Fusel alchohol production

[vicratlhead51]

I was talking to one of the guys at work and he was asking if my homebrews give me a headache or a bad hangover and I said no I think if a homebrew does do this its from high fermentation temps causing the yeast to produce fusel alchohols. As long as the temps stay in the yeast's proper range it shouldn't cause this. His response was "oh really? I went to a brewery in wisconsin and it was hot as hell in there. Why don't they have that problem?" I didn't really have a response. My guess is he was confused and was there during a boil and not fermentation. It did get me thinking though, how do big brewerys keep fermentation temps down? I mean you could keep the outside cool but what about the middle? Do they have a chilling system for fermentation? Can homebrew actually cause less of a hangover since our small batches are really easy to control? I'm assuming since he asked me this that he must have had some one elses homebrew that something went wrong with. What else in beer can cause nasty hangovers? Sorry for all the questions but I kind of like to have an answer when somebody asks.

 

[MalFet]

Fusal alcohols are definitely the primary culprit. A lot of breweries use glycol chillers, water jackets, or keep their fermentors in temp controlled cellars. There's also a difference to consider relating to fermentation volume. Many commercial breweries ferment 5-10 degrees hotter than homebrewers would, but there are a couple reasons they can get away with this. They're often pitching a lot more yeast than we are, and the hydrostatic pressure of a 500 barrel fermentor makes the yeast behave differently than it does in a 5 gallon fermentor. Still, temperature control is as important to them as to us, if not more so.

 

[DrawTap88]

Also, yeast provide vitamin B (I think that's the vitamin) when drinking homebrew. Drinking any sort of alcoholic beverage depleats that vitamin, which is one of many causes of hangovers.

Today I Found Out - What Causes Hangovers

 

[kanzimonson]

Definitely inform your coworker that breweries work hard to control their fermentation temps. I went to a brewery once where they described an incident when somebody forgot to hook up the glycol, or set it correctly, and basically the yeast got the batch up into the 100s for temp before anyone noticed.

 

[cactusgarrett]

I've made a couple beers initially exhibiting that hot alcohol flavor, and my temps were actually on the low end of the yeast's "preferred" range. In those cases, though, the beers were pretty big. Sometimes a beer is just bigger (gravity) than the yeast can handle and it takes a little longer for conditioning to clean that up.

 

[kanzimonson]

I've made a couple beers initially exhibiting that hot alcohol flavor, and my temps were actually on the low end of the yeast's "preferred" range. In those cases, though, the beers were pretty big. Sometimes a beer is just bigger (gravity) than the yeast can handle and it takes a little longer for conditioning to clean that up.

I'm not 100% sure what I'm talking about here so take it with a grain of salt, but I've heard that actual fusel alcohols will, at best, only barely be reduced through oxidation and esterification. So it seems more likely that if any harsh flavors were reduced, it's probably not alcohol but some other yeast byproduct.

 

[vicratlhead51]

Cool, the responses were just what I was looking for. Thanks for that link Drawtap88 and all the other replies. Satisfied my curiosity, also explained why I rarely get hungover since I'm a slow drinker and like to savor my beers....most of the time.

 

[smokewater]

I've made a couple beers initially exhibiting that hot alcohol flavor, and my temps were actually on the low end of the yeast's "preferred" range. In those cases, though, the beers were pretty big. Sometimes a beer is just bigger (gravity) than the yeast can handle and it takes a little longer for conditioning to clean that up.

New Brewer here. Is fusel alcohol production something leaving a beer on primary longer would clean up? Thanks

 

[MalFet]

New Brewer here. Is fusel alcohol production something leaving a beer on primary longer would clean up? Thanks

Conditioning in primary will clean up a lot if flaws, but won't decompose fusels. If you get fusel alcohols in your beer, you are pretty much stuck with them.

 

[smokewater]

Conditioning in primary will clean up a lot if flaws, but won't decompose fusels. If you get fusel alcohols in your beer, you are pretty much stuck with them.

