Homebrewers Association | AHA Forum

General Category => Yeast and Fermentation => Topic started by: wmsouthworth on November 09, 2015, 02:39:30 pm

Title: Banana ester in my lager after diacetyl rest
Post by: wmsouthworth on November 09, 2015, 02:39:30 pm
Hello,

I just got back into brewing after a ten year break. I have brewed some tasty ales in the last couple of months, so I tried my hand at a lager. I just finished the Diacetyl rest and suddenly my box freezer smells like bananas. Will this go away during lagering? I used WLP830 German lager yeast, a 2 liter starter in 5 gallons. Oxygenated with a difussion stone. Fermented at 52-54 degrees F. Then a diacetyl rest for 3 days at 55-57 degrees. Any hope for this beer?
Title: Re: Banana ester in my lager after diacetyl rest
Post by: blatz on November 09, 2015, 02:49:08 pm
sounds like underpitching.

your starter, is small by a factor of about 3-4 if you assume extremely fresh yeast.

larger starter, stir plated starter or use S. Cerevisae's recommended method of a 'shaken not stirred starter'.

I am pretty certain that ester won't ever fully exit the beer, although it may weaken over time to the point of being at least enjoyable.

btw - its still young, and it may just be the off smells of fermentation. 
Title: Re: Banana ester in my lager after diacetyl rest
Post by: wmsouthworth on November 09, 2015, 03:00:39 pm
sounds like underpitching.

your starter, is small by a factor of about 3-4 if you assume extremely fresh yeast.

larger starter, stir plated starter or use S. Cerevisae's recommended method of a 'shaken not stirred starter'.

I am pretty certain that ester won't ever fully exit the beer, although it may weaken over time to the point of being at least enjoyable.

btw - its still young, and it may just be the off smells of fermentation.

Thanks for the info. Next time I will use a much larger starter. I'm going to lager it and see what happens, but I don't have much of hope.
Title: Re: Banana ester in my lager after diacetyl rest
Post by: S. cerevisiae on November 09, 2015, 05:49:37 pm
A 2L starter in five gallons is not underpitching by any stretch of the imagination.  That's a roughly a 10-to-1 step.  My bet is on wort composition.  Banana is the ester known as isoamyl acetate, which is formed via a condensation reaction between isoamyl alcohol (a.k.a. isopentanol) and acetic acid.

C5H12OH + CH3COOH  → C7H14O2 + H2O

The reaction shown above reads isoamyl alcohol plus acetic acid produces isoamyl acetate plus water.   What this reaction means in layman's terms is that your fermentation generated isoamyl alcohol, and there was acetic acid available with which to form isoamyl acetate.  Acidic acid comes from acetyl-CoA.  We know that higher alcohol (isoamyl alcohol is a higher alcohol) production increases with biomass growth; however, so does acetyl-CoA utilization.  On the other hand, overpitching results in elevated acetyl-CoA and lower higher alcohol production.  This batch was neither overpitched nor underpitched, which means that something else went wrong.   What was the original gravity?  What was the wort composition?  How much trub did you carry over from the kettle?
 

Title: Re: Banana ester in my lager after diacetyl rest
Post by: wmsouthworth on November 09, 2015, 06:08:04 pm
A 2L starter in five gallons is not underpitching by any stretch of the imagination.  That's a roughly a 10-to-1 step.  My bet is on wort composition.  Banana is the ester known as isoamyl acetate, which is formed via a condensation reaction between isoamyl alcohol (a.k.a. isopentanol) and acetic acid.

C5H12OH + CH3COOH  → C7H14O2 + H2O

The reaction shown above reads isoamyl alcohol plus acetic acid produces isoamyl acetate plus water.   What this reaction means in layman's terms is that your fermentation generated isoamyl alcohol, and there was acetic acid available with which to form isoamyl alcohol.  Acidic acid comes from acetyl-CoA.  We know that higher alcohol (isoamyl alcohol is a higher alcohol) production increases with biomass growth; however, so does acetyl-CoA utilization.  On the other hand, overpitching results in elevated acetyl-CoA lower and lower higher alcohol production.  This batch was neither overpitched nor underpitched, which means that something else went wrong.   What was the original gravity?  What was the wort composition?  How much trub did you carry over from the kettle?
 

