Effects of grossly over pitching yeast ?
Posted: Tue Sep 05, 2017 5:58 am
I'm still alive, and still suffering the same issues anytime I try to brew with even the most conservative lager fermentation scheme. Namely, underattenuation, and boat loads of acetaldehyde and diacetyl. I've tried different yeasts, shaken starters, stirred starters, pure O2 with flow meter at pitching, sterile air pumped for several hours at pitching. Fermenting warm (~ 10 C), cold. Raising temp for the classic D-rest even. Yeast nutrients, including the fabled Servomyces.
My FFT show good attlenuation (e.g. 1.048 - 1.008 or better). My ferm temp probe is calibrated. My wort ph is good (~ 5.2 into fermenter). No O2 meter yet.... but several hours of air through an air stone ought to get things up and away.
So over pitching. My last batch I tried was 10 liters. I pitched approx 170 ml of super dense slurry. Too much? FFT was 1.009 (mash temps were a bit messy), but the batch got stuck at 1.0125 ish (bottle conditioning/spunding).
I've been so concerned with getting 'enough' yeast, thinking this is the issue (i.e. not enough) that it occurs to me I may have been pushing the wrong direction. As anecdotal evidence of this, I did a Dunkel a long way back, and pitched assuming approx 4 billion cells per ml of dense sediment. This beer turned out well, albeit very sweet due to using too much munich II (100%).
A very subjective question. How much acetaldehyde and diacetyl is in your beers at transfer ? For me, I can't even taste the malt, or hop character -it's that bad.
My plan is to direct pitch one vial to 10 liters of wort (in case my starter method is doing harm), and aerate with sterile air for 5 or so hours. See where that gets me. It will be many magnitudes less yeast than I've been pitching.
Sorry for the long post, as ever. I appreciate all of your past advices, and appreciate your patience.
Nick
My FFT show good attlenuation (e.g. 1.048 - 1.008 or better). My ferm temp probe is calibrated. My wort ph is good (~ 5.2 into fermenter). No O2 meter yet.... but several hours of air through an air stone ought to get things up and away.
So over pitching. My last batch I tried was 10 liters. I pitched approx 170 ml of super dense slurry. Too much? FFT was 1.009 (mash temps were a bit messy), but the batch got stuck at 1.0125 ish (bottle conditioning/spunding).
I've been so concerned with getting 'enough' yeast, thinking this is the issue (i.e. not enough) that it occurs to me I may have been pushing the wrong direction. As anecdotal evidence of this, I did a Dunkel a long way back, and pitched assuming approx 4 billion cells per ml of dense sediment. This beer turned out well, albeit very sweet due to using too much munich II (100%).
A very subjective question. How much acetaldehyde and diacetyl is in your beers at transfer ? For me, I can't even taste the malt, or hop character -it's that bad.
My plan is to direct pitch one vial to 10 liters of wort (in case my starter method is doing harm), and aerate with sterile air for 5 or so hours. See where that gets me. It will be many magnitudes less yeast than I've been pitching.
Sorry for the long post, as ever. I appreciate all of your past advices, and appreciate your patience.
Nick