# Confessions of a Yeast Abuser **URL:** \ **Category:** Ingredients\ **Created:** [April 6, 2016, 7:21pm UTC](https://forum.homebrewersassociation.org/t/confessions-of-a-yeast-abuser/22946 "2016-04-06T19:21:19Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![denny](https://sea1.discourse-cdn.com/brewersassociation/user_avatar/forum.homebrewersassociation.org/denny/32/13092_2.png) [@denny](https://forum.homebrewersassociation.org/u/denny)\ **Post date:** [April 7, 2016, 3:21pm UTC](https://forum.homebrewersassociation.org/t/confessions-of-a-yeast-abuser/22946/21 "2016-04-07T15:21:20Z")
> [@brewinhard](#): > > > [@brulosopher](#): > > > > I like when the yeast abuses me [emoji53] > > Atta boy!  Now your thinking you dirty ~~old~~ young man. ---
**Author:** ![blair.streit](https://sea1.discourse-cdn.com/brewersassociation/user_avatar/forum.homebrewersassociation.org/blair.streit/32/9827_2.png) [@blair.streit](https://forum.homebrewersassociation.org/u/blair.streit)\ **Post date:** [April 7, 2016, 3:25pm UTC](https://forum.homebrewersassociation.org/t/confessions-of-a-yeast-abuser/22946/22 "2016-04-07T15:25:56Z")
I’m curious if you guys feel that you “compensate” in any way when you’ve abused your yeast? For example, if the yeast is old do you aerate more than you would otherwise or maybe throw in a little extra yeast nutrient? I’m asking because I’ve struggled with vitality on repitching in a couple of previous batches (yeast pooped out early on the second batch). I’ve been attributing this to inadequate aeration in the first batch or possibly waiting too long to collect the yeast. That said, pitching lager yeast in the mid 40’s and fermenting at 50 may be too tough an environment to get away with yeast abuse. Thoughts? ---
**Author:** ![denny](https://sea1.discourse-cdn.com/brewersassociation/user_avatar/forum.homebrewersassociation.org/denny/32/13092_2.png) [@denny](https://forum.homebrewersassociation.org/u/denny)\ **Post date:** [April 7, 2016, 3:31pm UTC](https://forum.homebrewersassociation.org/t/confessions-of-a-yeast-abuser/22946/23 "2016-04-07T15:31:21Z")
> [@blair.streit](#): > > I’m curious if you guys feel that you “compensate” in any way when you’ve abused your yeast? For example, if the yeast is old do you aerate more than you would otherwise or maybe throw in a little extra yeast nutrient? > > I’m asking because I’ve struggled with vitality on repitching in a couple of previous batches (yeast pooped out early on the second batch). I’ve been attributing this to inadequate aeration in the first batch or possibly waiting too long to collect the yeast. > > That said, pitching lager yeast in the mid 40’s and fermenting at 50 may be too tough an environment to get away with yeast abuse. Thoughts? Nope, no compensation here…at least not in any consistent way.  And I abuse lager yeast just as you mention. Let me say right here that this obviously isn’t the best way to do things, and I don’t recommend yeast abuse as a regular practice.  You have to be prepared for the fact that you may lose a batch of beer.  But I’ve found I can get away with it more often than not. ---
**Author:** ![blair.streit](https://sea1.discourse-cdn.com/brewersassociation/user_avatar/forum.homebrewersassociation.org/blair.streit/32/9827_2.png) [@blair.streit](https://forum.homebrewersassociation.org/u/blair.streit)\ **Post date:** [April 7, 2016, 4:08pm UTC](https://forum.homebrewersassociation.org/t/confessions-of-a-yeast-abuser/22946/24 "2016-04-07T16:08:44Z")
Yeah the “punishment” I took was finishing at 1.024 instead of 1.019. Not the worst thing in the world. I just blended it with another batch and left plenty of yeast in suspension to lager for a bit longer. Not tragic… ---
**Author:** ![zwiller](https://avatars.discourse-cdn.com/v4/letter/z/f9ae1b/32.png) [@zwiller](https://forum.homebrewersassociation.org/u/zwiller)\ **Post date:** [April 7, 2016, 4:27pm UTC](https://forum.homebrewersassociation.org/t/confessions-of-a-yeast-abuser/22946/25 "2016-04-07T16:27:28Z")
Back when I was fighting dry beers it was suggested to me that due to the longer growth phase, the yeast kick into overdrive and over-attenuate when underpitched…  I bought into it, did some starters, and no change.  I still think this hobby is way more forgiving than we make it seem.  Anyone ever have a mash that didn’t convert?  Remember worrying about it?  ;D ---
