That "cheerios" character after bottling

[loctones]

I made my first attempt at blending sour beers a few months ago. Of the three beers that went into the blend, only one had some of the cheerios character. Admittedly, it did make up 40% of the blend. After about 6 weeks in the bottle, I tried one, and the cheerios character was VERY prominent. Much more so than when I bottled it.

I've not had this cheerios character in my sour beers before. This is the first set of sour beers I've brewed with half or more of the grist being raw or malted wheat, for what it's worth. I love the raw bready character I'm getting in these beers, but not the cheerios component.

In your experience, how long does it take for the cheerios character to go away? I only have 11 bottles of the first batch, so I don't want to drink too many while it's still there.

 

[davejanssen]

Sorry I can't offer experience on when the cheerios character goes away, but i believe that flavor is what people are talking about when they say 'mouse taint' if that helps at all in searching for answers.

 

[kingwood-kid]

Themadfermentationist says a few months and that it's a product of the bottling process. I think the book is a little more detailed but alas, I'm too lazy to go get it. I know Brett acts differently under pressure, although this could be Pedio or something else. Brett does have a history of cleaning up after Pedio. I've never noticed this in my limited sours that are more bretty than Pedio, but maybe I don't taste well or just got lucky. Anyway, try another next year sometime.

 

[Oldsock]

The two leading candidates are diacetyl and tetrahydropyridines (toasty at low levels, "mouse taint" aka urine at higher). I’m inclined towards the latter, but I know where diacetyl goes (converted to 2,3-Butanediol), while I’m unsure what path if any is available for the destruction of tetrahydropyridines. In the end it doesn’t really matter what the compound is, just that it dissipates after 2-4 months in bottles stored at cellar temps.

Good luck!

 

[loctones]

Thanks, all. I've read about "mouse taint" and that never really made any sense to me. Urine is more understandable. I'm happy to hear that it dissipates after 2-4 months. My beer is almost 4 months in the bottle, now. Time to throw one in the cooler and give it a try!

 

[loctones]

I'm drinking a glass of it right now. The beer has been in the bottle just under 4 months. The cheerios thing has gone way down. It's still there a bit. It's more pleasant at a lower level. Toasty was a good descriptor. If it drops just a touch more it'll be a nice component of the beer instead of an annoyance.

The funk has also increased quite a bit in the bottle. I've read of that happening, but not experienced it on the previous batches I've bottled.

Overall, it's improved a ton in the last 2 months. In general, I guess it's probably a good idea to expect my sour beers to take 3-6 months in the bottle to come together. Good thing I have a nice pipeline going!

 

[ne0t0ky0]

In 4 or 5 of my sours, its never faded away to the point of not being noticeable, even after a year. I wish I knew how to prevent it from occurring in the first place. I've tasted it at that very minimal level in some recently bottled commercial sours which did go away in a month more of conditioning, but I've not had that luck in my homebrew. The best advice I've had was reduce O2 exposure and use 60F as a cellaring temp target.

 

[Wahoo]

I had much more of that character when I was using large amounts of a culture that contained mostly bottle dregs. The commercially available blends have tended, for me, to produce less of this character.

If it is diacetyl, then making sure you have enough brett in your culture would be another good place to start.

 

[Oldsock]

In 4 or 5 of my sours, its never faded away to the point of not being noticeable, even after a year. I wish I knew how to prevent it from occurring in the first place. I've tasted it at that very minimal level in some recently bottled commercial sours which did go away in a month more of conditioning, but I've not had that luck in my homebrew. The best advice I've had was reduce O2 exposure and use 60F as a cellaring temp target.

I find that pitching rehydrated wine yeast at bottling reduces the amount/duration of the flavor. Having something besides the Brett consume the priming sugar.

 

[ne0t0ky0]

In 4 or 5 of my sours, its never faded away to the point of not being noticeable, even after a year. I wish I knew how to prevent it from occurring in the first place. I've tasted it at that very minimal level in some recently bottled commercial sours which did go away in a month more of conditioning, but I've not had that luck in my homebrew. The best advice I've had was reduce O2 exposure and use 60F as a cellaring temp target.

I have to update this. My first long bottle aged beer, bottled on 12/30/13 has recently turned around and dropped out the cheerios background that used to be present even just 4 weeks ago.

This really gives me hope for my other beers which have had a bit too much of that flavor for my liking.

That said I'm now bottling with Champagne yeast as suggested by Oldsock.

 

[dougdecinces]

I find that pitching rehydrated wine yeast at bottling reduces the amount/duration of the flavor. Having something besides the Brett consume the priming sugar.

Odd, in October my friends and I bottled a batch of a Belgian Strong Ale aged in an infected apple brandy barrel. All of us used champagne yeast to carb our batch except for one person who used the CBC yeast. Three months later and all of ours have the "mouse taint" flavor except for him.