The original gravity was 1.051, it was a extract brew, 100% pilsner liquid malt extract from morebeer. I racked off the trub after letting it settle for 3 hours. I did pitch at 60 degrees which I now know is not good. The other thing I now know I did wrong is I added all of wort from the starter rather than pouring of most off the liquid.
Title: Re: Banana ester in my lager after diacetyl rest
Post by: duboman on November 09, 2015, 06:22:27 pm
I would pull it from the chamber and let it rise and finish and then lager, IMO, at less than 60 for only 3 days wasn't enough d-rest, mine usually get into the low-mid 60s and finish nicely.



Sent from my SAMSUNG-SM-G920A using Tapatalk

Title: Re: Banana ester in my lager after diacetyl rest
Post by: wmsouthworth on November 09, 2015, 06:53:39 pm
I would pull it from the chamber and let it rise and finish and then lager, IMO, at less than 60 for only 3 days wasn't enough d-rest, mine usually get into the low-mid 60s and finish nicely.



Sent from my SAMSUNG-SM-G920A using Tapatalk

I'll give that a try. Thanks.
Title: Banana ester in my lager after diacetyl rest
Post by: brulosopher on November 10, 2015, 06:20:23 am
A 2L starter in five gallons is not underpitching by any stretch of the imagination.  That's a roughly a 10-to-1 step.  My bet is on wort composition.  Banana is the ester known as isoamyl acetate, which is formed via a condensation reaction between isoamyl alcohol (a.k.a. isopentanol) and acetic acid.

C5H12OH + CH3COOH  → C7H14O2 + H2O

The reaction shown above reads isoamyl alcohol plus acetic acid produces isoamyl acetate plus water.   What this reaction means in layman's terms is that your fermentation generated isoamyl alcohol, and there was acetic acid available with which to form isoamyl alcohol.  Acidic acid comes from acetyl-CoA.  We know that higher alcohol (isoamyl alcohol is a higher alcohol) production increases with biomass growth; however, so does acetyl-CoA utilization.  On the other hand, overpitching results in elevated acetyl-CoA and lower higher alcohol production.  This batch was neither overpitched nor underpitched, which means that something else went wrong.   What was the original gravity?  What was the wort composition?  How much trub did you carry over from the kettle?

Yes! I was going to make some similar allusions without all the actual science to back it up.

This beer was not technically underpitched.
The original gravity was 1.051, it was a extract brew, 100% pilsner liquid malt extract from morebeer. I racked off the trub after letting it settle for 3 hours. I did pitch at 60 degrees which I now know is not good. The other thing I now know I did wrong is I added all of wort from the starter rather than pouring of most off the liquid.

I'm doubtful the starter beer had any lasting impact on the character of your beer. I have a more formal xBmt planned, but in my experience, even 2L of starter pitched without decanting imparts little if any noticeable character.

If I had to guess, the beer is either too young and you're perceiving something other than isoamyl acetate, or you picked up a wild yeast at some point.
Title: Re: Banana ester in my lager after diacetyl rest
Post by: rabeb25 on November 10, 2015, 07:32:31 am
Was this beer by chance brewed via decoction?
Title: Re: Banana ester in my lager after diacetyl rest
Post by: blatz on November 10, 2015, 07:56:39 am
while I understand the science behind it, in practice, the only 2 times (of the more than 80 batches of lager i've made) that I've gotten the banana ester was early in my brewing when I pitched a single smackpack into a 5 gal batch and most recently, when I tried to use the shaken not stirred approach on a vienna.  after 5 weeks of lagering, i dumped the latter this weekend.

i've had a lot more success stepping up a stir plated starter and pitching in the ballpark of what the yeast calcs say.  may not be what is being touted these days, but it works well for me. 

Was this beer by chance brewed via decoction?

I think he said it was extract.
Title: Re: Banana ester in my lager after diacetyl rest
Post by: S. cerevisiae on November 10, 2015, 08:25:59 am
If I had to guess, the beer is either too young and you're perceiving something other than isoamyl acetate, or you picked up a wild yeast at some point.

The problem could be due to a wild yeast or bacteria infection, but it could also be due to a mislabeled vial of yeast.  It does happen from time to time.  The only thing that could rule out receiving a mislabeled vial of yeast is fermentation temperature.  However, then again, fermentation temperature would also rule out wild microflora, which leads us back to wort composition, complete lack of trub, and/or dissolved O2 concentration.

Title: Re: Banana ester in my lager after diacetyl rest
Post by: S. cerevisiae on November 10, 2015, 08:30:04 am
while I understand the science behind it, in practice, the only 2 times (of the more than 80 batches of lager i've made) that I've gotten the banana ester was early in my brewing when I pitched a single smackpack into a 5 gal batch and most recently, when I tried to use the shaken not stirred approach on a vienna.  after 5 weeks of lagering, i dumped the latter this weekend.