**Author:** ![69franx](https://sea1.discourse-cdn.com/brewersassociation/user_avatar/forum.homebrewersassociation.org/69franx/32/10699_2.png) [@69franx](https://forum.homebrewersassociation.org/u/69franx)\ **Post date:** [April 8, 2016, 5:31pm UTC](https://forum.homebrewersassociation.org/t/confessions-of-a-yeast-abuser/22946/26 "2016-04-08T17:31:12Z")
> [@zwiller](#): > > Back when I was fighting dry beers it was suggested to me that due to the longer growth phase, the yeast kick into overdrive and over-attenuate when underpitched…  I bought into it, did some starters, and no change.  I still think this hobby is way more forgiving than we make it seem.  Anyone ever have a mash that didn’t convert?  Remember worrying about it?  ;D Nice  8) ---
**Author:** ![euge](https://sea1.discourse-cdn.com/brewersassociation/user_avatar/forum.homebrewersassociation.org/euge/32/5060_2.png) [@euge](https://forum.homebrewersassociation.org/u/euge)\ **Post date:** [April 11, 2016, 9:33pm UTC](https://forum.homebrewersassociation.org/t/confessions-of-a-yeast-abuser/22946/27 "2016-04-11T21:33:49Z")
I just repitched some lager-yeast but did it according to mrmalty. Pitching on a whole cake has not produced spectacular results for me. ---
**Author:** ![charles1968](https://avatars.discourse-cdn.com/v4/letter/c/9dc877/32.png) [@charles1968](https://forum.homebrewersassociation.org/u/charles1968)\ **Post date:** [April 12, 2016, 12:23pm UTC](https://forum.homebrewersassociation.org/t/confessions-of-a-yeast-abuser/22946/28 "2016-04-12T12:23:43Z")
I don’t buy the theory that pitching rate significantly affects flavour. The whole topic is full of pseudoscientific explanations, such as that underpitching causes stress (actually the opposite is true). Anyway here’s a 2008 paper suggesting that pitching rate makes very little difference to flavour, except for diacetyl level rising with high pitching rates ([Impact of pitching rate on yeast fermentation performance and beer flavour - PubMed](http://www.ncbi.nlm.nih.gov/pubmed/19018524)). Low pitching rate is completely fine in my experience. The only problem besides waiting a day or so longer is that there’s higher risk of infection before the wort is colonized by yeast. Abstract (my emphasis): [quote]The volumetric productivity of the beer fermentation process can be increased by using a higher pitching rate (i.e. higher inoculum size). However, the impact of the pitching rate on crucial fermentation and beer quality parameters has never been assessed systematically. In this study, five pitching rates were applied to lab-scale fermentations to investigate its impact on the yeast physiology and beer quality. The fermentation rate increased significantly and the net yeast growth was lowered with increasing pitching rate, without affecting significantly the viability and the vitality of the yeast population. The build-up of unsaturated fatty acids in the initial phase of the fermentation was repressed when higher yeast concentrations were pitched. The expression levels of the genes HSP104 and HSP12 and the concentration of trehalose were higher with increased pitching rates, suggesting a **moderate exposure to stress in case of higher cell concentrations**. **The influence of pitching rate on aroma compound production was rather limited, with the exception of total diacetyl levels, which strongly increased with the pitching rate**. These results demonstrate that **most aspects of the yeast physiology and flavour balance are not significantly or negatively affected when the pitching rate is changed**. However, further research is needed to fully optimise the conditions for brewing beer with high cell density populations. [/quote] A more recent paper ([http://onlinelibrary.wiley.com/doi/10.1002/jib.242/abstract](http://onlinelibrary.wiley.com/doi/10.1002/jib.242/abstract)) [quote]With increasing numbers of cells introduced into the wort, the content of the esters and fusel alcohols increased, while the acetaldehyde concentration decreased. These changes affected the final quality of the beer. [/quote] Which contradicts the popular homebrewers’ notion that underpitching makes yeast express esters more strongly because they’re “stressed”. Obviously I’ve cherry picked these quotes to support my argument, but the best anyone can really say about pitching rate & perceptible flavour is that there’s no clear scientific evidence of a relationship. ---
**Author:** ![zwiller](https://avatars.discourse-cdn.com/v4/letter/z/f9ae1b/32.png) [@zwiller](https://forum.homebrewersassociation.org/u/zwiller)\ **Post date:** [April 12, 2016, 2:52pm UTC](https://forum.homebrewersassociation.org/t/confessions-of-a-yeast-abuser/22946/29 "2016-04-12T14:52:59Z")
1. ---
**Author:** ![system](https://us1.discourse-cdn.com/brewersassociation/original/1X/f1a2211dcb353b921ed70873794a31db2031eccc.png) [@system](https://forum.homebrewersassociation.org/u/system)\ **Post date:** [April 12, 2016, 4:01pm UTC](https://forum.homebrewersassociation.org/t/confessions-of-a-yeast-abuser/22946/30 "2016-04-12T16:01:50Z")
> [@charles1968](#): > > I don’t buy the theory that pitching rate significantly affects flavour. The whole topic is full of pseudoscientific explanations, such as that underpitching causes stress (actually the opposite is true). > > Anyway here’s a 2008 paper suggesting that pitching rate makes very little difference to flavour, except for diacetyl level rising with high pitching rates ([Impact of pitching rate on yeast fermentation performance and beer flavour - PubMed](http://www.ncbi.nlm.nih.gov/pubmed/19018524)). > > Low pitching rate is completely fine in my experience. The only problem besides waiting a day or so longer is that there’s higher risk of infection before the wort is colonized by yeast. > > Abstract (my emphasis): > > [quote]The volumetric productivity of the beer fermentation process can be increased by using a higher pitching rate (i.e. higher inoculum size). However, the impact of the pitching rate on crucial fermentation and beer quality parameters has never been assessed systematically. In this study, five pitching rates were applied to lab-scale fermentations to investigate its impact on the yeast physiology and beer quality. The fermentation rate increased significantly and the net yeast growth was lowered with increasing pitching rate, without affecting significantly the viability and the vitality of the yeast population. The build-up of unsaturated fatty acids in the initial phase of the fermentation was repressed when higher yeast concentrations were pitched. The expression levels of the genes HSP104 and HSP12 and the concentration of trehalose were higher with increased pitching rates, suggesting a **moderate exposure to stress in case of higher cell concentrations**. **The influence of pitching rate on aroma compound production was rather limited, with the exception of total diacetyl levels, which strongly increased with the pitching rate**. These results demonstrate that **most aspects of the yeast physiology and flavour balance are not significantly or negatively affected when the pitching rate is changed**. However, further research is needed to fully optimise the conditions for brewing beer with high cell density populations. A more recent paper ([http://onlinelibrary.wiley.com/doi/10.1002/jib.242/abstract](http://onlinelibrary.wiley.com/doi/10.1002/jib.242/abstract)) [quote]With increasing numbers of cells introduced into the wort, the content of the esters and fusel alcohols increased, while the acetaldehyde concentration decreased. These changes affected the final quality of the beer. [/quote] Which contradicts the popular homebrewers’ notion that underpitching makes yeast express esters more strongly because they’re “stressed”. Obviously I’ve cherry picked these quotes to support my argument, but the best anyone can really say about pitching rate & perceptible flavour is that there’s no clear scientific evidence of a relationship. [/quote] One thing to remember is that a lot of these experiments are done with lager yeasts, because that’s where the industry money is.  There are also differences I’ve noticed even across ale yeasts, so what’s applicable to a pale ale might not be to a Belgian Saison. ---