Thanks!

 

[Wyrmwood]

Conditioning in primary will clean up a lot if flaws, but won't decompose fusels. If you get fusel alcohols in your beer, you are pretty much stuck with them.

Unless you filter

 

[MalFet]

Unless you filter

I would love to be proven wrong on this, but I am mighty skeptical that filtering can remove heavy alcohols. Got a source?

 

[Calder]

Fusel alcohols are also produced when under-pitching. Often times there is a trade-off between under-pitching slightly to get more flavors, and too much which makes it hot. I would say under-pitching is largely overlooked as being the culprit.

High temps also produce them.

The big breweries know what they are doing, pitch known quantities of yeast, and have fermentation controlled to the degree. Higher temps make the process quicker (faster turnaround = more $s), so they push it as high as they can get away with.

Some start low, so they don't overshoot, and let the yeast take the temperature up (maybe 10 degrees), and then maintain it there.

Different strains act differently at different temperatures too. Dupont ferments at 90 F without any issues.

Some fusel alcohols do convert to esters with time. This is how some beers can 'smooth' out over time, a lot of Belgian yeasts tend to do this. Not all do, and I don't know how you know which fusels you have.

 

[Stimulus]

I'm curious about this too, because I have a Wheat brewed with 3068 (Weihenstephan Weizen) and it's heavy in the fusels just enough to be annoying but not ruin it. And I'm baffled by it, because I brew this same beer every few months and this is the first time I've had it produce a lot of fusels.

The variable here was the fermentation temp got really low for a few days early on. This being the only variable I look to it in trying to figure out how this happened, but it goes against what I read about fusel production.

My only theory is the low temp caused enough of the yeast to get pissed and go to sleep creating an underpitching type scenario.

Sound legit or should I look at something else?

 

[MalFet]

I'm curious about this too, because I have a Wheat brewed with 3068 (Weihenstephan Weizen) and it's heavy in the fusels just enough to be annoying but not ruin it. And I'm baffled by it, because I brew this same beer every few months and this is the first time I've had it produce a lot of fusels.

The variable here was the fermentation temp got really low for a few days early on. This being the only variable I look to it in trying to figure out how this happened, but it goes against what I read about fusel production.

My only theory is the low temp caused enough of the yeast to get pissed and go to sleep creating an underpitching type scenario.

Sound legit or should I look at something else?

Hot temps are a common cause of fusels, but really any stress can cause their production (as the previous poster mentioned). This would include a sudden temp drop.

 

[vicratlhead51]

Ooh I didn't know that this was another danger of underpitching, nice to know. I have had some low fermentation temps this winter since I do most of my fermentations in the basement. Some have been a little slow, not to start but to finish. I'll have to think about bringing them upstairs somewhere if I notice that "hot" flavor developing.

 

[MalFet]

Ooh I didn't know that this was another danger of underpitching, nice to know. I have had some low fermentation temps this winter since I do most of my fermentations in the basement. Some have been a little slow, not to start but to finish. I'll have to think about bringing them upstairs somewhere if I notice that "hot" flavor developing.

FWIW, I haven't typically noticed yeast stress from low fermentation temperatures, but from sudden temperature drops. I ferment most of my beers at the very low end of the yeast's range and I get relatively long fermentations, but I think I get a cleaner final product for it. An even temperature is, in many respects, more important than a specific temperature.

 

[Wyrmwood]

I would love to be proven wrong on this, but I am mighty skeptical that filtering can remove heavy alcohols. Got a source?

Scholarly
Commercial
I bought one (at the recommendation of the recipe on the yeast package). I'll do a very unscientific before and after taste test and post the results. If anyone knows some inexpensive way of measuring fusel oils or undesirable fermentation byproducts, I'd be happy to measure the results.