Were you the one who attempted to make a large shaken, not stirred starter in not much larger flask?  Or was that Jeffy?   I have never obtained banana ester using the technique.  The only way to get banana ester with underpitching is coupling underpitching with underaeration. 
Title: Re: Banana ester in my lager after diacetyl rest
Post by: S. cerevisiae on November 10, 2015, 08:37:24 am
while I understand the science behind it, in practice, the only 2 times (of the more than 80 batches of lager i've made) that I've gotten the banana ester was early in my brewing when I pitched a single smackpack into a 5 gal batch and most recently, when I tried to use the shaken not stirred approach on a vienna.  after 5 weeks of lagering, i dumped the latter this weekend.

Was the posting linked below that batch?  If so, that procedure is not "Shaken, not stirred."

https://www.homebrewersassociation.org/forum/index.php?topic=24308.msg309727#msg309727
Title: Re: Banana ester in my lager after diacetyl rest
Post by: blatz on November 10, 2015, 08:48:30 am
No that was the batch previous to the vienna, a pils with mandarina.  That one turned out excellent for me.

For my vienna, I used 2 fresh vials of 830 in 2L 1.040 in a 5L flask.

It took an unusual amount of time to show signs of airlock activity, north of 40 hours (for comparison - the batch you linked I believe was showing signs in around 15 hours.  Perhaps something else came to the party, I'm not sure.

I may try the method again, albeit with a blast of pure O2 rather than shaking.  But I admitted gunshy after having dumped the last batch and having had a lot of success with my "outdated" methods.
Title: Re: Banana ester in my lager after diacetyl rest
Post by: jeffy on November 10, 2015, 11:02:31 am
while I understand the science behind it, in practice, the only 2 times (of the more than 80 batches of lager i've made) that I've gotten the banana ester was early in my brewing when I pitched a single smackpack into a 5 gal batch and most recently, when I tried to use the shaken not stirred approach on a vienna.  after 5 weeks of lagering, i dumped the latter this weekend.

Were you the one who attempted to make a large shaken, not stirred starter in not much larger flask?  Or was that Jeffy?   I have never obtained banana ester using the technique.  The only way to get banana ester with underpitching is coupling underpitching with underaeration.

That was me, with a witbier.  No off flavors, but less than satisfactory attenuation.
Title: Re: Banana ester in my lager after diacetyl rest
Post by: S. cerevisiae on November 10, 2015, 11:44:43 am
For my vienna, I used 2 fresh vials of 830 in 2L 1.040 in a 5L flask.

I have stated many times that the vessel has to be at least four times the volume of the medium, which means that a 2L starter requires an 8L or larger vessel. 

https://www.homebrewersassociation.org/forum/index.php?topic=24447.15

https://www.homebrewersassociation.org/forum/index.php?topic=24447.msg311561#msg311561


Now, add in the fact than an Erlenmeyer flask is a less than optimal choice for a shaken, not stirred starter due to its geometry, and one is pretty much ensured to be underwhelmed with the results. The best geometry for a shaken, not stirred starter is a cylinder where the height-to-diameter ratio is no more than 2:1. Additionally, while it does not hurt to pitch 2 vials of yeast into 2L of wort, only one is needed.  Pitching two vials instead of one does not buy one much in the grand scheme of things.

Title: Re: Banana ester in my lager after diacetyl rest
Post by: majorvices on November 10, 2015, 07:15:36 pm
A 2L starter in five gallons is not underpitching by any stretch of the imagination.  That's a roughly a 10-to-1 step.  My bet is on wort composition.  Banana is the ester known as isoamyl acetate, which is formed via a condensation reaction between isoamyl alcohol (a.k.a. isopentanol) and acetic acid.

C5H12OH + CH3COOH  → C7H14O2 + H2O

The reaction shown above reads isoamyl alcohol plus acetic acid produces isoamyl acetate plus water.   What this reaction means in layman's terms is that your fermentation generated isoamyl alcohol, and there was acetic acid available with which to form isoamyl alcohol.  Acidic acid comes from acetyl-CoA.  We know that higher alcohol (isoamyl alcohol is a higher alcohol) production increases with biomass growth; however, so does acetyl-CoA utilization.  On the other hand, overpitching results in elevated acetyl-CoA lower and lower higher alcohol production.  This batch was neither overpitched nor underpitched, which means that something else went wrong.   What was the original gravity?  What was the wort composition?  How much trub did you carry over from the kettle?
 