**Author:** ![narcout](https://sea1.discourse-cdn.com/brewersassociation/user_avatar/forum.homebrewersassociation.org/narcout/32/7683_2.png) [@narcout](https://forum.homebrewersassociation.org/u/narcout)\ **Post date:** [April 12, 2016, 4:51pm UTC](https://forum.homebrewersassociation.org/t/confessions-of-a-yeast-abuser/22946/31 "2016-04-12T16:51:59Z")
> [@charles1968](#): > > Anyway here’s a 2008 paper suggesting that pitching rate makes very little difference to flavour, except for diacetyl level rising with high pitching rates ([Impact of pitching rate on yeast fermentation performance and beer flavour - PubMed](http://www.ncbi.nlm.nih.gov/pubmed/19018524)). This one came to opposite conclusion regarding diacetyl, though it was studying high gravity fermentation with lager yeast. I think this stuff is interesting and fun to read, but I don’t know if it is all that relevant to what I’m doing. “As expected, increasing the pitching rates led to faster fermentation rates and higher yeast cell counts. Formation of 2-methyl-1-propanol increased with increasing pitching rate, but the formation of 2- and 3-methyl-1-butanol decreased.  The pitching rate did not alter ester formation in these experiments, with the exception of isoamyl acetate, where the level declined with an increased pitching rate.  Lower pitching rates led to higher levels of diacetyl and 2,3-pentanedione. The effect of pitching rate on flavour compounds clearly merits further investigation.” [http://onlinelibrary.wiley.com/doi/10.1002/j.2050-0416.2007.tb00259.x/pdf](http://onlinelibrary.wiley.com/doi/10.1002/j.2050-0416.2007.tb00259.x/pdf) ---
**Author:** ![charles1968](https://avatars.discourse-cdn.com/v4/letter/c/9dc877/32.png) [@charles1968](https://forum.homebrewersassociation.org/u/charles1968)\ **Post date:** [April 12, 2016, 6:39pm UTC](https://forum.homebrewersassociation.org/t/confessions-of-a-yeast-abuser/22946/32 "2016-04-12T18:39:34Z")
> [@narcout](#): > > > [@charles1968](#): > > > > Anyway here’s a 2008 paper suggesting that pitching rate makes very little difference to flavour, except for diacetyl level rising with high pitching rates ([Impact of pitching rate on yeast fermentation performance and beer flavour - PubMed](http://www.ncbi.nlm.nih.gov/pubmed/19018524)). > > This one came to opposite conclusion regarding diacetyl, though it was studying high gravity fermentation with lager yeast. > > I think this stuff is interesting and fun to read, but I don’t know if it is all that relevant to what I’m doing. > > “As expected, increasing the pitching rates led to faster fermentation rates and higher yeast cell counts. Formation of 2-methyl-1-propanol increased with increasing pitching rate, but the formation of 2- and 3-methyl-1-butanol decreased.  The pitching rate did not alter ester formation in these experiments, with the exception of isoamyl acetate, where the level declined with an increased pitching rate.  Lower pitching rates led to higher levels of diacetyl and 2,3-pentanedione. The effect of pitching rate on flavour compounds clearly merits further investigation.” > > [http://onlinelibrary.wiley.com/doi/10.1002/j.2050-0416.2007.tb00259.x/pdf](http://onlinelibrary.wiley.com/doi/10.1002/j.2050-0416.2007.tb00259.x/pdf) If you dig around for the few published scientific studies, you’ll find conflicting results but next to no evidence for a consistent effect on flavour. I think the take-home message is that advice on pitching rate is likely to be another brewing myth waiting to be properly debunked. You’re right that it might be specific to particular strains. Until better evidence comes in, however, I’m going to continue disregarding all advice on pitch rates and pitching rate calculators. I’ve always thought estimated cell counts are wildly inaccurate anyway. And if you pitch a starter into the main wort, all the supposed flavour benefits of high pitch rate go out of the window anyway. ---
