Repitching dry yeast

[Velnerj]

I've bumped into this idea a few times on this forum. It's not so much the idea of repitching dry yeast (or any yeast for that matter) but it's the idea that the yeast doesn't reach its full potential until after a few iterations/repitches. It's a bit counter-intuitive to me but I'm interested to hear other people's experiences. Is it because of increased pitch rates? Is it strain dependent? Slight positive deviation from original strain? Too many questions....

Personally I only use dry yeast so that's why this thread is limited to that but liquid yeasts could also be addressed here too.

My own personal brewing style is not set up ideally for repitching as I brew once every 2-3 months. As I see it that's probably too long to hold yeast (without freezing with glycerine). But I would also be willing to hear others who have stretched their repitches that long with varying success?

If there is any truth to the idea that repitching equals better beer I may have to rethink my brewing practices...

 

[DBhomebrew]

I've pitched harvested slurry after 2-3 months with success (measured by whether I enjoyed the batch), but by that time I do think you're losing out on the power of fresh slurry.

For that, I'd pitch some of the harvested slurry into a starter. I use a Shaken, Not Stirred starter for which the only special equipment I needed to purchase was a 1/2 gallon mason jar. Some use emptied water/milk jugs.

With an S-N-S starter, I pitched Pub from a 5mo 8-or-so generation slurry. Attenuation was a bit over 80%, too high really. I didn't harvest any slurry from that batch. Will buy new Pub when English yeast weather comes back around.

 

[hotbeer]

Once it's pitched the first time it's no longer dry yeast. So pretty much all the practices you do with liquid yeast apply.

The dry yeast makers say it's at it's best the first time. And even if it's not, it's pretty durn close. Besides, what does "at its best" do? Does that mean it ferments out a day sooner or is more alcohol tolerant for big beers?

 

[Velnerj]

Once it's pitched the first time it's no longer dry yeast. So pretty much all the practices you do with liquid yeast apply.

The dry yeast makers say it's at it's best the first time. And even if it's not, it's pretty durn close. Besides, what does "at its best" do? Does that mean it ferments out a day sooner or is more alcohol tolerant for big beers?

This is why it's counterintuitive for me. I would think that the yeast from manufacturers is pristine and offers the best case scenario. Repitches are bound to have something mixed in even if it is just trub and hop debris.

If it were just down to pitch rate we'd see increased results after the first repitch. But I seem to be reading claims that certain yeasts don't "get in their zone" (use whatever equivalent jargon) until pitch 4 or more...

 

[Wolfbayte]

For that, I'd pitch some of the harvested slurry into a starter. I use a Shaken, Not Stirred starter for which the only special equipment I needed to purchase was a 1/2 gallon mason jar. Some use emptied water/milk jugs.

I also save slurry in mason jars and it works well. I also don't see a difference between whether the original pitch was from dry or liquid yeast. If it's a good yeast, and more importantly came from a great batch of beer, I consider the yeast a keeper for another batch or two.

My fermenters have spigots. After racking beer into the the bottling bucket, I add 2-3 bottled waters to the slurry, swish it around, and fill sanitized mason jars from the spigot. I picked up the plastic mason jar lids and sanitize those as well. I use rubber bands from fresh asparagus and an old bread clip with the date/style written on it to keep them identified. The yeast keep in the back of the frig for up to several months for the next batches of homebrew, bread, doughnuts, pizza, etc. For baking, decant, take a 1-3 sanitized spoons full from the top, and toss the rest. For beer, decant, shake, and pitch the rest.

I usually try to limit this to 2-3 generations max and have not had problems yet. By way of example: in January I brewed Biermuncher's Centennial Blonde with liquid Voss Kviek, saving 6 mason jars of diluted slurry. The day we bottled it, we pitched 2 mason jars of fresh slurry, trub and all with no decanting (it hadn't settled yet) into a rusty, muddy blonde ale that came out great for my friend's wedding. Didn't save any slurry from the muddy batch due to coloration, but prolly could have. Next we pitched one of the originals into an 805 clone, and a month later pitched one from that into a Hef that fermented at 90. Next batch, we pitched slurry from the 805 clone into an Irish Red that fermented at 64. All came out fantastic.

Disclaimer: I don't get a lot of hop or cold break material in the trub, because as part of my aeration process, the chilled wort goes through a strainer as it enters the fermenter. I also use hop bags on brews with more than a 2 oz hop bill. YMMV.

 

[BrewnWKopperKat]

the idea that the yeast doesn't reach its full potential until ...

This is why it's counterintuitive for me. I would think that the yeast from manufacturers is pristine and offers the best case scenario.

Over the years, in the anecdotal stories that I have read, there is a re-occurring theme of "strain XYZZY producing off flavor alpha" on the first pitch. Re-pitching (or making a starter on first use) often, but not always, eliminates the problem. I won't name strains in this reply - but there are a couple of them.

Is there something to it?

