the bottom is dead yeast and trub, the top is less flocculant yeast. You could also do bacterial cell counts, TCC overlay for respiratory deficient mutants and flocculation test, attenuation tests and so on before each pitch. OR you could just pay the dry yeast maker to handle all this quality control for you and start with fresh yeast each time.

[pennbrew2]

If you're not adding zinc to your wort, it's likely your yeast is becoming zinc deficient. Add Zinc Sulfate (heptahydrate is the most common and cheapest form) at the rate of 0.5 ppm Zn to the kettle 10 minutes before knockout.

---Guy

[Sir Brewsalot]

We repitch this yeast a LOT.

Not sure offhand how many generations we've gone up to, but it's been more than 10 at some point.

Getting a successful floc out of subsequent pitches is all about how you harvest from the source tank. Dump the first bit that's bitter and trub-filled, then SLOWLY pull the middle layer. If you go fast, it will "rat-hole" and you'll wind up with a larger population of lo-floc, geriatric types... more with each repitch as the generations grow.

Slow and steady. If it's taking 5 minutes to pull 5 gal of it, you may be going too fast.
Cheers,
Scott

[Guest]

We're repitching S04 a few gens at the minute, but a chance chat with someone from a UK brewing school (that you're familiar with, Jeff) led us to now also initially pitch with a greatly reduced quantity of dried yeast than is recommended by the manufacturer - I think we're down to 250g in a 10UK-Bbl brew (14US-Bbl/16.4Hl). The recommended pitching rate is 50-80g/Hl i.e. 820-1312g for my brewlength.

Just curious - how much good slurry are people pitching with?
cheers
Mike

[Sir Brewsalot]

I also find this yeast in it's dry form to be rather potent. Repitches are on par with other yeasts though, quantity wise.
Cheers,
Scott