The original gravity was 1.051, it was a extract brew, 100% pilsner liquid malt extract from morebeer. I racked off the trub after letting it settle for 3 hours. I did pitch at 60 degrees which I now know is not good. The other thing I now know I did wrong is I added all of wort from the starter rather than pouring of most off the liquid.

That right there is you problem.
Title: Re: Banana ester in my lager after diacetyl rest
Post by: chumley on November 10, 2015, 09:10:02 pm
majorvices hits it!

I unfortunately started my last lager at 65°F.  I discovered that one cannot rely on dial thermometers stuck into kettles when a wet horizontal snow is falling at a rapid clip.  It is still fermenting, but I will be curious to see if I get a banana ester from fermenting too warm.  It is at 48°F now, but the damage may have been already done.

I once tried using 34/70 at 62°F and wound up with fruitcake pilsner.
Title: Re: Banana ester in my lager after diacetyl rest
Post by: wmsouthworth on November 10, 2015, 09:11:33 pm
If I had to guess, the beer is either too young and you're perceiving something other than isoamyl acetate, or you picked up a wild yeast at some point.

The problem could be due to a wild yeast or bacteria infection, but it could also be due to a mislabeled vial of yeast.  It does happen from time to time.  The only thing that could rule out receiving a mislabeled vial of yeast is fermentation temperature.  However, then again, fermentation temperature would also rule out wild microflora, which leads us back to wort composition, complete lack of trub, and/or dissolved O2 concentration.

There was a complete lack of Trub, the wort was completely clear.  The beer had sulfur notes during primary and started to smell of banana when I raised the temp at the end. Maybe lack of trub was the problem? There was plenty of oxygen in the wort prior to pitching.  I am serious about sanitation, but we all make mistakes. If the yeast was possibly mislabeled what would it be? what produces banana ester at 50F ?
Title: Re: Banana ester in my lager after diacetyl rest
Post by: majorvices on November 11, 2015, 06:09:28 am
If I had to guess, the beer is either too young and you're perceiving something other than isoamyl acetate, or you picked up a wild yeast at some point.

The problem could be due to a wild yeast or bacteria infection, but it could also be due to a mislabeled vial of yeast.  It does happen from time to time.  The only thing that could rule out receiving a mislabeled vial of yeast is fermentation temperature.  However, then again, fermentation temperature would also rule out wild microflora, which leads us back to wort composition, complete lack of trub, and/or dissolved O2 concentration.

There was a complete lack of Trub, the wort was completely clear.  The beer had sulfur notes during primary and started to smell of banana when I raised the temp at the end. Maybe lack of trub was the problem? There was plenty of oxygen in the wort prior to pitching.  I am serious about sanitation, but we all make mistakes. If the yeast was possibly mislabeled what would it be? what produces banana ester at 50F ?

A little trub is actually good for a beer. Too much may cause problems but I highly doubt this is your problem. Look, all due respect to our resident yeast expert, there is a very tried and true method to making great homebrew lagers. And it doesn't involve overcomplicating things.

If you are not using a stir plate, then you should start with a 4 liter starter. 2 vials per 4 L per 5 gallons of 1.050ish wort is not going to be too big. Aeration at the start will benifit greatly. Ferment you starter at room temp. When finished cold crash. Decant starter wort. Cool your wort all the way down to 46-48 degrees for pale lagers, 50-52 for dark lagers. Aerate 2Xs as much as you would for ales. Pitch yeast. Once fermentation is active hold temp at 48-50 for pale lagers and 50-52 for dark lagers for 48-72 hours. After this you may want to ramp the temp up a couple degrees or hold for as long as 5-7 days before ramping up to about 58 degrees (I go about 2 degrees a a day when I am ramping and I wait till the end of fermentation.)

Hold at 58 (or even as high as 62) for the remainder of fermentation. You will have a very clean, diacetyl and isoamyl-acetate free lager. I promise.
Title: Re: Banana ester in my lager after diacetyl rest
Post by: Wort-H.O.G. on November 11, 2015, 09:18:02 am
^^^^^ +1 to this. other than than non-stir plate part for me where im usually about 3L one vial stirred, everything else the same in my process.

great clean lagers will be the result.
Title: Re: Banana ester in my lager after diacetyl rest
Post by: blatz on November 11, 2015, 10:36:11 am
To clarify.  The OP I don't think used 2 vials - that was me commented on the shaken not stirred that I clearly did not follow directions on, shame on me.  10 gal batch thought I would double things :(

I follow Majorvices process almost exactly, having built up from 2-3 vials.

while I didn't realize he pitched at such a high temp, and I agree that is the culprit I also think had he pitched more yeast he may have had a better result.

