Re-Pitching Dry S-04 and S-05

[StaEva]

For those of you using S-04 and/or S-05 as your main cultures:

How many generations do you typically get from a fresh pitch (presuming you use nutrient each brew and treat the yeast well)? How do they preform when krausened rather than pitching flocculated slurry? I know the cost of dry yeast makes it generally more "expendable" in the eyes of many brewers, but my question is more about the health and performance of these dry strains across many generations—like 6-10+. I've heard a lot of superstitious brewers say they won't use dry yeast for more than 2 gens, but it seems wasteful for no good reason. They're propagating new living cells, exactly the same as slurry yeast.

First-hand accounts are always appreciated!

[CharlosCarlies]

Hopefully someone else can comment, but from what I understand dry yeast manufacturers allow for a very small amount of bacteria/wild yeast in the dehydration process. I'm assuming the reason most people don't re-pitch that many generations is to prevent this from eventually becoming an issue in the beer.

From the US-05 spec sheet:

typical analysis:
% dry weight: 94.0 – 96.5
Viable cells at packaging: > 6 x 109 /g
Total bacteria*: < 5 / ml
Acetic acid bacteria*: < 1 / ml
Lactobacillus*: < 1 / ml
Pediococcus*: < 1 / ml
Wild yeast non Saccharomyces*: < 1 / ml
Pathogenic micro-organisms: in accordance with regulation
*when dry yeast is pitched at 100 g/hl i.e. > 6 x 106
viable cells / ml

FWIW, we usually re-pitch 3-4 generations, but being perfectly honest we aren't setup with the proper QC yet to really see what's going on. Fortunately that will be changing very soon!

[kugeman]

I've seen a drop off in performance after 5 generations with US-05. Not all the time, but enought to be noticeable. Mostly it's poorer than normal attenuation which I have to assume is a drop in viability although I don't have a microscope to stain the yeast and prove it. So I normally pitch about 4 generations depending on the brew schedule.

[dfalken]

I've seen a drop off in performance after 5 generations with US-05. Not all the time, but enought to be noticeable. Mostly it's poorer than normal attenuation which I have to assume is a drop in viability although I don't have a microscope to stain the yeast and prove it. So I normally pitch about 4 generations depending on the brew schedule.

US 05 is the main yeast at our brewery and we regularly pitch it 5 generations but in a pinch have gone up to 6 and haven't had any issues. We are in the process of setting up QC so I can't comment on that level yet but we have been in business for almost 3 years and never have had any issues.

[soia1138]

We have also been repitching US-05 and get 4 to 5 generations out of it. Beyond that we do begin to see a drop in attenuation but that is more due to taking the harvest just post terminal before the dry hop. Naturally over a short period of harvesting the early flocc you will see attenuation issues. I assume if a non dry hopped beer that was harvested post crash we could get more gens from it.

[CharlosCarlies]

We have also been repitching US-05 and get 4 to 5 generations out of it. Beyond that we do begin to see a drop in attenuation but that is more due to taking the harvest just post terminal before the dry hop. Naturally over a short period of harvesting the early flocc you will see attenuation issues. I assume if a non dry hopped beer that was harvested post crash we could get more gens from it.

We were having similar issues, which was frustrating because our best selling beer is a great candidate for pulling yeast but also happens to be dry-hopped.

Have you tried "soft" crashing to 55-60F before pulling yeast? We gave it a try after someone suggested it on here and the results have definitely been positive. The slurry isn't quite as thick as after a full crash, but it's been pretty damn close and still lets us dry-hop on the warmer side.

Just something to try!

[soia1138]

We were having similar issues, which was frustrating because our best selling beer is a great candidate for pulling yeast but also happens to be dry-hopped.

Have you tried "soft" crashing to 55-60F before pulling yeast? We gave it a try after someone suggested it on here and the results have definitely been positive. The slurry isn't quite as thick as after a full crash, but it's been pretty damn close and still lets us dry-hop on the warmer side.

Just something to try!

