Some trouble with 34-70 Repitch... Opinions welcome.

Ingredients
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I’ll try to make this as brief as I can.

Monday 5/26 I brewed 2 batches of what was to be American Lager.  Grain bills differed slightly due to available ingredients, but both were 18.5# grist for 10 gallon (38L) batches.  One gravity was 1.046 the second 1.050.  One batch went in a SS Conical and the other in 2 Big Mouth Bubblers (carboys).

My last lager brew was late Nov 23.  I saved 2 jars of trub in the fridge and had figured on using them, which I did.  Pitch temp was about 68F (20C) and the yeast was colder than the wort.  Ran an Oxygen stone in all 3 for about 15-20 seconds each, a process I would avoid when using new dry yeast. Decanted and shook the jars and pitched roughly evenly.  Then gave a stir to each wort just to mix things well.  Each jar had what I’ll estimate to be 100-150ML settled slurry. About an inch in the bottom of a quart jar, maybe 1-1/4". This very low amount really surprised me.  Ale would be 80% cake and 20% beer.

2 days passed with temp set to 61F (16C) and positively no activity from any of the 3 vessels.  Getting worried about possible problems at this temp, for too long, with no activity, I decided at 6pm Wednesday 5/28 to add more yeast.  What I had on hand was 2 new packs of 34-70 dated 12 2024, and 2 packs of S23 dated 5 2018…  (cringe, yea, been a while since I needed that stuff).  Having no alternatives, I added both S23 to the SS Conical 1.046 batch and the 34-70 one pack each to the Bubblers (1.050 batch).  Activity was shown in all 3 by morning, at which point I set the temp so it would lower to 55F (12.7C) just to avoid too fast a fermentation and a huge mess. Wasn’t convinced about my temp decision…

Normally, I would not add O to the wort if pitching dry yeast, though I have before. I guess time will tell, but does anyone feel there will be any issue given these circumstances?  I have never before had lag like this on a beer that was re-pitched.  To be fair, I do not often use Lager yeast. I’d say 90% of the time I make ales.  What stinks is now I have what was probably an unhealthy original pitch which I really don’t know if it was even alive…  Mixed with new yeast that, well, I am pretty sure the new 34-70 was ok, but the S23 being 6 years old (refrigerated, not frozen during that time) is a crap shoot.  Did all 3 take off only because I added yeast? Did the original yeast take off with the new yeast having never taken effect, or do I have a combination of both?  And, having written notes that originally 3 packets of 34-70 went in last Nov batch, I conclude at $7 ea, I’ve got $50 in this yeast which is now a Frankenstein in the one fermenter (where I typically harvest from) and the other two I’ve got what is likely not the most healthy yeast cake coming.  It pains me to think I might dump all this out at the end of the process, hence the request for opinions.

I found another thread about re pitching 34-70 from around 2020, and read all 6 pages of that. It did digress some from the original topic but was quite informative. https://www.homebrewersassociation.org/forum/index.php?topic=30055.15

TIA

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If the yeast was 6 months old, viability is definitely questionable. I would have used a bit of it to make a starter.

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I’ve never done that before with slurry. Anytime I ever did a starter I began with new yeast. Not that I have a ton of experience with starters, but I do have a stir plate and 2 L flask.

How would I know how to formulate the starter if I don’t know the viability of the yeast? I don’t have the equipment or experience in counting cells, so other than the volume and the age, that would be the only way I could estimate what I’m beginning with.

In the past I would just wing it, assuming the slurry was a considerable over pitch, which in most cases was probably true. I see there are folks here who say overpitching is not a great practice, at least not when you are serially pitching the yeast. They advocated a slight under pitch so there was enough new yeast cells. But I never try for that many generations out of it before I start over. I think I read on one of the manufacturer sites that they recommend not more than 10 times repitching dry yeast. That might have been from Lallemand. I don’t think I’ve ever gone beyond five. In this case it was only the second use.

I think I’ve missed out on a pretty good learning experience on this batch.

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IMO, cell count is an unnecessary distraction. A stir plate is unnecessary.  I would have used a few Tbsp of the slurry to make a SNS starter. It’s not about the number of repitches. It’s about having healthy, active yeast. While overpitxhing can have issues, they’re nothing compared to underpitches.

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I had to Google what SNS even was. Interesting idea. It was only last year I finally made a stir plate. Now you’re telling me to let it collect dust. LOL

I did some reading on it, I will keep that in mind.

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Mine has been collecting dust for at least 10 years. In case you didn’t run across it, here’s some more info…Shaken, not Stirred: The Stir Plate Myth Buster | Experimental Brewing

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That was the first page I found when I did my web search. I’ve been reading ever since. Probably should be weighing out minerals for tomorrow and perhaps try one of those starters beginning right now.

Thanks for the info. I’m typically not one to jump right on the new Wiz Bang technique, but this doesn’t seem likely to make my beer any worse than the stuff I have in the fermenter now. LOL

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I understand what you’re saying. It took me quite a while to try it after I heard about it. It’s the only way I’ve done it since.