 

[vicratlhead51]

FWIW, I haven't typically noticed yeast stress from low fermentation temperatures, but from sudden temperature drops. I ferment most of my beers at the very low end of the yeast's range and I get relatively long fermentations, but I think I get a cleaner final product for it. An even temperature is, in many respects, more important than a specific temperature.

Gotcha. I should be perfectly safe then. It stays really steady down there and you're right the few batches I've made this winter have come out really clean tasting and a lot clearer too. Takes longer to bottle condition though. Too bad I really don't have any space upstairs but if there's one thing this hobby has taught me it's that patience is well rewarded.

 

[theredben]

Scholarly
Commercial
I bought one (at the recommendation of the recipe on the yeast package). I'll do a very unscientific before and after taste test and post the results. If anyone knows some inexpensive way of measuring fusel oils or undesirable fermentation byproducts, I'd be happy to measure the results.

Hate to burst your bubble, but unless you are looking to remove fusels from distilled spirits (which I hope not, because that is illegal) then your links are not pertinent. There is a big difference between removing impurities from something that is 40% ABV, when looking for clean alchohol and something that is ~5% ABV and looking for a final product full of flavour compounds.

Also I would not trust anything on the "Leeners" website. Activated charcoal works by absorbing reactive compounds, not filtering them based on molecule size. That is total junk science.

 

[ancapgeko]

Hate to burst your bubble, but unless you are looking to remove fusels from distilled spirits (which I hope not, because that is illegal) then your links are not pertinent. There is a big difference between removing impurities from something that is 40% ABV, when looking for clean alchohol and something that is ~5% ABV and looking for a final product full of flavour compounds.

Also I would not trust anything on the "Leeners" website. Activated charcoal works by absorbing reactive compounds, not filtering them based on molecule size. That is total junk science.

I work in water treatment and you are not quite right about how activated carbon works. Activated Carbon doesn't "absorb" anything. It "adsorbs" things. Depending upon the form of the activated carbon it does work by filtering out impurities based on molecule size. Granulated activated carbon essentially looks like a sponge, when water passes through a filter of GAC then the larger molecules (like water) go around the granules while the smaller molecules (impurities) become trapped in the crevices and spaces of the GAC.
GAC can become saturated with these impurities and need to be backwashed to remove them, but that is how it works.

 

[theredben]

I work in water treatment and you are not quite right about how activated carbon works. Activated Carbon doesn't "absorb" anything. It "adsorbs" things. Depending upon the form of the activated carbon it does work by filtering out impurities based on molecule size. Granulated activated carbon essentially looks like a sponge, when water passes through a filter of GAC then the larger molecules (like water) go around the granules while the smaller molecules (impurities) become trapped in the crevices and spaces of the GAC.
GAC can become saturated with these impurities and need to be backwashed to remove them, but that is how it works.

You are definitely correct about the adsorb thing, I always mix up the two.

Regarding the filter question, we are not talking about a pressurized system here, only gravity flow, so there is now way it is filtering anything like a micron scale. If you look at the system it looks like/says that it is for distilled alchohol. Not for beer.

 

[MalFet]

I work in water treatment and you are not quite right about how activated carbon works. Activated Carbon doesn't "absorb" anything. It "adsorbs" things. Depending upon the form of the activated carbon it does work by filtering out impurities based on molecule size. Granulated activated carbon essentially looks like a sponge, when water passes through a filter of GAC then the larger molecules (like water) go around the granules while the smaller molecules (impurities) become trapped in the crevices and spaces of the GAC.
GAC can become saturated with these impurities and need to be backwashed to remove them, but that is how it works.

Any chance I could pick your expert brain? What kinds of things would be filtered out by either carbon or mechanical filtration? My understanding was that fusels (for example) wouldn't be, but I'd love to hear something from somebody with background in the issue.

 

[Calder]

I ferment most of my beers at the very low end of the yeast's range and I get relatively long fermentations, but I think I get a cleaner final product for it. An even temperature is, in many respects, more important than a specific temperature.