We do drop to 65F prior to harvest and dry hop at that temp which helps a bit but the main issue really still persists. It's more of a time factor to keep production moving. Once I see terminal gravity for 2 days the tank is capped and temp dropped to 65 then a day later the harvest and first dry hop is done. I won't go any longer, my priority is moving the beer and if a few more generations meant more time on the soft crash then I would rather just pitch fresh and not deal with it honestly.

[beerguy1]

I am using dry yeast for the first time next week I assume most of you just dump it in the ferm on top of well aeriated wort

[wailingguitar]

I am using dry yeast for the first time next week I assume most of you just dump it in the ferm on top of well aeriated wort

I put it in either immediately before xfer or just after xfer has started. I then aerate as normal, this seems to get a quicker start for me. According to Ferments you don't have to aerate the initial pitch (the yeast is processed with lipids for growth apparently), but I saw a substantially slower start if I didn't.

[CharlosCarlies]

We do drop to 65F prior to harvest and dry hop at that temp which helps a bit but the main issue really still persists. It's more of a time factor to keep production moving. Once I see terminal gravity for 2 days the tank is capped and temp dropped to 65 then a day later the harvest and first dry hop is done. I won't go any longer, my priority is moving the beer and if a few more generations meant more time on the soft crash then I would rather just pitch fresh and not deal with it honestly.

That's a good point especially when considering how cheap US-05 is. Just a basic cost/benefit analysis considering tank time.

With that said, have you tried crashing a little colder? We've had decent results at 60F but have considered trying down to 55F. Seems like initiating cooling at all should be enough, but 65F is kinda right smack in the middle of US-05's temp range. Might not matter but just something to try!

[CharlosCarlies]

I put it in either immediately before xfer or just after xfer has started. I then aerate as normal, this seems to get a quicker start for me. According to Ferments you don't have to aerate the initial pitch (the yeast is processed with lipids for growth apparently), but I saw a substantially slower start if I didn't.

Just another data point, but we didn't see any noticeable difference so we don't aerate the first pitch; however, as we're starting to add staff I'm thinking we might just do it anyways to remove the possibility of an absent minded brewer forgetting to aerate the times we do re-pitch or use a liquid strain.

I am using dry yeast for the first time next week I assume most of you just dump it in the ferm on top of well aeriated wort

We actually re-hydrate by sanitizing one of our brinks, filling w/ hot liquor and allowing to cool overnight. We then push the rehydrated yeast in through the racking arm with CO2 while knocking out. Yes it's a little extra work, but I seem to remember someone testing viabilities and re-hydrating in water vs wort did make a noticeable difference. I'd love to be wrong though, so if anyone has any data stating otherwise I'd love to see it!

[StaEva]

Thanks for all the great input!

As a follow up, how is S-04 with diacetyl production in later generations? Anything observable?

[Hop Farmer]

This week is my first time using S-05. We normally use liquid yeast from BSI and get about 10-15 generations out of it. I need a new pitch though and can't get it from BSI in time but I can get S-05 with my normal grain delivery, so I'm giving it a shot. We're running 2 bbl batches and the normal pitching rate seems to be 500 grams per 10 bbls, from what I read. Any recommendations for scaling down to a 2 bbl batch? Starting gravity is around 1.065.

[Bainbridge]

This week is my first time using S-05. We normally use liquid yeast from BSI and get about 10-15 generations out of it. I need a new pitch though and can't get it from BSI in time but I can get S-05 with my normal grain delivery, so I'm giving it a shot. We're running 2 bbl batches and the normal pitching rate seems to be 500 grams per 10 bbls, from what I read. Any recommendations for scaling down to a 2 bbl batch? Starting gravity is around 1.065.

Open 500gm pack.
Weigh out 100gm (or a little more since you're gravity is a little higher) and pitch.
Throw out remainder, or use very very quickly: http://discussions.probrewer.com/sho...ight=fermentis

or

Go to homebrew store. Buy 10 11gm packets and pitch those. Probably costs the same.