Hunting the dreaded off-flavour.... marzipan.

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Beer666

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Which one do you mean? The biab method? How long are you boiling your wort?

I use a recirculating system with a bag. If i boil i sparge and if its raw i do a full volume mash. I generally boil for an hour or more as i have slow boil off rate. Raw beers only go up to 75c.
 
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Miraculix

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So I went back to biab for a few batches and the off flavour is gone. There is the slightest hint of it present directly after fermentation finished, but I am heavily sensitive to this particular almond flavour now and it is aging out in one or two weeks. I bet nobody else would actually notice it.

I'm happy with continuing full volume biab now, but if I wanna do high gravity batches, I'll need to get back to the classic mash ton because of volume issues of my small kettle.

I will try to limit the flow rate of the hose at the end of it by tying it together with a piece of wire. That way the hose should stay full of liquid all the time so there's no excessive oxigenation by partially filled hoses and the resulting inner turbulence.
 
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IslandLizard

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I read the whole thread, just not thoroughly.
Silicone hose were mentioned. But could it be from any vinyl tubing used in the system, moving wort to the fermenter, or when racking? Possibly more so when or after contact with hot liquids, who knows how much it lingers?

The other thing I've noticed the past year or so, is how our chlorinated tap water left in a (plastic) cup smells and tastes marzipan/almond-paste like.
 
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Miraculix

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I read the whole thread, just not thoroughly.
Silicone hose were mentioned. But could it be from any vinyl tubing used in the system, moving wort to the fermenter, or when racking? Possibly more so when or after contact with hot liquids, but who knows how much it lingers?

The other thing I've noticed the past year or so, is how our chlorinated tap water left in a (plastic) cup smells and tastes marzipan/almond-paste like.
Nope, no vinyl in the process. Chlorine is not an issue in Bremen, so that's also no possibility.

Maybe it's the tap of my mash bucket? It's literally like an aeration device in combination with the hose, which is way too big for the flow rate during the lauter.
 

IslandLizard

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Maybe it's the tap of my mash bucket? It's literally like an aeration device in combination with the hose, which is way too big for the flow rate during the lauter.
You may be on to something there. Hot side aeration...

I've been underletting the mash the past 2-3 years. It's really easy, as long as one includes a calculated or estimated mash tun heat loss. It's also easier to add some cold water or ice to bring it down a few degrees than trying to raise it in a non-heated mash tun (plastic cooler). ;)
 

TheMadKing

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So @Miraculix i just wanted to update you that I got Marzipan in my latest Scottish ale.

It has 2 major flaws that I can detect:

First it's hazy and astringent because I had my mash thickness way too low for a small grain bill and ended up over sparging (meaning my end of runnings gravity was way too low, close to 1.000 I think). So I got polyphenols from the malt resulting in permanent haze and slight astringency. But hey my mash efficiency was 93%! 😁

Second, I ran out of oxygen prior to brewing it and I pump my kettle directly into my conical resulting in very low aeration. So I had a SLOOOW and poor fermentation and I raised the temp to 73F trying to get it to finish. I used WY1318 in this batch, second pitch

The main off flavor definitely comes across as marzipan or artificial cherry, but the other day I was eating a piece of French bread and took a drink right after eating the bread, and bam... Ethyl acetate. Plain as day nail polish remover

After a few more sips my taste buds re-aclimated and it shifted back to marzipan.

So I submit low level (like barely at taste threshold) Ethyl acetate as a possible cause of this flavor. Maybe it's caused by an interaction between yeast and grain husk polyphenols?
 

Bilsch

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The other thing I've noticed the past year or so, is how our chlorinated tap water left in a (plastic) cup smells and tastes marzipan/almond-paste like.

Interesting. Toluene is converted to benzaldehyde (very almond smelling) by photochlorination.
Was your cup sitting in the sunlight?
Ever had your water lab checked for aromatic hydrocarbons?
 

IslandLizard

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Interesting. Toluene is converted to benzaldehyde (very almond smelling) by photochlorination.
Was your cup sitting in the sunlight?
Ever had your water lab checked for aromatic hydrocarbons?
Yeah, interesting...