 

[ne0t0ky0]

Both Lacto and Pedio can also produce the "mousy flavor", ATHP/ETHP;

I've also had a similar flavor profile change: fermentation finishes cleanly after 30 days, at about 45 to 60 days, the mouse flavor kicks up quite a bit, only to fade later.

Other than *long* conditioning in the bottle (a year for me), prevention of the flavor in the first place is the only defense I know of. That's lower temps (60s F) and reduced oxygen (recommendations from professional sour beer brewery).

In my limited research/reading about ATHP, it will happen, much like diacetyl is a by-product of the yeast cycle, the precursors are L-lysine and ethanol, combine with *sugar* aka, priming, and it's more than likely to happen.

Research suggests that *oxygen* is a component, but I've not read anything conclusive at the moment.

I believe the recommendation of wine yeast will help by ensuring that an active yeast consumes the sugar before the lacto/pedio can start utilizing it to produce ATHP.

 

[dantheman13]

Thanks for info on this, everyone. Subbed for follow ups!

 

[dantheman13]

I wrote up an article over on the MTF Wiki to try and get some of this information in one spot: http://www.milkthefunk.com/wiki/Tetrahydropyridine

 

[loctones]

Thanks for pulling this information together, dantheman13. I noticed the following on your wiki page:

2-ethyltetrahydropyridine (ETHP/ETPY)
Taste threshold (wine): 150 µg/L
Concentration reported in wines exhibiting mousy off-flavour: 2.7-18.7 µg/L

I'm not sure it matters, since I have no idea how I'd measure the actual amounts, but it looks like the reported level is way below the taste threshold.

My first batch with the cheerios component is about 7 months in the bottle, now, and tasting nice. The cheerios component is still there at a very low level, but I actually think it adds to the beer. I like a little bit of it in the finish.

On another note, I bottled my second shot at blending a pale sour last weekend. I typically add 71B yeast to my long-aged beers. Oldsock's comment about how adding yeast at packaging was interesting to me. As a test, I bottled the first 6 bottles without any additional yeast. I'll compare them at 6 months and we'll see what happens.

 

[dantheman13]

Thanks for pulling this information together, dantheman13. I noticed the following on your wiki page:

I'm not sure it matters, since I have no idea how I'd measure the actual amounts, but it looks like the reported level is way below the taste threshold.

My first batch with the cheerios component is about 7 months in the bottle, now, and tasting nice. The cheerios component is still there at a very low level, but I actually think it adds to the beer. I like a little bit of it in the finish.

On another note, I bottled my second shot at blending a pale sour last weekend. I typically add 71B yeast to my long-aged beers. Oldsock's comment about how adding yeast at packaging was interesting to me. As a test, I bottled the first 6 bottles without any additional yeast. I'll compare them at 6 months and we'll see what happens.

Yeah that threshold was cited from a wine study, and might not reflect beer thresholds. I'll put a note about that in the article. Also, you make a good point about this flavor not necessarily being a bad thing in small amounts.

 

[Wahoo]

I'm confused about one thing. How did we get from cheerios character to mousy? I think of mousy as being very different-- basically, mammal urine. Nothing like the cheerios compound which is sweet and grainy.

 

[ne0t0ky0]

I'm confused about one thing. How did we get from cheerios character to mousy? I think of mousy as being very different-- basically, mammal urine. Nothing like the cheerios compound which is sweet and grainy.

A couple of things, I think this one[1] , slide 10

"Tetrahydropyridines (Mouse urine [High] , Bready [Low])"

Additionally, I personally made the connection through sensory feedback as I tasted some of my first sours, noting the grainy flavors on the finish, but not in the aroma.

My association with ATHP and mousy was uncovered in one of the wine papers which mentioned that the volatility of the flavor happens only in the mouth; that is, you cannot "smell" ATHP, it's something you get in the aftertaste because the pH of your mouth modifies the makeup and releases the compounds that we detect.

"The production of a mousy odor by Brettanomyces is a rare phenomenon compared with mousy taint caused by lactic acid bacteria. The mousy off flavor from Brettanomyces contamination is caused by the compounds 2-acetyl- tetrahydropyridines (ATHP) and 2-ethyltetrahydropyridine (ETHP). ATHP is produced from L-lysine and is converted, over time, to ETHP. Both of these compounds produce the mousy character in wine. This character is often difficult to detect until the wine is taken into the mouth. This can be a most unpleasant surprise." [2]

Found another one[3], though this once blends aromas with ATHP versus other Brett aromas (horsey is a different phenol):

"The tetrahydropyridines are responsible for the mousy aroma often associated with Brettanomyces infection.
The aroma of tetrahydropyridines is largely affected by its concentration in the wine; at low concentrations it may
have a bready, popcorn or cracker aroma, but at higher concentrations it may have the more obnoxious mousy
or horsy aroma. The occurrence of mousy aroma does not necessarily indicate that a Brettanomyces infection
is responsible. Tetrahydropyridines arise not only from Brettanomyces, but may also be synthesized by
heterofermentative lactobacilli such as Lactobacillus brevis and L. hilgardii. The substrates required for
heterofermentative lactobacilli such as Lactobacillus brevis and L. hilgardii. The substrates required for
synthesis of these very volatile compounds are lysine, and either ethanol or propenol."