Title: Re: Banana ester in my lager after diacetyl rest
Post by: Wort-H.O.G. on November 11, 2015, 10:41:50 am

To clarify.  The OP I don't think used 2 vials - that was me commented on the shaken not stirred that I clearly did not follow directions on, shame on me.  10 gal batch thought I would double things :(

I follow Majorvices process almost exactly, having built up from 2-3 vials.

while I didn't realize he pitched at such a high temp, and I agree that is the culprit I also think had he pitched more yeast he may have had a better result.

The same two things that killed me with lagers in my early/ first lagers Paul.


Sent from my iPhone using Tapatalk
Title: Re: Banana ester in my lager after diacetyl rest
Post by: S. cerevisiae on November 11, 2015, 12:45:25 pm
That right there is you problem.

That's not it.  I start every lager that I make at 16C/61F before dropping the temperature slowly to 13C/55F, and I never get isoamyl acetate.  There's zero need to ferment a lager below 13C. The use of Saccharomyces pastorianus in brewing is the result of selective pressure placed on mixed Saccharomyces pastorianus and Saccharomyces cerevisiae cultures at 13C/55F, which is the year-round temperature below the frost line. 
Title: Re: Banana ester in my lager after diacetyl rest
Post by: majorvices on November 11, 2015, 01:00:00 pm
The original gravity was 1.051, it was a extract brew, 100% pilsner liquid malt extract from morebeer. I racked off the trub after letting it settle for 3 hours. I did pitch at 60 degrees which I now know is not good. The other thing I now know I did wrong is I added all of wort from the starter rather than pouring of most off the liquid.

That right there is you problem.

That's not it.  I start every lager that I make at 16C/61F before dropping the temperature slowly to 13C/55F, and I never get isoamyl acetate.  There's zero need to ferment a lager below 13C. The use of Saccharomyces pastorianus in brewing is the result of selective pressure placed on mixed Saccharomyces pastorianus and Saccharomyces cerevisiae cultures at 13C/55F, which is the year-round temperature below the frost line.
[/quote]

I know that there are many folks who do use that method successfully, I am trying to give him a simple method that works for a great majority of us lagering brewing folks here on the forum. I have been brewing lagers for 15 years and have never gotten isoamyl acetate by pitching cold. I also brew commercial lagers that are distributed across two states using this method (though, at a much larger scale) and it is a tried an true method that works.

Mark, I'd love to have your deep understanding of microbiology and chemistry and I hope to hire a guy someday who has that knowledge but for homebrewers the method I have described works.
Title: Re: Banana ester in my lager after diacetyl rest
Post by: HoosierBrew on November 11, 2015, 01:04:41 pm
If you are not using a stir plate, then you should start with a 4 liter starter. 2 vials per 4 L per 5 gallons of 1.050ish wort is not going to be too big. Aeration at the start will benifit greatly. Ferment you starter at room temp. When finished cold crash. Decant starter wort. Cool your wort all the way down to 46-48 degrees for pale lagers, 50-52 for dark lagers. Aerate 2Xs as much as you would for ales. Pitch yeast. Once fermentation is active hold temp at 48-50 for pale lagers and 50-52 for dark lagers for 48-72 hours. After this you may want to ramp the temp up a couple degrees or hold for as long as 5-7 days before ramping up to about 58 degrees (I go about 2 degrees a a day when I am ramping and I wait till the end of fermentation.)

Hold at 58 (or even as high as 62) for the remainder of fermentation. You will have a very clean, diacetyl and isoamyl-acetate free lager. I promise.


That's pretty much exactly what I'm doing now for lagers and it's the best, most consistent method I've used, by far.  No diacetyl or other off flavors/aromas.
Title: Re: Banana ester in my lager after diacetyl rest
Post by: ynotbrusum on November 11, 2015, 01:47:15 pm
My observances on a couple issues raised in this thread:

My last Helles was a 10 gallon batch - the starter was the first gallon run off from the kettle into a 3 gallon better bottle with solid stopper (silicone o-ring tight), shaken like I needed bail from a brother-in-law who owed me money, pitched two packs of 2038 at room temperature, held to high krausen and pitched into the chilled and aerated wort about 7-8 hours later (after return from a neighborhood gathering).  It was off and running/roaring like an ale when I checked in the following morning.