No, those cups are typically on a counter they may indeed get some early morning direct/indirect sunlight, in Summer. Hmm, you may be on to something.
The weird almond-like scent/flavor is not always, just once in a while, and it's not chlorine.

I do smell/taste the chlorine, and the levels vary widely. Sometimes it can be really strong. Not anything like a pool though, I had one, I know what that's like.

Our county's water plant has their yearly quality reports online, with no significant aromatic molecule content. If any, it's very low ppb. But maybe there are a few spikes, that remain hidden.
The water source is from deep "private" wells with a rather large distribution area. A 10 inch mains goes up the main highway for 15-20 miles before it Ts off, serving our communities to the east.

No, I haven't sent out any samples for my own report.
I'm keeping a closer eye on it.
 

Bilsch

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Our county's water plant has their yearly quality reports online, with no significant aromatic molecule content. If any, it's very low ppb. But maybe there are a few spikes, that remain hidden.
The water source is from deep "private" wells with a rather large distribution area. A 10 inch mains goes up the main highway for 15-20 miles before it Ts off, serving our communities to the east.

I had to look tolulene up myself to see if it was a common contaminant in ground water and apparently it is anywhere industry, manufacturing, refineries etc have been for a long time. I know my industry used a metric **** ton over the years although it was consumed in the process so none was discarded.
 
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Miraculix

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I have just brewed a batch of dark mild. The last bottle did not fill up completely, about 1/3 was left empty and I placed it on the heater, to force bottle carbonation. Guess what..... full blown marzipan. I did not detect it directly out of the fermenter, so it hopefully is only this extra warm and oxidised bottle. Good example for what happens when thre is headspace.
 

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I have just brewed a batch of dark mild. The last bottle did not fill up completely, about 1/3 was left empty and I placed it on the heater, to force bottle carbonation. Guess what..... full blown marzipan. I did not detect it directly out of the fermenter, so it hopefully is only this extra warm and oxidised bottle. Good example for what happens when thre is headspace.
I believe my beers are all suffering the same thing yours are, but the flavor in mine is detectable after about 2 weeks in the keg as the initial hop aromas are declining (I mostly make hoppy styles). I wonder if you tasted this because of the high temps causing the yeast to make ethyl acetate, not necessarily oxidation (although seems like that would also be assured with high temps).

I'm interested in your ethyl acetate theory and I use Safale US-05 for every batch, fermenting between 63*F to 70*F to test the impact of different temps (forum posts claim cleaner ferment at higher temps). Recently I tried adding a campden tablet when I transferred to the keg because I too suspected oxidation, but the same flavor came through 2 weeks later... hence why I'm here looking for answers.

I just happened to make Edwort's Haus Pale Ale with US-05 but fermented lower at 59-60*F so I'm interested to see if the flavor appears there too, it's been in the keg 1 week so far (also with a Campden tablet) and no off flavor so far *all fingers and toes crossed*.

Have you made any progress since November? I saw you were dabbling with BIAB to avoid hot-side oxidation.
 
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Miraculix

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I believe my beers are all suffering the same thing yours are, but the flavor in mine is detectable after about 2 weeks in the keg as the initial hop aromas are declining (I mostly make hoppy styles). I wonder if you tasted this because of the high temps causing the yeast to make ethyl acetate, not necessarily oxidation (although seems like that would also be assured with high temps).

I'm interested in your ethyl acetate theory and I use Safale US-05 for every batch, fermenting between 63*F to 70*F to test the impact of different temps (forum posts claim cleaner ferment at higher temps). Recently I tried adding a campden tablet when I transferred to the keg because I too suspected oxidation, but the same flavor came through 2 weeks later... hence why I'm here looking for answers.

I just happened to make Edwort's Haus Pale Ale with US-05 but fermented lower at 59-60*F so I'm interested to see if the flavor appears there too, it's been in the keg 1 week so far (also with a Campden tablet) and no off flavor so far *all fingers and toes crossed*.

