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

[Erik the Anglophile]

I usually get a bit of air in the tubing when I drain of from the lautering bucket to the BK. But I think none but the most hardcore LODO-ists would argue that it would have that much of an impact. Have you tried boiling longer?

 

[Miraculix]

Have you made any raw beer recently? Wonder if you could detect it in a no boil.

I was thinking about it as well! My last raw beer was years ago, but I cannot remember tasting anything almond-ish there. Maybe I will brew an english raw bitter next, just to see.

I usually get a bit of air in the tubing when I drain of from the lautering bucket to the BK. But I think none but the most hardcore LODO-ists would argue that it would have that much of an impact. Have you tried boiling longer?

I think I did try boiling longer back in the Uk, but I do not know for sure.

I’m pleased we can have this conversation about any and all brewing techniques.

That being said, Ive never experienced the off flavor you have described in all my hido days and certainly not after. Additionally amongst the other group no one has mentioned it either. Oxidized precursors are required for the Strecker degradation but usually also heat to complete. Is it possible that your mash is introducing heat stress through the mechanical heating or just running too long at too high of temperatures?

If you want to try and limit the oxygen in your mash we can certainly help you with the easiest and best ways to accomplish that.

I thought so as well, that´s one of the reasons I ditched the biab system with which I was heating the whole thing in a pot on the stove while stirring, to reach the different temperature steps. I though uneven heat distribution, maillard reactions, oxidation.... But it did not solve the issue as I am facing the same off flavour now with a Full volume single infusion mash with normal Vorlauf/lauter system. So no way for heat induced stress, just 65 C mash in and from there, no more heat till the boil kettle (did this intentionally with my last batch, I usually at least mash out).

I also do not think that it actually is the mash. I once or twice deoxigenated my water with the baking yeast plus a bit of sugar and one day waiting trick, did not do anything detactably good or bad.

I am really wondering if this Vorlauf/Lauter silicon hose is the culprit. The hose is never even partially full with wort when running the wort through it, so there is about 1.0 m long silicon hose through which the wort runs and mixs with the air all the time due to internal turbulences.

But on the other hand, why did I also have this issue with biab back then? Not as often as now, but still, it was there.

 

[Bilsch]

I am really wondering if this Vorlauf/Lauter silicon hose is the culprit. The hose is never even partially full with wort when running the wort through it, so there is about 1.0 m long silicon hose through which the wort runs and mixs with the air all the time due to internal turbulences.

This setup does sound like a good way to oxidize the wort at least to a certain degree. And of course you already know the hotter wort, the faster these reactions proceed. If you give it heat, surface area and an exchange of air it will be happening. Silicone is also particularly highly permeable to oxygen so that is not helping the situation either.

It is curious you get this since are plenty of mashes being very well aerated by brewers on this forum each and every day followed by intense boils. So you'd think someone else would have run into this marzipan flavor by now.

Two more points to ponder.. everyone is unique in their sensitivity to different compounds. Is it possible that you are just particularly attune to this one? I have also noticed as the years have gone by and my brewing skills improve, I'm able to reduce or eliminate some flaws in my beers which allows others jump forward that were always there but hidden under poor attenuation, yeast esters, herbstoff, husk astringency et. al. Is it possible that you have upped your game and thus uncovered things you never knew were always there?

 

[Bilsch]

I also do not think that it actually is the mash. I once or twice deoxigenated my water with the baking yeast plus a bit of sugar and one day waiting trick, did not do anything detactably good or bad.

I just wanted to address this for a moment.
Removing the oxygen from the strike water is a good first step toward reducing HSA but really is only a small drop in the bucket if further protections aren't also put in place. Your water, depending on the temperature, probably contains about 4-5ppm dissolved oxygen. Then you add the grain with stirring and you have quickly added that amount back plus some, so simply de-aerating the strike water ends up doing nothing. There are two ways for us at the homebrew scale to provide the further protection, the first being inert gas purging the grain and the second to add active oxygen scavengers to the strike water. Commercial breweries don't need to do either because they have expensive wet mills and or vormaischers that get around these problems we are stuck with. Also scale of their kettles is a big advantage.

Note: If anyone is interested in the technology mentioned above, see this patent for one example: DE202013100550U1 - Shot and mash device - Google Patents

P.S. I always wonder about that yeast method for de-aeration.. I hear the guy that came up with that is kinda shifty.

 

[Miraculix]

This setup does sound like a good way to oxidize the wort at least to a certain degree. And of course you already know the hotter wort, the faster these reactions proceed. If you give it heat, surface area and an exchange of air it will be happening. Silicone is also particularly highly permeable to oxygen so that is not helping the situation either.

It is curious you get this since are plenty of mashes being very well aerated by brewers on this forum each and every day followed by intense boils. So you'd think someone else would have run into this marzipan flavor by now.

Two more points to ponder.. everyone is unique in their sensitivity to different compounds. Is it possible that you are just particularly attune to this one? I have also noticed as the years have gone by and my brewing skills improve, I'm able to reduce or eliminate some flaws in my beers which allows others jump forward that were always there but hidden under poor attenuation, yeast esters, herbstoff, husk astringency et. al. Is it possible that you have upped your game and thus uncovered things you never knew were always there?

Exactly my thoughts, especially why I seem to be the only one and the following reasoning. It might be that my taste evolved, it might also be that I am overly sensitive for this particular off flavour. I know of other guys who are, for example, overly sensitive for diacethyl, they taste it even in most commercial beers. I cannot rule that one out unless I get somehow a sample which has this off flavour causing substance, but underneath the normal taste threshhold. If I would taste it, riddle solved.