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Everyone says to pitch at high krausen. Often recommending 12 to 18 hours for the starter. What is the window of opportunity for that H.K.?  Meaning, I had lag with my beer, what if the yeast lags in the starter? If I make a starter on Saturday for Sunday and it isn’t ready, I’m not able to wait for Monday, I’m in trouble.  I did my ale yesterday the old way for that very reason. I suppose if I make it far enough in advance I can just rejuvenate it with another buildup if it’s slowing down.

I usually brew in spurts,  there simply isn’t time for me to brew every weekend.  The fact is, I often use yeast that’s months old. I saw info yesterday that repitching anything older than 7 days was problematic.  That might be ok for a commercial brewer, but I’d be filling the swimming pool with beer if i did that. So for me, stir plate or no, I’ll be bringing older yeast back to life fairly often.

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My experience is that missing it by maybe 12 hours or so isn’t a big deal. I often, maybe usually, use older yeast. Treated properly I haven’t found it to be a problem.

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Airlock activity was essentially stopped this morning. I didn’t take a gravity reading yet but it’s visibly ‘finished’.  I’ll let it continue sitting for a while yet and then begin cold crashing later.  I’ll likely allow it to warm up some for a few days, then slowly start dropping the temp. Hopefully this is another wonderful mistake.

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I would never used 6-month old yeast slurry in a lager without making a starter.  The accepted timeframe for that is usually around 3 weeks.  I would expect it to eventually take off but I would be twitchy about the yeast’s health and ability to take the gravity to where it should be for an American Lager and since this is a style where flaws can’t hide, I would be worried about the overall flavor of the beer.  We learn by screwing up batches of beer.  I can’t count how many “experiments” of mine went down the drain.  I have always said that yeast is by far the most mysterious part of the hobby because it’s absolutely necessary, it’s a living organism, we don’t know how many cells are available, how many are dead, in poor health, if the yeast has mutated, etc.  I respect the yeast.  :smiley:

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As a non-commercial brewer, hobbyist, often brew day springs on me when time becomes available and that’s sort of what happened here.  It wasn’t till I went to get the yeast out of the fridge that I saw there wasn’t all that much in the jars.  I don’t think I ever saw anything settle that much before. Other yeast I used this past weekend took off immediately (March harvest) and had 80%-85% full slurry in the jars.  Both Nottingham.  These had been stashed behind and I just hadn’t seen it…  Still, I figured there was enough, I mean, after the wort is in the fermenter there wasn’t many choices. :D  I just don’t think I ever saw that much yeast take that long to get going before.

From now on I’ll try to do a starter if it’s getting long in the tooth.  I never had what I’d call terrible results before, but, I don’t know how many times I have used yeast harvested that long before either.  Most of my notes are on Non-Volatile-Media (paper!).  So admittedly, searching is a bit slow… I don’t even know if that data was saved many years ago.  As I get farther and farther along in my brewing history, I make not of more and more stuff.  I can’t tell you how many times I wish I’d noted some of the ‘unimportant’ stuff.

I was on Ebay earlier looking at Microscopes… Like I need yet another step to take me forever on brew day…

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It’s not that it wasn’t enough … it’s that it was not active.  You can’t have yeast blobs in the fridge for 6+ months and then just drop them into fresh wort without a possible setback.

I used to “save yeast” but now I get a strain up and running (starter for a lager yeast, probably a swollen Wyeast pack for an ale) and then I brew with that strain multiple times in a row.  I wait until I have a couple 2-3 empty kegs and then start.  I don’t let more than 3 weeks time pass between brewdays so the yeast is always active and ready to go.  But you don’t have to do that if it doesn’t fit your schedule.  Dry yeast has come a long way.  Pick up some Diamond, 34-70, S-23, Nova, S-04, etc. and keep it around for a spontaneous brewday.  You can absolutely repitch a dry yeast slurry but the same rules apply … about 3 weeks.  Or … make starters.  I hate, hate, hate making starters so I try to use a blob of yeast a good 7-8 times before I retire it.  I’m using Omega 113 right now and I just brewed my 6th beer with it.  Two more are scheduled.  Then I’ll retire it and start the next strain … Omega Bayern.

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Interesting procedure you have there.  I’m not the biggest fan of doing starters either… Maybe I was reading wrong, but it sounded in one discussion here as if a person does a mash and brews their starter malt from grain. Ahhh, ok… And with DME @ north of $7/lb, I could see me doing that too.  I need my head examined.

This last 2 brew days I tried something I’ve never done before, 2 concurrent batches.  Meaning, get the first sparge going and have the second mash ready to begin as soon as the mash tun is empty.  Do the #1 boil and #2 mash at the same time, then finish the #2 boil while working on the #1 transfer to the fermenter.  It began as a way to save time making 2 10gal lager batches in one day, but this past weekend it was just a time saver making an Irish Red and Pale Ale.  I will say it works quite nice.  I had not brewed in months due to working on my house projects, and now I should be getting close to putting the brewing equipment up for a while longer.  I need to make a Kolsch yet because that and my PA are going to kick literally any pour now.  There’s no Irish Red currently, (a sacrilege).  So when they kick all I’ll have is stout and porter at 7+%, and a IIPA at 8+. Not the best stuff for school nights. :D.