Have you made any progress since November? I saw you were dabbling with BIAB to avoid hot-side oxidation.
I actually solved it. Kind of...... Let's say, I solved it 80% :D

What I am doing now is adding vitamin c to the mash, prior to doughing in. I use about 4 g per 20 l of water. If I lower the amount of vitamin C, the almond flavour starts slowly to fade in again, depending on how much I lowered the amount of vitamin C. I am also trying the yeast oxygen scavenging technique with a pack of bread yeast and a few tablespooons of sugar 12h before brewing into the brewing water. I cannot really say if this does anything at all, because I also used the vitmain C, what I can tell thought is that the yeast oxygen scavenging alone seems to be not enough for me. it lowers the dissolved oxygen in the water, so why not.

More details:
 

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Interesting, sounds like LODO techniques! I was considering using 1/2 a Campden tablet in my water next time to try to purge chlorine, so maybe that'll have the same oxygen scavenging effect your Vitamin C has? Planning to make a Citra/Mosaic Hazy IPA in a few weeks so I'll definitely give this a try, thanks for the insight!

Out of curiosity, have you noticed any correlation with the use of specialty malts? I know some people hate Crystal malt but I end up using it in most batches since I've mostly brewed clones. Planning to use Maris Otter, 2-row, and flaked oats for this Hazy IPA to also try to rule out the specialty malt variable...

Edit: I've also tasted the mystery flavor in a two commercial beers but can't remember how old they were - 3 Floyd's Zombie Dust and Bell's 2 Hearted Ale. Given that those are world class beers I'm wondering if I'm just mistaking sweet malty flavors from specialty grain as a bad thing... but I don't taste it anywhere else!
 
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Miraculix

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Interesting, sounds like LODO techniques! I was considering using 1/2 a Campden tablet in my water next time to try to purge chlorine, so maybe that'll have the same oxygen scavenging effect your Vitamin C has? Planning to make a Citra/Mosaic Hazy IPA in a few weeks so I'll definitely give this a try, thanks for the insight!

Out of curiosity, have you noticed any correlation with the use of specialty malts? I know some people hate Crystal malt but I end up using it in most batches since I've mostly brewed clones. Planning to use Maris Otter, 2-row, and flaked oats for this Hazy IPA to also try to rule out the specialty malt variable...

Edit: I've also tasted the mystery flavor in a two commercial beers but can't remember how old they were - 3 Floyd's Zombie Dust and Bell's 2 Hearted Ale. Given that those are world class beers I'm wondering if I'm just mistaking sweet malty flavors from specialty grain as a bad thing... but I don't taste it anywhere else!
I had it with base malt only plenty of times, so in my case I can rule out the crystal malt as the source of the flavour. The paler the beer the stronger the almond, if it happens to the beer, based on my experience.

Campden tablets get used up really quickly, vitamin c acts much slower but stays longer. My theory is that even some vitamin c caries over into the bottle and protects the beer that way much longer than campden would.
 

TheMadKing

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So I wanted to bring this back, I have another Scottish export with this flavor and I'm 99% sure it's ethyl acetate except I can't understand what I did to my yeast to stress them. I fermented with white labs Scottish ale yeast at 63F, I used direct oxygen in the wort, I used yeast nutrient, and a 2L starter.

But my wife says it tastes chemically up front, and I taste strong almonds with a hint of hot solvent at the end. I've had this show up in almost all of my malty beers lately, and it's especially prominent in beers with simple sugars and crystal malt.

I'm pretty frustrated since this is the third iteration of this beer I've made and it's gotten much worse not better. Has anyone got any ideas?
 

TheMadKing

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I just found a write up from Scott Janish where he found a study that showed adding Servomyces yeast nutrient increased esters

"the addition of ZnS04 and L-leucine [Servomyces] Specifically, 0.12 g/l of ZnS04 resulted in a 27% increase in acetate esters and 123% increase in total ethyl esters compared to unsupplemented sample. The addition of 0.750 g/l of L-leucine resulted in a 41% increase in total acetate ester concentration and 84% increase in total ethyl ester concentration compared to unsupplemented sample.11"


I've been using Servomyces in all my beers for the last couple years and it definitely coincides with noticing this off flavor starting to appear.
 

pvtpublic

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I have a few questions to throw out there that I don't believe have been asked yet (correct me if I'm wrong).

What yeast are you pitching? How old is it? What pitching rate?

What temp are you fermenting at? Is it consistent? How do those Temps compare to when you were in England?

What is your ferment schedudule? Do you use a primary and secondary? Or do do you do straight through primary?

