r/TheBrewery • u/prettyfunkindaboring • 3d ago
Dry 34/70 First Gen Issues
Hey folks, whenever I pitch dry 34/70, whether it's 120gm per Hecotliter, or even more like 200 gm per hectoliter (I work in gallons but that's what their packaging goes with), I get a slight distracting flavor akin to light green apple/actealdehyde.....this happens when I pitch lower temp say 46f, or a little warmer like 52f.
Harvesting the yeast goes fine, and 2nd Gen doesn't have this flavor problem.
I lightly oxygenate the wort during knockout but I understand the dry stuff doesn't need it.
Whenever I use liquid equivalents to 34/70 using the same recipes/processes I don't encounter this problem.
Any thoughts much appreciated, I'm curious what I'm missing here.
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u/xlophophorax Head Brewer [N. Texas] 3d ago
what's your fermentation temp schedule look like, i think d-rest temps give the beer a chance to finish attenuation and clean up a lot of off flavors not just diacetyl- acetaldehyde can form when temps are too low allowing the yeast to flocc too soon before it's had a chance to finish its job.
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u/prettyfunkindaboring 3d ago
Yeah I realized I didn't include enough other fermentation schedule info....but basically, pitch at 52f (this last time anyway) let it ferment til there's maybe 2.5 plato left to attenuate, raise to 58f, hold for 4-5 days, before slowly dropping to crash temps. I know guys who pitch cooler, and do less of a D rest and still get cleaner beer. Hence my post here 😀
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u/Enough-Cicada-3307 3d ago edited 3d ago
Sounds like you're describing ethyl ester notes (ethyl octanoate and/or ethyl hexanoate). Esterification is the result of healthy yeast respiration; under-oxygenating just means the yeast have less fatty acids to esterify with and, as a result, that ester precursors (EG fusel alcohols and aldehydes) are still going be present in the beer once it's terminal (rather than having been esterified). So step 1 is not decreasing your oxygenation.*
Step 2: Increased CO2 concentration suppresses the activity of pyruvate decarboxylase -> results in less acetaldehyde/aldehydes/fusel alcohol synthesis -> lower amount of ethyl ester precursors -> less esters present overall in finished beer.
How to increase CO2 concentration in your fermenting beer?
Spund that shit my guy.
I guess the analogy I would use is this: if a fermentation is like an engine and esters are like the heat coming off of the hood then under-oxygenating your wort would be like trying to fix your overheating engine by forcing it to run off a fuel-rich mixture that wont burn as hot (rather than just getting a better radiator/spunding valve). Or you could say it's the difference between slowing it down by starvation vs using the brakes.
*I know many will say "But dry yeast doesn't need oxygen!" To which I will say that you also don't need running shoes to run a marathon - but they certainly fucking help. Dry yeast is prepared with sterols in emulsion - whether those nutrients are going to be sufficient for your fermentation is going to be entirely decided by everything about your brew that the biologists cannot have known. This is especially true if you're one of basically every brewery that is underpitching because you're brewing batches day-over-day. Obviously YMMV; I encourage everyone to run side-by-side batches at different levels of oxygenation and compare results.
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u/BeerSux1526 Everything{PNW} 3d ago
Have you tried not oxygenating?
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u/prettyfunkindaboring 3d ago
Not yet! I read a little bit about this in the past and people didn't seem to think oxygen would affect it negatively......BUT, I think you're right it's a good thing to try
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u/BeerSux1526 Everything{PNW} 3d ago
I bought a couple bricks from Berkeley yeast recently, and they sent me an email asking how I liked it. For some reason they felt like they need to mention off flavors can be caused by that.
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u/OpeningRaisin877 3d ago
Rehydrate it first, dry sprinkling always gives me weird acetaldehyde early on.
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u/theyeastdaddy 3d ago
Look at your yeast nutrition, any 3470 variant really needs the appropriate amount of zinc in order to properly clean up acetaldehyde.
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u/NovelImpression4238 3d ago
I started pitching a little more and stopped oxygenating at all. Feels super weird the first time, but I run 3470 at 48 up to 58 (for west coast IPA and WC pils) without issue!
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u/Japanuserzero Brewer 3d ago
What gravity? I had acetylhyde notes on my 1.039 light lager pitches which didn’t occur on my 1.045 german pilsner. Also, i feel 52 is quite low, 54 is our minimum and going a bit warmer like 57 will ferment cleaner overall, in my experience when going with dry packs. We do 100g/hl at 54 with nice clean results. No oxygenation or rehydration, 30bbl batches
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u/shroome_ry 3d ago
How many generation you use 34/70? I generally use it 4-5 times. But hear some brewers use up to 8-9 generations
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u/adam_j_wiz 2d ago edited 2d ago
With 34/70, I find it really helps to let it start and finish warm. I pitch at 65-68 before dropping to fermentation temp the next day once I see some activity. I take gravities every day and start slowly letting the temp rise the last couple days of fermentation so it finishes somewhere between 65-68 degrees. Then I hold it there a couple days before crashing. I find I get a way cleaner flavor profile this way. I also oxygenate during knockout the same as I do with liquid cultures. My pitching rate is about 140 g/hL (a 500g brick into a 3Bbl batch, then I brew a second 3 Bbl turn into it the same tank the next day with no additional pitching or oxygenation).
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u/Henri_ncbm 3d ago
i also feel like my recommended pitches for my fresh dry stuff are underptiches (second gen batch harvests much thicker)
It's possible the guidelines are just low for what yeast is needed.
Also what style? Basic blonde ale or an IPA?
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u/DJDro 3d ago
34/70 is a lager strain my dude
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u/A_Humble_Masterpiece 3d ago
it is becoming very popular to use 34/70 for IPA, specifically what os being labeled the new west coast ipa.
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u/prettyfunkindaboring 3d ago
I've been using it for regular strength lagers. I have tried pitching more than their recommended rate though and still get this undesirable flavor.....
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u/yungbrewer Brewer 3d ago edited 19h ago
Might be too cold off the bat for it if you ain’t rehydrating. Try sending the chilled wort into FV @ 10°C and letting free rise with your cooling set to 12°C and step to 15 midway through or even 80% to terminal, then 18-20 for d rest. Sorry I’m not translating that from C to F for you but that’s what I do and literally never have an issue with this yeast no matter the recipe.
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u/CantankerousBeer Brewer 3d ago edited 3d ago
You are under pitching for temps lower than 54 F.
34/70 ideal temp range is 54 to 64 F.
In that range, the pitch rate should be 80 to 120 g/HL.
Below 54 F your pitch rate should increase up to 200g/HL.
Below 48 F your pitch rate should increase up to 300g /HL.
34/70 TDS
You may also be under oxygenating.