Fermenting at different temperatures will give different results, so the temperature is important. Lower temperatures tend to result is less esters. But if you are using an English or Belgian (and probably others too), you will not get the wonderful flavors typical of that yeast by fermenting low. You really should be aiming for the top of the range ......... but you need to be careful that the self heating effect of the yeast does not push you above the max temperature.

 

[Wyrmwood]

unless you are looking to remove fusels from distilled spirits

It works the other way around. You filter fermented spirits to remove fusel oils, then (if you were commercial/licensed and wanted to increase alcohol content beyond what fermentation is capable of) you would distill to remove further contaminants and concentrate the solution.

 

[cklages]

I work in water treatment and you are not quite right about how activated carbon works. Activated Carbon doesn't "absorb" anything. It "adsorbs" things. Depending upon the form of the activated carbon it does work by filtering out impurities based on molecule size. Granulated activated carbon essentially looks like a sponge, when water passes through a filter of GAC then the larger molecules (like water) go around the granules while the smaller molecules (impurities) become trapped in the crevices and spaces of the GAC.
GAC can become saturated with these impurities and need to be backwashed to remove them, but that is how it works.

Sorry, no sale. A Fusel would be a significantly larger molecule than the lowly H20.

I hate to rip off wikipedia as they can be a little dubious on their facts, but

Physically, activated carbon binds materials by van der Waals force or London dispersion force.

Activated carbon does not bind well to certain chemicals, including alcohols, glycols, strong acids and bases, metals and most inorganics, such as lithium, sodium, iron, lead, arsenic, fluorine, and boric acid.

On top of all of this here is a link to an animal study which seems to indicate that the presence of fusel oils actually managed to decrease the apparent 'hangover' symptoms present in lab animals, and actually made hangover symptoms better.

http://www.ncbi.nlm.nih.gov/pubmed/12960505

okay...discuss

 

[ancapgeko]

Sorry, no sale. A Fusel would be a significantly larger molecule than the lowly H20.

Not selling anything, but thanks. I wasn't trying to say that the filter system that was linked to would work (I didn't even follow the link) I was really just being bitchy about the "absorb" vs. "adsorb" semantics.

"Any chance I could pick your expert brain? What kinds of things would be filtered out by either carbon or mechanical filtration? My understanding was that fusels (for example) wouldn't be, but I'd love to hear something from somebody with background in the issue."

I'm not going to claim I'm an expert (I'm not, I'm only an operator at an industrial water treatment plant), but I will say this. I don't think that carbon filtration of the beer would be advisable unless you used a new sterilized filter for every batch. Because of the adsorbtion process and the fact that contaminates would build up quickly the carbon would go bad real quick.
There is one possibility, I don't know if it would work but its worth a test.
One method of removing volatile organics in water is by means of air stripping. It mostly works with organics that don't easily dissolve in water so fusels don't fit the bill exactly, and you wouldn't want air to do the stripping. But you could hook up your oxygen stone to CO2 and stick it into your brite tank. Let that rip for a while (not sure how long) and see if any of the fusel alcohols were stripped off in the process.
Again, to everyone, I have no idea if this will work or if it's just crazy drunk talk. Please don't tell me your not buying.

 

[vicratlhead51]

Which molecules are bigger the fusels (or is it fusals? I've seen both) or the good ethanol we want in our beer? Seems like that'd be key on how to remove them. I believe in both sides of the argument that they can be removed, filtering or by the air stripping, but don't you run the risk of removing the good stuff at the same time? BTW what a great profession to have for making beer, water treatment, I bet you've really got water adjustments down to a science. My dad's in water treatment too and I've picked his brain a few times but since he doesn't brew he doesn't always quite get what I'm talking about.

 

[coastwx]

FWIW, I haven't typically noticed yeast stress from low fermentation temperatures, but from sudden temperature drops. I ferment most of my beers at the very low end of the yeast's range and I get relatively long fermentations, but I think I get a cleaner final product for it. An even temperature is, in many respects, more important than a specific temperature.

