# Help be interpret this **URL:** \ **Category:** Ingredients\ **Created:** [June 6, 2018, 10:12pm UTC](https://forum.homebrewersassociation.org/t/help-be-interpret-this/27589 "2018-06-06T22:12:50Z")\ **Posts on this page:** 7\ **Page:** 2
**Author:** ![system](https://us1.discourse-cdn.com/brewersassociation/original/1X/f1a2211dcb353b921ed70873794a31db2031eccc.png) [@system](https://forum.homebrewersassociation.org/u/system)\ **Post date:** [June 8, 2018, 1:41am UTC](https://forum.homebrewersassociation.org/t/help-be-interpret-this/27589/21 "2018-06-08T01:41:31Z")
> [@klickitat\_jim](#): > > And maybe not… > Pitching 1 smack pack, active starters, to any ale I’ve done so far from 1.050 to 1.110, with numerous yeasts from American to English, I don’t find any beer “estery” > > One constant I find in home brewing. We read things and therefore they are so, even though we can’t make it happen at home. I really only pay attention to the science when known ester and higher alcohol producers like Belgian yeast is concerned. There I see results when I play with the levers. ---
**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:** [June 8, 2018, 1:56am UTC](https://forum.homebrewersassociation.org/t/help-be-interpret-this/27589/22 "2018-06-08T01:56:36Z")
I think Belgian yeasts play by different rules, not just than other ales or lagers, but sometimes different than other Belgians ---
**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:** [June 8, 2018, 2:01am UTC](https://forum.homebrewersassociation.org/t/help-be-interpret-this/27589/23 "2018-06-08T02:01:18Z")
If it were up to me to classify yeast, it wiuld be Ale, Lager, Hybrid, Belgian, and Wild ---
**Author:** ![joelv](https://avatars.discourse-cdn.com/v4/letter/j/43a26b/32.png) [@joelv](https://forum.homebrewersassociation.org/u/joelv)\ **Post date:** [June 9, 2018, 3:42pm UTC](https://forum.homebrewersassociation.org/t/help-be-interpret-this/27589/24 "2018-06-09T15:42:40Z")
You have ---
**Author:** ![Robertestein05\_gmail.com](https://avatars.discourse-cdn.com/v4/letter/r/c4cdca/32.png) [@Robertestein05\_gmail.com](https://forum.homebrewersassociation.org/u/Robertestein05_gmail.com)\ **Post date:** [June 9, 2018, 7:47pm UTC](https://forum.homebrewersassociation.org/t/help-be-interpret-this/27589/25 "2018-06-09T19:47:58Z")
> [@klickitat\_jim](#): > > If it were up to me to classify yeast, it wiuld be Ale, Lager, Hybrid, Belgian, and Wild And if it were up to me, those  classifications would ignore genotype.  And top/bottom behavior and much else related to phenotype.  Just, what does the beer it makes taste like?  Clean, fruity, funky…?  That’s how I’d classify  beer itself.  What it’s like, not how it’s made.  And if you can manipulate the same yeast to get different characters in the beer, hmm, things get even simpler.  Unless you’re all OCD about taxonomy. ---
**Author:** ![wbaar2](https://avatars.discourse-cdn.com/v4/letter/w/977dab/32.png) [@wbaar2](https://forum.homebrewersassociation.org/u/wbaar2)\ **Post date:** [June 12, 2018, 11:18pm UTC](https://forum.homebrewersassociation.org/t/help-be-interpret-this/27589/26 "2018-06-12T23:18:55Z")
Really interesting to read this with regards to Lars Garshol’s post on using Kveik. Probably need to read through both to really get it, but he recommended underpitching to suppress esters in kveik. [http://www.garshol.priv.no/blog/393.html](http://www.garshol.priv.no/blog/393.html) ---
**Author:** ![Robertestein05\_gmail.com](https://avatars.discourse-cdn.com/v4/letter/r/c4cdca/32.png) [@Robertestein05\_gmail.com](https://forum.homebrewersassociation.org/u/Robertestein05_gmail.com)\ **Post date:** [March 12, 2019, 7:42pm UTC](https://forum.homebrewersassociation.org/t/help-be-interpret-this/27589/27 "2019-03-12T19:42:29Z")
> [@denny](#): > > Back in 2003, the Homebrew Digest ran “A Fortnight of Yeast”, where you could ask questions of Dr. Clayton Cone, head of Lallemand and inventor of Fermaid K.  Here’s the question I asked and Dr. Cone’s response… > > "Dr. Cone, >   First, thank you so much for giving us some of your time. >   My question concerns yeast growth as it relates to flavors in beer.  I > have read several articles mentioning that yeast growth is important to > flavor production in beer, and that the amount of yeast growth is related to > the amount of yeast pitched.  My own completely unscientific experiments > have > lead  me to believe that I produce more "interesting’ beers when I, for > instance, repitch only part of the yeast slurry from a previous batch > rather than the entire amount.  The conventional wisdom in the homebrew > world seems to be to use the entire previous slurry to produce short lag > times.  Is there a relationship between yeast growth and the flavors > produced in beer?  Is it better to pitch an entire previous yeast slurry, > or is there a benefit to using a large, but not entire, amount of > slurry?  I apologize for the vagueness of the question, but I have no way > to quantify the exact amounts I’ve been using.  It’s simply either “all” or > “part”. >   Thank you again. > Denny Conn > > Denny Conn, >   Ester and other flavor component production or synthesis is a complex > subject because there are so many variables taking place at the same time. >   You are right, ester production is related to yeast growth but not in the > way you might think. The key element to yeast growth and ester production is > acyl Co-A. It is necessary for both yeast growth and ester production.  