• Perhaps, people taste beer different.
• Perhaps, there was (but no longer is ) something to it - as processes for packaging active dry yeast do change over time.

Focusing on ancedotal stories that mention specific strains, provide complete recipes, and provide appropriately detailed process descriptions may be both interesting and helpful.

---

A split batch - wet vs dry with yeast from the same package - might be an interesting experiment. The thought would be to make a starter with half of the package & pitch the other half dry (or re-hydrated).

 

[AlexKay]

This thread and the other one have convinced me to do a side-by-side. Plan is to make a batch with a dry yeast, ferment and keg it, and make the same recipe using the yeast from the first run. I was going to do W34/70 and start with a Bo Pils I’m brewing tomorrow, but I could be persuaded to change to another yeast (and recipe) if others have a better idea.

 

[davidabcd]

You're all better and more conscientious brewers than me. I will never find out if a dry yeast improves with use or reaches a higher plateau from reuse.
You're all super-brewers in my book.
Note: out the yeast goes after each batch for me.

 

[Velnerj]

This thread and the other one have convinced me to do a side-by-side. Plan is to make a batch with a dry yeast, ferment and keg it, and make the same recipe using the yeast from the first run. I was going to do W34/70 and start with a Bo Pils I’m brewing tomorrow, but I could be persuaded to change to another yeast (and recipe) if others have a better idea.

Better would be a to brew the first batch. Harvest the yeast, brew a second batch and split that one between new and reused yeast. This will eliminate more variables. But that's just a suggestion, easy to be the armchair brewer when I won't be doing the work.

 

[AlexKay]

Sold. I'll use the yeast from an adjunct lager I'm already fermenting with 34/70 (whole cake or pull off a cup or so?) and make 2 Pilseners in a couple of weeks, one with that yeast and one with dry.

 

[BrewnWKopperKat]

This thread and the other one have convinced me to do a side-by-side.

Are you looking for anecdotally reported differences (pitched dry vs re-pitched)? Or will this be a group triangle test? Or a BJCP-like judging?

Please record the "best by" date for the yeast used.

I'm not aware that W34/70 is one of those strains where "strain XYZZY producing off flavor alpha". If it is, be sure to know how to look for that off flavor.

"Extract darker than expected" has mutated over the last couple of years into "Use fresh LME" with a single statement from 2005 that can be confirmed with basic recipe and a couple of additional process steps.

With active dry yeast, it may be that there are a number of 'super tasters' who taste something that the rest of us can not.

Looking forward to reading about the process and the results.

 

[McMullan]

Yes, you're underpiching yeast programmed to survive the industrial drying process when following manufacturer's recommendations. How generous to prop up their profits! Repitching - according to good practices - is highly recommended, not just to save money.

 

[BrewnWKopperKat]

@McMullan , @Oleson M.D. : what would each of you consider good practices for repitching?

 

[McMullan]

@McMullan , @Oleson M.D. : what would each of you consider good practices for repitching?

Fresh yeast in top condition. You can't buy it, you have to prepare it yourself.

 

[DBhomebrew]

whole cake or pull off a cup or so?)

I'd think the pitch, whether dry or harvested, should be roughly equal in terms of cell count.

Sure a pint (or qt!) full of harvested slurry may out perform a pack or two, but how does that compare in terms of pitch rate?

Is the advantage of harvested slurry coming from the fact that it can be the equivalent of pitching a starter 100% of batch size?

 

[BrewnWKopperKat]

@McMullan , @Oleson M.D. : what would each of you consider good practices for repitching?

@McMullan , @Oleson M.D. - a follow-on question: can you share your practices for repitching (including evaluation techniques)?

I see there are some ideas (and hints at ideas) over in Repitching dry yeast .

Offering well described processes could help accelerate the timeline for those willing to put together various tests / experiments.

 

[AlexKay]

Are you looking for anecdotally reported differences (pitched dry vs re-pitched)? Or will this be a group triangle test? Or a BJCP-like judging?

I have to admit, the main question I'm trying to answer is "Can I make beer that I like more if I re-pitch yeast?" So I'd just been thinking I'd make it, taste it, and report back. But my secondary question is "Can I make beer that other people like more?" I'll see if folks at my club are interested in doing triangle testing for me.

 

[BrewnWKopperKat]

the main question I'm trying to answer is "Can I make beer that I like more if I re-pitch yeast?"

Thanks. That reads like a good starting point for an interesting 'experimental' batch (or two). Looking forward to reading the results!

 

[Miraculix]

For this test, I would just use the complete yeast cake. For the other test beer, I would use three packs of dry yeast, just to make sure that it is not the cell count that gives the advantage, should there be a difference in the final product.

It is hard to guesstimate (the calculators are doing nothing more than guess work) the exact cell count of a slurry, that's why I've chosen three packs of dry yeast. It should be enough in the ball park area to make sure that there is not a significantly lower cell count in the dry batch.

 

[DBhomebrew]

For this test, I would just use the complete yeast cake. For the other test beer, I would use three packs of dry yeast, just to make sure that it is not the cell count that gives the advantage, should there be a difference in the final product.