**Author:** ![system](https://us1.discourse-cdn.com/brewersassociation/original/1X/f1a2211dcb353b921ed70873794a31db2031eccc.png) [@system](https://forum.homebrewersassociation.org/u/system)\ **Post date:** [April 12, 2016, 7:22pm UTC](https://forum.homebrewersassociation.org/t/confessions-of-a-yeast-abuser/22946/33 "2016-04-12T19:22:41Z")
The benefit I see from using some kind of calculator is consistency and repeatability.  You may not know how many cells you’re truly pitching until you do a cell count, but your process is the same each time.  Of course, pitching a single smack pack is repeatable as well, but I find I get better results with a starter.  YMMV. ---
**Author:** ![charles1968](https://avatars.discourse-cdn.com/v4/letter/c/9dc877/32.png) [@charles1968](https://forum.homebrewersassociation.org/u/charles1968)\ **Post date:** [April 12, 2016, 8:22pm UTC](https://forum.homebrewersassociation.org/t/confessions-of-a-yeast-abuser/22946/34 "2016-04-12T20:22:53Z")
There’s certainly no harm in trying to be consistent. I do wonder if it matters as much as people claim though. Yeast multiply until they’ve consumed all the sugar and then drop out. It happens every time, however many you start with. I haven’t seen any compelling evidence that the starting number affects flavour, but I accept that it’s possible. ---
**Author:** ![klickitat\_jim](https://sea1.discourse-cdn.com/brewersassociation/user_avatar/forum.homebrewersassociation.org/klickitat_jim/32/6601_2.png) [@klickitat\_jim](https://forum.homebrewersassociation.org/u/klickitat_jim)\ **Post date:** [April 12, 2016, 8:31pm UTC](https://forum.homebrewersassociation.org/t/confessions-of-a-yeast-abuser/22946/35 "2016-04-12T20:31:26Z")
Since we’re on the subject. Is cold crashing considered yeast abuse? Guilty! Some time ago I caught a Brew Strong episode where Jamil said that he read a study while working on his yeast calculator that chilling rapidly causes yeast to express 30% more esters. He didn’t reference the study. I vaguely remember us talking it up here on the forum with many folks agreeing and some disagreeing. I was in the disagree side but admit that it could be my lack of detection skills. Just recently I heard him reference this study again on a Jamil Show episode. He still didn’t reference the study, but he did provide some additional info about it. Someone asked him how fast is too fast and he said that the study claimed you can chill 2F per hour without getting any negative effect. So, when I cold crash, there are two 6 gallon batches in my temp controlled chest freezer and I simply change the setting to 30F. It takes at least 24 hrs for the steadily running chest freezer to drop from 72F (ale final temp) to 30. 42 degrees in 24 hrs is less than 2F per minute. With lagers, 68F D rest to 30 is only 38F in 24 hrs. Apparently I’m not detecting extra esters because even when I let er buck I’m not chilling fast enough to get greater than 2F per hour. Proof that sometimes a little info = worrying about nothing. ---
**Author:** ![denny](https://sea1.discourse-cdn.com/brewersassociation/user_avatar/forum.homebrewersassociation.org/denny/32/13092_2.png) [@denny](https://forum.homebrewersassociation.org/u/denny)\ **Post date:** [April 12, 2016, 8:32pm UTC](https://forum.homebrewersassociation.org/t/confessions-of-a-yeast-abuser/22946/36 "2016-04-12T20:32:58Z")
> [@charles1968](#): > > There’s certainly no harm in trying to be consistent. I do wonder if it matters as much as people claim though. **Yeast multiply until they’ve consumed all the sugar and then drop out. It happens every time, however many you start with**. I haven’t seen any compelling evidence that the starting number affects flavour, but I accept that it’s possible. Ya know, Charles, I was about to say I agreed with you until the bolded part.  I can’t agree with that.  If it was true, you’d only need to pitch a single yeast cell.  I think consistency of results is a good thing and it’s what I aim for.  But I’ve also found that you have a lot of leeway in the constituent parts that make up the result you want. ---