What I don´t think is that my process evolved so significantly, that this one off-flavour is now uncovered. My process did evolve a bit, but not that much. I managed to brew the perfect beer once with this process (really, it was just perfect, everybody who had it agreed, the perfect english bitter, I never managed to brew it again, recipe is Miraculix Best in the ale forum) and I managed to brew Seargent Nutty, The King Of The Almonds with it as well

Now I changed parts of the system but same storry (except for the perfect beer, unfortunately).

I just wanted to address this for a moment.
Removing the oxygen from the strike water is a good first step toward reducing HSA but really is only a small drop in the bucket if further protections aren't also put in place. Your water, depending on the temperature, probably contains about 4-5ppm dissolved oxygen. Then you add the grain with stirring and you have quickly added that amount back plus some, so simply de-aerating the strike water ends up doing nothing. There are two ways for us at the homebrew scale to provide the further protection, the first being inert gas purging the grain and the second to add active oxygen scavengers to the strike water. Commercial breweries don't need to do either because they have expensive wet mills and or vormaischers that get around these problems we are stuck with. Also scale of their kettles is a big advantage.

Note: If anyone is interested in the technology mentioned above, see this patent for one example: DE202013100550U1 - Shot and mash device - Google Patents

P.S. I always wonder about that yeast method for de-aeration.. I hear the guy that came up with that is kinda shifty.

That is basically a mix of assumptions here. I certainly introduce oxygen during the mash in (I have the grain in the mash bucket and fill it up with hot water, so not as bad as stirring the grain in, more like a wrathfull underletting. Afterwards it gets stirred). But how much oxygen is introduced is a bit of a guess and how much it matters at this temperature is also a bit of a guess. Oxygen dissolves differently in heated water, but do not ask me how it actually affects the oxygen/time being dissolved. Usually gasses dissolve better in cooler liquids and if I think how long the small headpsace of a filled bottle needs to get its oxygen into the liquid (weeks), I am tempted to say that the little oxygen I introduce during mashing, cannot be the reason for this off flavour. But this is obviously an assumption as well.

 

[Yooper]

A little web sleuthing comes back with benzaldehyde as a likely culprit. If this is really driving you crazy, maybe purchase some food-grade benzaldehyde to see if that's it?

That's the first thing that jump at at me. Oxidation of malt compounds causes an "almond" or marzipan flavor. It's likely post-fermentation oxidation.

 

[Miraculix]

That's the first thing that jump at at me. Oxidation of malt compounds causes an "almond" or marzipan flavor. It's likely post-fermentation oxidation.

Post fermentation is unlikely, as it is the strongest directly after fermentation finished. The hydrometer sample when bottling is always the strongest example of this off flavour. If it is not extremely strong (differs from beer to beer), sometimes it even fades with time, sometimes it fully disappears. Sometimes it just gets less pronounced with time. My marzipan AK for example, still tastes like marzipan, even after half a year in the bottle... but not as strong as it was before the aging.

 

[Miraculix]

OK I had another idea. How about that:

The question for me is, why I sometimes had it in the UK, not everytime though, and now have it with a different system in Germany as well.

I might found out why. In the UK I used to do no chill biab. I also used to throw the hot wort directly out of the kettle into the fermenter, to heat sanitise the fermenter. I airlocked it and let it cool over night. I obviously introduced lots of oxygen during the "transfer" (literally just dumping it from kettle into fermenter) and after that it stayed hot for long time. Meaning oxygen and elevated temperatures were both present for hours. Also, more proteins in the wort because I used to dump all in, trub and all.

It might be that I did not introduce as much oxygen with biab as I am doing now with the faulty vorlauf/lauter, but dumping the liquid and then no chill seem to tick the boxes for possible oxidation as it had that much more time to oxidise.

With the faulty vorlauf/lauter and chill system, I introduce the oxygen pre boil and probably much more then with the biab system. So the shorter time the wort is heated might be enough here because of the extra dose of oxygen.

In the meantime, I got myself a wort chiller. So next beer will be biab again, but with a chilled wort, no excessive splashing and single infusion. I will use the yeast method to rid the water of O2, just because I can.

If this works, we narrowed it down to the lauter/vorlauf aeration.

 

[Beer666]

I seem to be dong a similar method to you. The only difference would be i use a cube and fill it to the top. What a pita, i hope you manage to resolve it.

 

[Miraculix]

I seem to be dong a similar method to you. The only difference would be i use a cube and fill it to the top. What a pita, i hope you manage to resolve it.

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

 

[Beer666]

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.

 

[Miraculix]

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.

 

[Erik the Anglophile]

Hmm. I drain via a silicone hose in to my BK when I sparge, usually get a little turbulence in the hose. But I have never picked up any almond flavor.

 

[Miraculix]

Hmm. I drain via a silicone hose in to my BK when I sparge, usually get a little turbulence in the hose. But I have never picked up any almond flavor.

How long is the distance in the hose from vessel to vessel? Mine is approximately 1m.

 

[Erik the Anglophile]

I'd guess about the same maybe a little less.

 

[Erik the Anglophile]

I'll have to be on the lookout for marzipany beer...

 

[Miraculix]

I'll have to be on the lookout for marzipany beer...

Marzipan..... When you are expecting it the least...... It ... It......




It is going to hit your beer!!!!

 

[IslandLizard]

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.

 

[Miraculix]

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]

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]

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]

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]

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]

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.

 

[Miraculix]

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.

 

[Witherby]

If you can’t beat ‘em, join ‘em.

Special Ingredient: Marzipan

 

[kent_a]

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.

 

[Miraculix]

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%

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:
https://www.homebrewtalk.com/threads/vitamin-c-the-game-changer.698328/

 

[kent_a]

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!

 

[Miraculix]

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.