It is hard to guesstimate (the calculators are doing nothing more than guess work) the exact cell count of a slurry, that's why I've chosen three packs of dry yeast. It should be enough in the ball park area to make sure that there is not a significantly lower cell count in the dry batch.

But is three packs really roughly equivalent to a full cake?

Let's call the cake particularly fouled with trub, maybe knock it down 50%. That's still a 2.5 gallon starter!

 

[Miraculix]

But is three packs really roughly equivalent to a full cake?

Let's call the cake particularly fouled with trub, maybe knock it down 50%. That's still a 2.5 gallon starter!

The yeast would need to grow 1.5 generations from one pack to create the same cell count as 3 packs, I think this is quite possible. Actually probably still a bit more yeast in the cake but some might day... ball park, three packs is ok I guess.

 

[AlexKay]

I don’t think we should adjust to the same pitch rate, necessarily. My question really is, given the way dry yeast is usually used (2 packs/5 gallons for a lager), can one make better beer by (pitching on a yeast cake/harvesting yeast slurry/etc.)? Otherwise you have to answer whether normally pitched dry yeast is different from overpitched dry yeast.

 

[CascadesBrewer]

I have to admit, the main question I'm trying to answer is "Can I make beer that I like more if I re-pitch yeast?" So I'd just been thinking I'd make it, taste it, and report back. But my secondary question is "Can I make beer that other people like more?" I'll see if folks at my club are interested in doing triangle testing for me.

I have harvested and repitched dry yeast. These days I am more and more just using fresh packs of dry yeast and not messing with harvesting, storing, and making starters, but I have at least harvested and pitched dry S-04 (a few years ago) and Voss (recently).

I wish I had paid more attention to my S-04 repitches. That is a yeast that I have noticed a slight "twang" with some beers. I have read people say that only occurs with the initial pitch of dry yeast. I am a little curious about doing an experiment comparing fresh dry S-04 vs harvested S-04. The issue is, I would rather just use a dry yeast that I enjoy more than S-04.

As mentioned, getting similar pitch rates between a pack of dry and harvested yeast will be one challenge for a valid experiment. If one batch gets 80B cells and one batch gets 250B cells, it will be hard to pin down the cause of the difference. That said, as a homebrewer if harvesting and repitching makes beer you enjoy, then the underlying reason might not matter much.

I have read that in the production of dry yeast, there is a step before drying where the yeast is stressed. This forces it into a state where it is better able to survive the drying process. I could definitely see where dried yeast could produce some different results on the first pitch, vs the same liquid strain or harvested yeast.

 

[BrewnWKopperKat]

I wish I had paid more attention to my S-04 repitches. That is a yeast that I have noticed a slight "twang" with some beers. I have read people say that only occurs with the initial pitch of dry yeast. I am a little curious about doing an experiment comparing fresh dry S-04 vs harvested S-04.

Were you able to determine a pattern for which beers might that off flavor?

From other anecdotal stories that I have read, the off flavor is present in every batch they brewed.

The issue is, I would rather just use a dry yeast that I enjoy more than S-04.

With a couple of dry yeast options available for many styles of beer, this makes a lot of sense.

 

[CascadesBrewer]

Were you able to determine a pattern for which beers might that off flavor?

I used S-04 for years and enjoyed it. While sampling one of my beers, a guy (that is a VERY good brewer) at my homebrew club pointed out that he got a bit of a sour twang from S-04 so he stopped using it. Hmmm...I did noticed a bit of a twang. I brewed a split batch with WLP013 and S-04 and the twang was very noticeable in the S-04 batch. While preferences were split among people that tasted that spit batch, I had a strong preference for WLP013, so WLP013 became my standard yeast for similar styles. That was maybe 4 years ago.

I have mostly been brewing Pale Ales, IPAs, and Belgians for the past 2 years. Since I have been moving more toward dry yeast, I want to put some effort into evaluating more dry English-style yeasts in English-style beers.

 

[AlexKay]

I'm not a fan of S-04: not crazy either about its taste or its fermentation performance. I've gotten decent results with K-97 in English Ales, even though it's more a German yeast. Lately I've been using Lallemand London and been very happy with it.

 

[BrewnWKopperKat]

Thanks @CascadesBrewer and @AlexKay .

 

[Velnerj]

My anectodal experience with S-04 is similar to the above experiences. I made an English ale (bambardier homage) and there was definite sour twang that I could power through but turned me off to the Yeast. Looking back at my records it seems I harvested that batch and repitched into a chocolate stout. Full disclosure my harvesting and repitching practices were shady then. However, there was no sour twang but the beers flavors were subdued and a little bland. I brewed that chocolate stout (with a minor change) with US-05 and it was a homerun.

Definitely not hard science here but it has been enough for me to look for other English ale yeasts.

Just like @CascadesBrewer I'd rather experiment with other yeasts than go back to S-04.