As to starting warm and dropping after fermentation becomes active - I know a solid award winning lager home Brewer who does it this way and we just agree to enjoy each other's beers without challenging process.  (BTW his day job allows me to purchase his pro wares at the local beer store - he is Siebel taught and knowledgable).
Title: Re: Banana ester in my lager after diacetyl rest
Post by: S. cerevisiae on November 11, 2015, 01:52:03 pm
I know that there are many folks who do use that method successfully, I am trying to give him a simple method that works for a great majority of us lagering brewing folks here on the forum. I have been brewing lagers for 15 years and have never gotten isoamyl acetate by pitching cold. I also brew commercial lagers that are distributed across two states using this method (though, at a much larger scale) and it is a tried an true method that works.

Mark, I'd love to have your deep understanding of microbiology and chemistry and I hope to hire a guy someday who has that knowledge but for homebrewers the method I have described works.

It's just that telling a home brewer that he/she needs to pitch 2 vials of yeast into 4 liters of wort for a 5-gallon batch is extreme overkill.  That is a 5-to-1 step, which is higher than I use in an aseptic setting when growing yeast from a slant.  There is a lot more that can go wrong when working with a culture that small than working with one or two cultures that started out as 100B cells.  The difference between pitching one vial and pitching two vials is 90 minutes of propagation time at room temperature, that is, as long as there is enough carbon, volume, and dissolved O2 to support the growth.


The number one mistake that home brewers make when propagating Saccharomyces pastorianus (a.k.a. lager yeast) is propagating at lager fermentation temperature.  Low temperatures suppress metabolism, and anything that suppresses metabolism suppresses biomass growth.  All starters should be propagated at room temperature.

For those who want to understand more about yeast growth, please take a minute to read the following entry from my blog: www.experimentalbrew.com/blogs/saccharomyces/yeast-cultures-are-nuclear-weapons

Title: Re: Banana ester in my lager after diacetyl rest
Post by: majorvices on November 11, 2015, 01:52:34 pm
My observances on a couple issues raised in this thread:

My last Helles was a 10 gallon batch - the starter was the first gallon run off from the kettle into a 3 gallon better bottle with solid stopper (silicone o-ring tight), shaken like I needed bail from a brother-in-law who owed me money, pitched two packs of 2038 at room temperature, held to high krausen and pitched into the chilled and aerated wort about 7-8 hours later (after return from a neighborhood gathering).  It was off and running/roaring like an ale when I checked in the following morning.

As to starting warm and dropping after fermentation becomes active - I know a solid award winning lager home Brewer who does it this way and we just agree to enjoy each other's beers without challenging process.  (BTW his day job allows me to purchase his pro wares at the local beer store - he is Siebel taught and knowledgable).

It's like I tell the brewers who work under me. There isn't necessarily a right way to do things, but there are certainly wrong ways. Whatever way works is the best way. That said, when you are doing something that isn't working, and someone suggests a way that does work for lots of people, you might want to try it!
Title: Re: Banana ester in my lager after diacetyl rest
Post by: S. cerevisiae on November 11, 2015, 01:55:29 pm
shaken like I needed bail from a brother-in-law who owed me money

ROTFL!  May I use that one?
Title: Re: Banana ester in my lager after diacetyl rest
Post by: majorvices on November 11, 2015, 02:06:00 pm
I know that there are many folks who do use that method successfully, I am trying to give him a simple method that works for a great majority of us lagering brewing folks here on the forum. I have been brewing lagers for 15 years and have never gotten isoamyl acetate by pitching cold. I also brew commercial lagers that are distributed across two states using this method (though, at a much larger scale) and it is a tried an true method that works.

Mark, I'd love to have your deep understanding of microbiology and chemistry and I hope to hire a guy someday who has that knowledge but for homebrewers the method I have described works.

It's just that telling a home brewer that he/she needs to pitch 2 vials of yeast into 4 liters of wort for a 5-gallon batch is extreme overkill.  That is a 5-to-1 step, which is higher than I use in an aseptic setting when growing yeast from a slant.  There is a lot more that can go wrong when working with a culture that small than working with one or two cultures that started out as 100B cells.  The difference between pitching one vial and pitching two vials is 90 minutes of propagation time at room temperature, that is, as long as there is enough carbon, volume, and dissolved O2 to support the growth.


The number one mistake that home brewers make when propagating Saccharomyces pastorianus (a.k.a. lager yeast) is propagating at lager fermentation temperature.  Low temperatures suppress metabolism, and anything that suppresses metabolism suppresses biomass growth.  All starters should be propagated at room temperature.