When > it is busy with yeast growth, during the early part of the fermentation, it > is not available for ester production.  Ester production is directly related > to biomass production. Everything that increases biomass production > (intensive aeration, sufficient amount of unsaturated fatty acids, > stirring) decreases ester production. The more biomass that is produced the > more Co-enzyme A is used and therefore not available for ester production. > Anything that inhibits or slows down yeast growth usually causes an increase > in ester production: low nutrient, low O2.  It has been noted that a drop in > available O2 from 8 ppm down to 3 ppm can cause a four fold increase in > esters. >   Stirring in normal gravity decreases ester production. Stirring in high > gravity increases ester production. CO2 pressure in early fermentation > decreases ester production.  Taller fermenters produce less esters than > short fermenters. High temperature early in fermentation decreases ester > production.  High temperature later in fermentation increases ester > production. Low pitching rate can result in less esters. >   There are other flavor components such as higher alcohol that have there > own > set of variables. Stirring increases production of higher alcohols.  CO2 > pressure does not effect the production of alcohol. Amino acid levels in the > wort effect the production of higher alcohols.  Most of the higher alcohol > is produced during the growth phase (exponential phase) of the yeast. >   I am sure that there are many other variables.  I am also sure that there > are beer makers that have experienced the very opposite with each of the > variables. > > Pitching rates depend on several factors: >   (1) The speed in which you wish the fermentation to take place.  Some > professional brew master are in more of a hurry than others; desired beer > style, shortage of fermenter space.  Pitching rates would vary as a means to > increase or decrease the total fermentation time. 10 X 10/6th cell > population for normal fermentation rates.  20 X 10/6th or more for a quick > turn around. >   (2) Temperature control.  If lack of refrigeration is a problem, the > fermentation needs to be spread out over a longer period  by pitching with > less yeast. >   (3) Health of the pitching yeast. If the pitching yeast has not been > stored > under ideal conditions (4C for less than one week) then larger pitching rate > must be done to compensate for the deteriorate of the yeast.  Increased > pitching rates has its limits in trying to compensate for poor storage > conditions. >   (4) When all other variables are under control you can use variations in > pitching rates to achieve certain flavor profile that are of interest to > you. >   Conventional wisdom regarding pitching rate can lead to problems.  During > each fermentation cycle the yeast will increase in size about three times, > so if you use all the yeast from the previous batch you will soon be > pitching with a huge amount of yeast.  Professional brewers usually re-pitch > with about 25% of the yeast from the previous batch. >   Proper handling of the yeast during storage (4C and \<7 days) will > minimize > any problem with long lag phase. Start with a fresh culture of yeast after > about five recycles for bacteria control and or after 10 - 15 cycles for > genetic drift purposes. >   There are many who will say that they are proud of the fact that they > have > used the same yeast after over 100 cycles.  More power to them. I wish that > I could explain their luck. Good practices suggest frequent renewal with a > fresh culture is a good policy. >   Thank you for your very good question. > > Clayton Cone" > > OK, so I’ve always taken that to mean that pitching “too much” yeast means that there is less biomass production and consequently more esters.  That’s pretty much the opposite of the conventional wisdom, as MANY people have pointed out to me over the years.  So, I want to know how you interpret this.  Am I right?  Or am I totally missing something that confirms the conventional wisdom? Don’t really mean to raise a zombie thread,  but I remembered this and came back to read it through in context of my experiments and research in pressurized fermentation.    Pressure early on is held to suppress yeast growth, which Dr. Cone suggests should increase esters, while reduction of ester production is a primary goal of pressure fermentation.  Dr. Cone, nonetheless, says that pressure early on does suppress ester formation.  There seems to be some tension here.  Further, research seems to indicate that it is pressure later in fermentation that somehow suppresses ester formation. Perhaps this is connected with increased yeast growth if pressure is not applied early, I don’t know.  Then what is the mechanism  of ester formation after the log phase that pressure is suppressing? I still don’t know what any of this means,  but find it interesting and thought the evidence from pressure fermentation should be thrown on the pile. 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