**Author:** ![charles1968](https://avatars.discourse-cdn.com/v4/letter/c/9dc877/32.png) [@charles1968](https://forum.homebrewersassociation.org/u/charles1968)\ **Post date:** [April 12, 2016, 8:47pm UTC](https://forum.homebrewersassociation.org/t/confessions-of-a-yeast-abuser/22946/37 "2016-04-12T20:47:15Z")
> [@klickitat\_jim](#): > > Proof that sometimes a little info = worrying about nothing. Yes I think I tend to overthink everything and I suspect other brewers do too, but maybe overthinking is part of the fun. ---
**Author:** ![system](https://us1.discourse-cdn.com/brewersassociation/original/1X/f1a2211dcb353b921ed70873794a31db2031eccc.png) [@system](https://forum.homebrewersassociation.org/u/system)\ **Post date:** [April 12, 2016, 8:49pm UTC](https://forum.homebrewersassociation.org/t/confessions-of-a-yeast-abuser/22946/38 "2016-04-12T20:49:23Z")
> [@charles1968](#): > > > [@klickitat\_jim](#): > > > > Proof that sometimes a little info = worrying about nothing. > > Yes I think I tend to overthink everything and I suspect other brewers do too, but maybe overthinking is part of the fun. I’m an engineer. I can’t get anything done unless I’ve invested at least 4 hours into overthinking it. ---
**Author:** ![denny](https://sea1.discourse-cdn.com/brewersassociation/user_avatar/forum.homebrewersassociation.org/denny/32/13092_2.png) [@denny](https://forum.homebrewersassociation.org/u/denny)\ **Post date:** [April 12, 2016, 8:58pm UTC](https://forum.homebrewersassociation.org/t/confessions-of-a-yeast-abuser/22946/39 "2016-04-12T20:58:00Z")
> [@charles1968](#): > > > [@klickitat\_jim](#): > > > > Proof that sometimes a little info = worrying about nothing. > > Yes I think I tend to overthink everything and I suspect other brewers do too, but maybe overthinking is part of the fun. I used to overthink things, than with experience I found that there are so many things that just don’t matter, or matter only in a general sense.  Pragmatism became my rule and it’s served me well.  But this is a hobby and if you enjoy the overthinking part, be my guest.  Personally, I have other things to expend my brain on! ---
**Author:** ![charles1968](https://avatars.discourse-cdn.com/v4/letter/c/9dc877/32.png) [@charles1968](https://forum.homebrewersassociation.org/u/charles1968)\ **Post date:** [April 12, 2016, 8:59pm UTC](https://forum.homebrewersassociation.org/t/confessions-of-a-yeast-abuser/22946/40 "2016-04-12T20:59:05Z")
> [@denny](#): > > Ya know, Charles, I was about to say I agreed with you until the bolded part.  I can’t agree with that.  If it was true, you’d only need to pitch a single yeast cell. That’s where you start needing laboratory techniques - isolate a single cell on a plate and step up, keeping everything completely sterile. Possible but not a standard homebrewing technique and not very quick. If you think of wort as a battleground in which all sorts of unseen microbes compete, then pitching a healthy population that gives yeast a headstart over bacteria or wild yeast makes perfect sense. A lag of a week or so is too long - you want yeast to poison the wort with alcohol and acid quickly so bacteria don’t get a toehold. But as long as you pitch enough for that, I don’t think adding more makes any difference. I can’t think of a time underpitching has given me any problems. Even with lager. Actually, pitching rate is probably least important with lager (unless you’re a commercial brewery) as the low temp stops bacteria and nonlager yeast growing. [Previous page](https://forum.homebrewersassociation.org/t/confessions-of-a-yeast-abuser/22946.md?page=1) [Next page](https://forum.homebrewersassociation.org/t/confessions-of-a-yeast-abuser/22946.md?page=3)