Nearly every fermenter I have is full at the moment. There’s 2 old glass carboys still empty. I used one of them and a bucket for the last batch, neither of which has had beer in it for at least a decade.  So, something needs finished and kegged before any more brew days…

It’s a challenge balancing all my wishes.  A) Don’t run out of beer. B) Don’t spend every weekend brewing beer.  C) Don’t end up with more beer than you can drink before it’s flavor profile degrades… D) Don’t entertain so often that I can’t balance production and consumption… :smiley: When I have gatherings at the house, they can go through a LOT of beer!

Really, my Kolsch is the tricky one that I love from young to about 3 months, but after that it’s not ‘quite’ as good. That one I could do more often if time wasn’t an issue. I’d love to brew it ahead and just store it, but I am not sure that would work.  From what I understand, in Germany it’s served super young. Like, force filtered from the fermenter and then straight to the stein.  I read where they often announce when it’s coming on so you can get it the first day it’s ready.  I can see the reason for that because it’s really interesting in it’s young state. Even though I don’t / can’t filter mine, it’s still pretty amazing day 1.  At least by my standards.  I’ve never been to Cologne (Koln) to have a real one.

But I digress. Thanks for the tips, and while I may not use them right away, I’ll store them away for sure.  Cheers!

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I checked the gravity’s tonight and I can’t complain about the attenuation, and while both beers taste very different, they both seem like they’ll have great promise. I have a hard time judging outcomes from beer that’s hardly finished in the fermenter, but there was no off aromas or flavors for sure.

My stainless steel conical got the first batch which started at 1.046 or 11.4 brix and finished at 5.6 which amounts to 5% alcohol and a finished gravity calculated to 1.008. That’s the stuff I added the 5-year-old s23 to. Both of these have been set to 70° since yesterday but the actual temperature, while I didn’t check it today, is much lower still I’m sure. I’m just not making an active effort to cool it anymore. I’ll start the cold crash soon as well. It’s probably in the mid 60s and I really don’t even care.

Batch 2 in the two big mouth bubblers in the lower half of the same freezer started at 1.050 or 12.4 brix. It finished at 6.0 brix which calculates to 1.007 as a finished gravity for a 5.55% abv. Since I brew so few lagers, I hesitate to try to claim anything about the flavors. I would say if anything I hope the hops will creep a little bit because they’re both quite mild. I would say the beer in the conical even has a sweet foreground to it right now but what beer that hasn’t left the fermenter doesn’t have some of that.  I only removed about a teaspoon to check with the refractometer and tasted what I didn’t use so, not a great big sample.

I fully expected some attenuation problems given all the lag this had. I’m downright shocked at where they ended up. Also shocked that the 2018 s23 ended up where the 2024 3470 did. Although it’s very possible the initial pitch of yeast is what really did all the heavy lifting and the extra yeast I threw in was just a complete waste. I’ll never know. That really sucks because they’re $8 a pack and I added four of them.

I’ll try to continue to add updates because I hate when I look back at a really old thread that looks interesting and it’s just chops off and you never find out what the beer was like. I don’t expect this to be some stuff I’m going to enter in a contest or anything, but I’m pretty sure it’s not going to be my worst beer ever. I’m going to be drinking this stuff. It tastes plenty yeasty still but it also has about half the yeast in suspension yet. Seeing through that though, there’s a pretty clean beer underneath if I can get it to clean up.

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Just to reiterate what Denny said in the start of the thread, 6 months old slurry is way too old to use without a starter. The yeast will have died off drastically and their viability will be extremely low. You can make the argument that yeast is the most important ingredient in beer–you can’t make beer without it. And healthy yeast is the key to making delicious beer.

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I kegged some Tuesday night (2 BMBs) and tried some last night since there’s nothing else in the house to drink.  It wasn’t carbed enough yet but tasted great. Its cloudy yet, no surprise 1 day from the fermenter and no finings.  The head retention is abysmal.  Is that normal given it’s not had time to clear yet?  I need to look and see what the grain bill was because this has the worst head retention I’ve seen in many years.  Maybe ever. It pours a beautiful creamy head from the tap, but after it dissipates the surface hasn’t got a single bubble on it.  It’s not carbed enough to swirl it and generate more.  I know I didn’t add anything to help head retention, but holy smokes, I do a double decotction Kolsch that can hold foam overnight, and it doesn’t have any specialty malts either.

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Re: head retention…yeast health and fermentation process has a lot to do with foam.  Since you were starting with likely unhealthy yeast, it kinda makes sense. Brew Your Own: The How-To Homebrew Beer Magazine - Story Index - Head Retention - Getting Good Beer Foam: Techniques

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Cool article, thanks.  Maybe as it clears it will help some, but it looks like it’s just going to be weak on the foam.  I’ll be curious to see how the subsequent batches work out. It’s still not a dumper, just doesn’t hold a head for any length of time which doesn’t bode well for sitting in the glass a long time.  Moral of the story, drink faster!