1. http://www.ahaconference.org/wp-content/uploads/presentations/2008/GregDoss_BrettBrewing.pdf
2. http://wineserver.ucdavis.edu/indus...ey/postfermentation_classes_of_compounds.html
3. http://www.burgundy-report.com/wp/wp-content/uploads/2009/10/Understanding-Brettanomyces.pdf

 

[Wahoo]

Mousy is different than horsey? Isn't a mouse just a tiny horse?

Seriously though, thanks for the thoughtful response. Interesting that the 3rd citation above mentions the popcorn character. I definitely get *that* character at elevated concentrations (although maybe not "high") which is one of the reasons I have subscribed to the hypothesis that it's diacetyl I'm tasting.

Also very interesting is the 2nd citation-- describing how ATHP can't be detected by aroma and must be tasted. This absolutely has been my experience with the cheerios character I sometimes get in my sours. Although on the other hand, I have heard diacetyl described as an aroma but I've always been only able to detect it in my mouth (flavor/mouthfeel).

Perhaps one more small data point from my personal experience. I recently was feeding a brett brux culture I have going and tasted the spent wort and it was loaded with this character. If it is, in fact diacetyl, I wouldn't expect it to show up in a brett-only culture. Although this culture is being stored at 55F basement temps, certainly not ideal. It's also possible that I have a LAB infection in this culture.

 

[dantheman13]

Mousy is different than horsey? Isn't a mouse just a tiny horse?

Seriously though, thanks for the thoughtful response. Interesting that the 3rd citation above mentions the popcorn character. I definitely get *that* character at elevated concentrations (although maybe not "high") which is one of the reasons I have subscribed to the hypothesis that it's diacetyl I'm tasting.

Also very interesting is the 2nd citation-- describing how ATHP can't be detected by aroma and must be tasted. This absolutely has been my experience with the cheerios character I sometimes get in my sours. Although on the other hand, I have heard diacetyl described as an aroma but I've always been only able to detect it in my mouth (flavor/mouthfeel).

Perhaps one more small data point from my personal experience. I recently was feeding a brett brux culture I have going and tasted the spent wort and it was loaded with this character. If it is, in fact diacetyl, I wouldn't expect it to show up in a brett-only culture. Although this culture is being stored at 55F basement temps, certainly not ideal. It's also possible that I have a LAB infection in this culture.

Diacetyl seems completely different to me (butterscotch). Do you mean DMS (corn flavors)?

 

[Wahoo]

Nope, not DMS. Diacetyl. Not so much butterscotch in such a dry beer, but butter. Buttered popcorn, in fact.

 

[dantheman13]

Nope, not DMS. Diacetyl. Not so much butterscotch in such a dry beer, but butter. Buttered popcorn, in fact.

Personally, I can't make that leap in comparing these flavors. Diacetyl and ATHP do appear on the palate in the same spot when I swallow, but the two flavors are vastly different to me.

 

[comoxlandia]

Came across this thread via the MTF page on THP and wanted to add my small data point as it pertains to champagne yeast and THP in sour beers. I recently bottled a mixed ferm sour and wasn't until halfway thru bottling that I realized I'd forgotten to add my champagne yeast (EC-1118). I added an appropriately reduced amount of rehydrated champagne yeast and bottled the 2nd half of the batch. All bottles were stored at room temp with half with champagne yeast, half without. Both wewe thru a THP phase but lo and behold the btls with EC-1118 cleared the THP at least 3-4 weeks earlier. Thankfully no other discernible differences in the beer in terms of flavour and the non-yeast btls did also eventually clear the THP as well.

I now bottle all my mixed fermentation beers with champagne yeast.

 

[couchsending]

Came across this thread via the MTF page on THP and wanted to add my small data point as it pertains to champagne yeast and THP in sour beers. I recently bottled a mixed ferm sour and wasn't until halfway thru bottling that I realized I'd forgotten to add my champagne yeast (EC-1118). I added an appropriately reduced amount of rehydrated champagne yeast and bottled the 2nd half of the batch. All bottles were stored at room temp with half with champagne yeast, half without. Both wewe thru a THP phase but lo and behold the btls with EC-1118 cleared the THP at least 3-4 weeks earlier. Thankfully no other discernible differences in the beer in terms of flavour and the non-yeast btls did also eventually clear the THP as well.

I now bottle all my mixed fermentation beers with champagne yeast.

Have you tried other dry yeasts? Or just champagne yeast?