This almond flavor, is it a bit like bubble gum? Fresh or stale almond? Cardboard? Fresh cut green apple?
 

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TheMadKing

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I have a few questions to throw out there that I don't believe have been asked yet (correct me if I'm wrong).

What yeast are you pitching? How old is it? What pitching rate?

What temp are you fermenting at? Is it consistent? How do those Temps compare to when you were in England?

What is your ferment schedudule? Do you use a primary and secondary? Or do do you do straight through primary?

This almond flavor, is it a bit like bubble gum? Fresh or stale almond? Cardboard? Fresh cut green apple?

I believe we've discussed most of those variables.

Different yeast, calculated cell counts and building up starters with stir plates, fresh yeast

Various fermentation temps (my latest batch was 63F). Controlling temps with a glycol chiller and coil in a spike conical.

I do a single stage ferment until terminal gravity is reached and cold crash under pressure and closed transfer to a liquid purged keg.

The almond flavor to me is like someone added almond extract right at the flavor threshold in the beer. There's no hint of oxidation cardboard and there are low levels of acetaldehyde green apple to it but that is standard for English ale yeasts and an acceptable flavor.

Sorry I've been through all the standard off flavors many times. I've been brewing for 15 years and am a beer judge as well. I've thoroughly examined all the basics and am convinced this is a more complex issue.

From the article I posted above I'm really leaning toward Servomyces being the problem, but I'd like @Miraculix to confirm whether he's using that (or a similar yeast nutrient).
 
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TheMadKing

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I know you don’t like information from books written by old dead Germans however Kunze gives us some interesting clues here:

3.4.1.6 Thermal exposure of the wort
During boiling, further Maillard products and Strecker aldehydes are formed, tannins oxidized and thus the the thermal exposure of the wort is further increased.

And here we find in this paper..
Impact of Wort Amino Acids on Beer Flavour:
Inês M. Ferreira and Luís F. Guido

these descriptions of the compounds in question.

Strecker Degradation Products
2-methylpropanal - Grainy, varnish, fruity
2-methylbutanal - Almond, apple-like, malty
3-methylbutanal - Malty, chocolate, cherry, almond
Methional - Cooked potatoes, worty
Phenylacetaldehyde - Hyacinth, flowery, roses
Benzaldehyde - Almond, cherry, stone

It certainly looks like the smoking gun.

What percent of the initial volume do you lose during the boil?
Hey Bilsch

Do you know whether there are other pathways for these aldehyde productions by yeast? Or maybe @Northern_Brewer or @VikeMan has any insight?

I'm pretty skeptical that it's oxidation or heat stress on my wort and here's why:

I presently have a Scottish export and a marzen, both brewed using the same system, both brewed using the same mash and lauter processes, same yeast handling techniques, same amount of wort oxygenation, same yeast nutrient. I use an electric spike system and boil at 3850 watts every time. (the heating element will run at 100% or 5500 watts until it registers boiling on the PID, so there may be some heat stressing during initial heating to boil.) my boil-off rate is 1.2 gallons per hour.

The marzen has no hint of this almond-like (almond extract, artificial cherry, very slight alcohol warmth) flavor, while the Scottish export is a bomb straight from the fermenter!

The biggest differences between the two recipes are that the marzen obviously used a lager yeast and the Scottish ale used white labs Scottish ale yeast, and the Scottish ale also contained a high percentage of simple sugars (invert and dark brown sugar). I fermented both right at the low end of the respective yeasts' temperature ranges as well, so they should not be throwing excessive esters.

I notice that this flavor seems to occur in beers using English ale yeasts which tend to favor ester production. I've had it most prominently in an irish red, 2 scottish exports, and an english brown ale, and a english strong bitter.

I feel that I'm very strong on cold side oxygen reduction and use a closed process from yeast pitch to a liquid purged keg.

So I suspect that what I'm tasting is one of these aldehydes but I think it has been synthesized from some chemical change to a yeast ester. OR I'm tasting a combination of yeast esters and my brain is simply mistaking the combination for almond-extract (I'm certainly not ruling out that this is simply a sensory/descriptor issue)

Does any of that sound plausible to you?
 