For those who want to understand more about yeast growth, please take a minute to read the following entry from my blog: www.experimentalbrew.com/blogs/saccharomyces/yeast-cultures-are-nuclear-weapons

But, wouldn't the amount of vial he or she needs to be pitched into a starter be dependent on the viability of the yeast in the vials? As a commercial brewer I am lucky enough to know that my pitch when I receive it overnighted from WYEAST is near 100% viable. With vials and smack packs there is now way to tell exactly how viable the yeast is in even a 4-6 week old pitch of yeast.
Title: Re: Banana ester in my lager after diacetyl rest
Post by: ynotbrusum on November 11, 2015, 02:28:49 pm
shaken like I needed bail from a brother-in-law who owed me money

ROTFL!  May I use that one?

Please do - visualization in this instance provided extra vigor!
Title: Re: Banana ester in my lager after diacetyl rest
Post by: wmsouthworth on November 12, 2015, 10:49:02 pm
Just want to thanks the folks who responded to my questions. After reading all the responses I think I will stick with Ales for a while before trying another lager. I'm trying to keep life simple. I'm thinking about using a clean tasting ale yeast (like 1056) and making ales with hops typically used in lager, and the doing extended cold conditioning in the bottle. Just play around with it and see what happens.
Title: Re: Banana ester in my lager after diacetyl rest
Post by: RPIScotty on November 13, 2015, 04:37:52 am
I know that there are many folks who do use that method successfully, I am trying to give him a simple method that works for a great majority of us lagering brewing folks here on the forum. I have been brewing lagers for 15 years and have never gotten isoamyl acetate by pitching cold. I also brew commercial lagers that are distributed across two states using this method (though, at a much larger scale) and it is a tried an true method that works.

Mark, I'd love to have your deep understanding of microbiology and chemistry and I hope to hire a guy someday who has that knowledge but for homebrewers the method I have described works.

It's just that telling a home brewer that he/she needs to pitch 2 vials of yeast into 4 liters of wort for a 5-gallon batch is extreme overkill.  That is a 5-to-1 step, which is higher than I use in an aseptic setting when growing yeast from a slant.  There is a lot more that can go wrong when working with a culture that small than working with one or two cultures that started out as 100B cells.  The difference between pitching one vial and pitching two vials is 90 minutes of propagation time at room temperature, that is, as long as there is enough carbon, volume, and dissolved O2 to support the growth.


The number one mistake that home brewers make when propagating Saccharomyces pastorianus (a.k.a. lager yeast) is propagating at lager fermentation temperature.  Low temperatures suppress metabolism, and anything that suppresses metabolism suppresses biomass growth.  All starters should be propagated at room temperature.

For those who want to understand more about yeast growth, please take a minute to read the following entry from my blog: www.experimentalbrew.com/blogs/saccharomyces/yeast-cultures-are-nuclear-weapons

But, wouldn't the amount of vial he or she needs to be pitched into a starter be dependent on the viability of the yeast in the vials? As a commercial brewer I am lucky enough to know that my pitch when I receive it overnighted from WYEAST is near 100% viable. With vials and smack packs there is now way to tell exactly how viable the yeast is in even a 4-6 week old pitch of yeast.

The amount grown prior to pitching, if I have been following on with what Mark has been saying in the last few months, would be dependent on the starter medium size. The initial amount of cells would dictate the amount of time spent replicating to get there.
Title: Re: Banana ester in my lager after diacetyl rest
Post by: majorvices on November 13, 2015, 05:16:21 am
Just want to thanks the folks who responded to my questions. After reading all the responses I think I will stick with Ales for a while before trying another lager. I'm trying to keep life simple. I'm thinking about using a clean tasting ale yeast (like 1056) and making ales with hops typically used in lager, and the doing extended cold conditioning in the bottle. Just play around with it and see what happens.

It's too bad. Because this is exactly what happens when we try to make things too complicated. I have been brewing lagers in the manner I have stated above for over 15 years with fantastic results, and so have many others who have used similar methods on this forum. If you have temp control and the ability to make a decent size starter you can make fantastic lagers at home. It's simple, really. I feel bad that we tried to show you the forest but seems like the trees got in the way. Regardless, if you change your mind, try the method I proposed. It's simple and it works.
Title: Re: Banana ester in my lager after diacetyl rest
Post by: klickitat jim on November 13, 2015, 05:16:37 am
I know that there are many folks who do use that method successfully, I am trying to give him a simple method that works for a great majority of us lagering brewing folks here on the forum. I have been brewing lagers for 15 years and have never gotten isoamyl acetate by pitching cold. I also brew commercial lagers that are distributed across two states using this method (though, at a much larger scale) and it is a tried an true method that works.