Yeah, I just had two big beers (1.085) ferment out at 61F with S-05. The weather kept the temp almost perfectly steady in my brew closet for the first 14 days. It took 20 days to get down to 1.010, but the sample yesterday was of probably my cleanest beer to date.

 

[theredben]

Which molecules are bigger the fusels (or is it fusals? I've seen both) or the good ethanol we want in our beer? Seems like that'd be key on how to remove them. I believe in both sides of the argument that they can be removed, filtering or by the air stripping, but don't you run the risk of removing the good stuff at the same time?

Fusel Oils are by definition bigger, they have one extra carbon atom. But you are correct in assuming that removing things in the size range of fusels will remove flavour compounds. You cannot filter beer on that level and still have beer come out the other end. But this product does not work by filtering based on size, it works with adsobtion.

There seems to be no recognition in this thread that there is no scientific proof that fusels cause any problems, in fact they are a key component of the flavour profile of many beers.

 

[ancapgeko]

I'm sure most here would agree that fusels are part of the flavor profile of many beers, in fact are the defining characteristic in some styles.
However, I think it is entirely appropriate to discuss methods to reduce certain unwanted characteristics.

 

[MalFet]

There seems to be no recognition in this thread that there is no scientific proof that fusels cause any problems, in fact they are a key component of the flavour profile of many beers.

Uhh...what? My scientific proof is that when I drink beers with excessive fusels they taste bad.

I don't think anybody here has suggested that fusels are all bad all the time, but excessive fusels is a real problem that people run into.

 

[theredben]

MalFet - I meant "bad fusels" in the respect that people believe them to cause hangovers. I completely understand not liking the taste of butanol , but unfortunately it seems we are stuck with them.

 

[vicratlhead51]

Fusel Oils are by definition bigger, they have one extra carbon atom. But you are correct in assuming that removing things in the size range of fusels will remove flavour compounds. You cannot filter beer on that level and still have beer come out the other end. But this product does not work by filtering based on size, it works with adsobtion.

There seems to be no recognition in this thread that there is no scientific proof that fusels cause any problems, in fact they are a key component of the flavour profile of many beers.

Yeah we kind of got off track a bit. I started the thread because a coworker asked if my homebrews ever gave me a headache. I assumed it would be overproduction of fusels but I was also curious if there were any mistakes somebody could make to brew a beer that caused bad hangovers or headaches. I'd love to hear any other reasons or causes.

 

[theredben]

All the evidence says that the most important factor in hangovers is the way you drink. Drink a beer with a glass of water before the next one and you will be better off regardless of what is in the beer.

 

[cklages]

There are numerous theories on what actually causes hangovers, here is a website that disusses a bunch of them:

http://hamsnetwork.org/hangover/

The one that I kind of subscribe to is the following

The Congener Hypothesis
Congeners are chemical compounds other than alcohol and water which are found in alcoholic beverages and which contribute to giving them a pleasing color and flavor and smell. Examples of typical congeners are amines, amides, acetones, polyphenols, methanol, and histamine.
In 1970 Dr. LF Chapman did an experiment to see whether congeners increase the likelihood of people having hangovers. Dr. Chapman gave one group of subjects bourbon whiskey, a beverage which is very high in congeners. Another group of subjects were given vodka which is very low in congeners. Both groups were given the same dosage of alcohol (1.5g/kg). 33% of the subjects who received the bourbon reported hangover, whereas only 3% of subjects who received vodka reported hangover.
There are a couple of studies (Woo et al, 2005, Bendtsen et al 1998) which suggest that the congener methanol may be involved in hangover. Methanol is also known as methyl alcohol or wood alcohol and is a highly poisonous compound which can cause blindness or death. The human body breaks methanol down into the toxic components formaldehyde and formic acid. Trace amounts of methanol are found in alcoholic beverages, but they are also found in orange or apple juices.
In order to test the hypothesis that methanol is responsible for hangover it would be necessary to conduct the following experiment: a mixture of pure ethanol and water would need to be compared to a mixture of ethanol and water which contained a trace of methanol and both of these should be compared to water containing a trace of methanol. If such an experiment were conducted it would work to confirm or disconfirm the methanol hypothesis of hangover. There are several other congeners which are also hypothesized to contribute to hangover, including isopentanol, ethylic acetate, and ethyl formate, etc. The hypothesis that these congeners contribute to hangover could be tested the same as the methanol hypothesis above. Such experiments have yet to be carried out.