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Miraculix

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I for myself found the main source, but this obviously doesn't have to be the reason for your problem as well.

The hot side stuff with the vitamin c helped, but the almonds showed still up now and then. Not as strong as before, but still sometimes there.

I found out that my fermenter developed a small leak. After fermentation finished, my air lock would not keep floating but slooooowly start to sink in the water. Indicating that gas can leave the space below it and so it could also enter. If I recognized that quickly and screwed the lid back on tightly, almond results were very small. If I ignored it the almonds popped up again much stronger.

I fixed that, plus all the hot side stuff and the combination resulted in zero almonds.

So fast chill, no hot side transfers that introduce an abundance of 02, optional vitamin c plus an air tight fermenter did it for me.

Not that much magic... I'm pretty sure that I'm a bit overly sensitive to these almond flavours though, which doesn't help.

I forgot, I never use nutrients in my beers.

And another thing, I also had the feeling that the almond gets emphasized by English yeasts somehow.
 
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TheMadKing

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I forgot, I never use nutrients in my beers.

And another thing, I also had the feeling that the almond gets emphasized by English yeasts somehow.

Well that's disappointing, that yeast nutrients aren't a silver bullet here. I'm pretty convinced that I'm getting extra ester expression from my yeast somehow, since all else being fairly equal, I don't taste this flavor unless I use an expressive yeast. Maybe I need to play around with pitch rates and see if I can affect it that way - I'd rather change one thing in my process to fix it, rather than overhaul my entire yeast handling procedures.

Thanks!
 
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Miraculix

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Well that's disappointing, that yeast nutrients aren't a silver bullet here. I'm pretty convinced that I'm someone getting extra ester expression from my yeast somehow, since all else being fairly equal, I don't taste this flavor unless I use an expressive yeast. Maybe I need to play around with pitch rates and see if I can affect it that way - I'd rather change one thing in my process to fix it, rather than overhaul my entire yeast handling procedures.

Thanks!
Drop the nutrients just for one batch and see where this leads you. It's certainly possible to brew great beer without any.
 

TheMadKing

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Drop the nutrients just for one batch and see where this leads you. It's certainly possible to brew great beer without any.
Oh I certainly plan to after reading Scott's article. Maybe I'm being too nice to my yeast and they are getting all excited and spraying esters everywhere!
 
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Miraculix

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Oh I certainly plan to after reading Scott's article. Maybe I'm being too nice to my yeast and they are getting all excited and spraying esters everywhere!
Please let me know! I'm actually also giving them an abundance of nutrients, as I'm throwing in most of the trub after the boil.... So this might put me in a similar spot.

For head retention reasons, I'm going to try to limit the trub within the next batch though.
 

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Please let me know! I'm actually also giving them an abundance of nutrients, as I'm throwing in most of the trub after the boil.... So this might put me in a similar spot.

For head retention reasons, I'm going to try to limit the trub within the next batch though.
Scott mentioned that in his write up as well and indeed he found a study showing a correlation between hi trub and higher ester levels

I wonder if we have an amino acid problem on our hands
 
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Miraculix

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Scott mentioned that in his write up as well and indeed he found a study showing a correlation between hi trub and higher ester levels

I wonder if we have an amino acid problem on our hands
I was thinking the same thing.... I think I even read what Scott wrote that you are referring to.
 

pvtpublic

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I believe we've discussed most of those variables.

Different yeast, calculated cell counts and building up starters with stir plates, fresh yeast

Various fermentation temps (my latest batch was 63F). Controlling temps with a glycol chiller and coil in a spike conical.

I do a single stage ferment until terminal gravity is reached and cold crash under pressure and closed transfer to a liquid purged keg.

The almond flavor to me is like someone added almond extract right at the flavor threshold in the beer. There's no hint of oxidation cardboard and there are low levels of acetaldehyde green apple to it but that is standard for English ale yeasts and an acceptable flavor.

Sorry I've been through all the standard off flavors many times. I've been brewing for 15 years and am a beer judge as well. I've thoroughly examined all the basics and am convinced this is a more complex issue.
Sorry, I had just came from a BJCP study group and we did weizenbock, doppelbock, and eisbock, so I definitely wasn't tracking as well as I thought was haha.
 
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