Mark, I'd love to have your deep understanding of microbiology and chemistry and I hope to hire a guy someday who has that knowledge but for homebrewers the method I have described works.

It's just that telling a home brewer that he/she needs to pitch 2 vials of yeast into 4 liters of wort for a 5-gallon batch is extreme overkill.  That is a 5-to-1 step, which is higher than I use in an aseptic setting when growing yeast from a slant.  There is a lot more that can go wrong when working with a culture that small than working with one or two cultures that started out as 100B cells.  The difference between pitching one vial and pitching two vials is 90 minutes of propagation time at room temperature, that is, as long as there is enough carbon, volume, and dissolved O2 to support the growth.


The number one mistake that home brewers make when propagating Saccharomyces pastorianus (a.k.a. lager yeast) is propagating at lager fermentation temperature.  Low temperatures suppress metabolism, and anything that suppresses metabolism suppresses biomass growth.  All starters should be propagated at room temperature.

For those who want to understand more about yeast growth, please take a minute to read the following entry from my blog: www.experimentalbrew.com/blogs/saccharomyces/yeast-cultures-are-nuclear-weapons

But, wouldn't the amount of vial he or she needs to be pitched into a starter be dependent on the viability of the yeast in the vials? As a commercial brewer I am lucky enough to know that my pitch when I receive it overnighted from WYEAST is near 100% viable. With vials and smack packs there is now way to tell exactly how viable the yeast is in even a 4-6 week old pitch of yeast.

The amount grown prior to pitching, if I have been following on with what Mark has been saying in the last few months, would be dependent on the starter medium size. The initial amount of cells would dictate the amount of time spent replicating to get there.
Yup. 50% viability would mean an extra ~90 minutes. Though I think there may be some other complexities at play here. In other words, I don't think they go from awesome to dead with a flip of a switch.
Title: Re: Banana ester in my lager after diacetyl rest
Post by: narcout on November 13, 2015, 10:30:16 am
Just want to thanks the folks who responded to my questions. After reading all the responses I think I will stick with Ales for a while before trying another lager. I'm trying to keep life simple. I'm thinking about using a clean tasting ale yeast (like 1056) and making ales with hops typically used in lager, and the doing extended cold conditioning in the bottle. Just play around with it and see what happens.

I hope you will post an update once the beer is packaged and ready to drink. 

I'm curious to hear whether you even end up with any off flavors.
Title: Re: Banana ester in my lager after diacetyl rest
Post by: wmsouthworth on November 13, 2015, 12:21:24 pm
Just want to thanks the folks who responded to my questions. After reading all the responses I think I will stick with Ales for a while before trying another lager. I'm trying to keep life simple. I'm thinking about using a clean tasting ale yeast (like 1056) and making ales with hops typically used in lager, and the doing extended cold conditioning in the bottle. Just play around with it and see what happens.

I hope you will post an update once the beer is packaged and ready to drink. 

I'm curious to hear whether you even end up with any off flavors.

At the end of lagering I will give it a taste with my wife ( she has an excellent palate) and decide if it's worth bottling and will report back. I will be purchasing a stir plate before my next attempt, and shooting for a higher cell count, and pitching colder, and.......... :)
Title: Re: Banana ester in my lager after diacetyl rest
Post by: ynotbrusum on November 15, 2015, 05:30:03 pm
I bet it will be good.  The thing about pitching yeast, though, is the vitality of the yeast, as far as I understand it.  The number of cells is a factor, because the more cells, the more likely you have significant numbers of vital cells.  However, the greater the number of very healthy cells, the better the pitch.
Title: Re: Banana ester in my lager after diacetyl rest
Post by: wmsouthworth on December 27, 2015, 07:40:42 pm
I bet it will be good.  The thing about pitching yeast, though, is the vitality of the yeast, as far as I understand it.  The number of cells is a factor, because the more cells, the more likely you have significant numbers of vital cells.  However, the greater the number of very healthy cells, the better the pitch.

Well The banana ester or whatever is was is gone. I did let it come back to fermentation temp for a few days before tasting it. So your hunch was right, thankfully. Time to bottle. :D
Title: Re: Banana ester in my lager after diacetyl rest
Post by: narvin on December 27, 2015, 08:35:04 pm
Chilling lagers after pitching is going to be an extremely hard to replicate procedure, especially across different homebrew systems.  Your batch size, fermenter size/shape, and chilling power will all affect the cooling rate.  That doesn't even take into account that fermentation will progress at different rates because of things like pitching rate, yeast health, and aeration.

I'm sure it can be done, but it's not easy or foolproof.  So why recommend it to a new lager brewer?