 

[MalFet]

All the evidence says that the most important factor in hangovers is the way you drink. Drink a beer with a glass of water before the next one and you will be better off regardless of what is in the beer.

Hydration is certainly a part of the issue, but there is significant evidence to suggest that various kinds of toxicity are also at play. This article suggests that acetaldehyde is partly to blame. This article talks correlates hangover duration to rates of methanol metabolization. There are tons of other papers out there that identify other potential metabolites.

As for fusels: There is a lot of anecdotal evidence to suggest that beers with high fusel levels lead to headaches, but there isn't much evidence to back it up one way or another. One paper did explore the issue and even found that fusels lead to decreased headaches in mice (supposedly), but their sample was very small and I found their methodology a bit suspect. There is enough anecdotal evidence (including my own) correlating fusels and headaches that I'm still somewhat convinced by the link, but I'd don't think there is decisive info one way or the other.

The move to realize that dehydration is an important factor in hangovers certainly appears to be correct, but I would hesitate to say that it is "the most important factor" without some evidence. I've not seen anything that ranked these things, but would love to read anything you might have seen that says otherwise.

Edit: Good find cklages. The bourbon vs. vodka thing is very suggestive. Unfortunately, the decisive research has not yet been carried out, and (thanks to university IRB boards) likely never will be.

Edit2: One thing in favor of hydration, at least, is that it is something you can control. You can't easily make your kidneys or liver metabolize toxins faster, but you can make yourself have a big glass of water before you go to bed.

 

[theredben]

MalFet - While it would seem from my reply that I was infering that I think dehydration causes hangovers, what I really meant was that it both reduced the physical amount of beer you can consume and spread it out over a longer period of time. Same thing as drinking a big glass of water 30 minutes before a meal. No special chemical sequences, just less physical space for food.

I will see if I can find the link an interesting report on wine consumption. Seems that people say that when they go to europe they don't have a hangover afterwards, obviously because the wines are far superior /superiority complex. But when they look into the issue, people can drink the exact same bottle of wine in North America and get totally wasted, but it is mainly due to the way that it is consumed.

Found what I thought to be the link, but it doesn't seem to cite anything, I'll keep reading. The information about comsumption style is about 2/3 of the way down.

 

[theredben]

cklages - slightly off topic, but holy cow! 1.5g/kg of alchohol.

average person =~72kg x 1.5g = 108g alchohol. Spirits are 40% so, 108/0.4=
270g vodka/brandy. Given that with the alcohol it will be a little bit lighter than water you are still looking at around 3/4 cups!!!

 

[MalFet]

I will see if I can find the link an interesting report on wine consumption. Seems that people say that when they go to europe they don't have a hangover afterwards, obviously because the wines are far superior /superiority complex. But when they look into the issue, people can drink the exact same bottle of wine in North America and get totally wasted, but it is mainly due to the way that it is consumed.

Found what I thought to be the link, but it doesn't seem to cite anything, I'll keep reading. The information about comsumption style is about 2/3 of the way down.

I don't think anyone would dispute that hydration and manner of drinking is an important factor. But, I do think that people dismiss the importance of toxicity far too quickly these days. The proverbial baby got thrown out with the bath(tub gin), as it were.