Removing Fusels - an experiment

[hububalli]

Hi,
I have a standard session ale that I am pretty certain has fusel alcohols in. It is about 6 months old now and tastes pretty decent apart from the throat burn, and strange after taste. I was going to chuck it down the drain but thought it might be worth experimenting with, just to see what happens.

I want to boil it up to remove the fusels (and all the good alcohol too obviously) ,add some brewing sugar and repitch.

Is it possible to boil off all the fusel alcohol? I understand that alcohol will boil off at around 78c.

I know that even if it works it will change the flavour profile considerably but I am still curious to try it.

 

[Calder]

Sounds awful and like hard work.

I hope you will be boiling outside. At 5% abv, that would be half a gallon of pure alcohol you will be boiling off from a 5 gallon batch. You will need to ensure it is vented outside or it could be very explosive.

 

[1977Brewer]

No need to boil, just hold it at 175 for a while.


Are you super attached to the beer or just flat broke? Keep it and use it to cook with. You have to know a drunk with low standards, give it to them...anything but trying to boil out the alcohol.

 

[day_trippr]

Sounds awful and like hard work.

I hope you will be boiling outside. At 5% abv, that would be half a gallon of pure alcohol you will be boiling off from a 5 gallon batch. You will need to ensure it is vented outside or it could be very explosive.

Actually, a quart, more or less. Still, I suppose given the right conditions there would be a period where a flash-over could indeed happen...

Cheers!

 

[Calder]

Actually, a quart, more or less. Still, I suppose given the right conditions there would be a period where a flash-over could indeed happen...

Thanks for correcting me. A quart is still a large amount of pure alcohol.

 

[doug293cz]

Also, some of the fusels probably have boiling points higher than than ethanol and water, so boiling will not work.

Brew on

 

[snow16]

If you're successful in removing fusel alcohols, I'm confident that you'll also be successful in removing 100% of the beer's finer qualities right along with them.

Right now you have a beer that is not perfect, but perfectly drinkable. I bet most of us have at least one of those in our home breweries at the moment.

In my opinion, drink it as is (or cook with it, whatever) and learn from it.

 

[vincentAlpha]

+1 to cooking with the beer. I've got a stout on tap that just... well long story but it is what I drink after I've had a couple of the good stuff. Though it makes for AWESOME bread, I've been adding it 50/50 to water for my recipes as of late and may just try the next batch 74/25 or 100% beer vs. water to use it up.

 

[butterpants]

Extended ageing is the only way I've removed fusels. 6-12mo in a few belgians I've gotten overzealous with far as ferm temps go and drying them out. FYI, I've always been successful but they were all substantial beers, not 5%.

Give it another 6 mo and if it's still present, dump it.

 

[ol-hazza]

I would hate to waste the alcohol, perhaps collect it as you boil it off and then store it in a barrel and then water it down a bit and then drink it.

We could call it whiskey!!

 

[BrotherGrim]

I had a 5 gal batch with the same issue. I had already kegged it and it was terrible right after carbonation. I took the keg off the tap and shuffled it to the back. I left it there until I had an empty tap with nothing else to put on it, and decided to try it again. It had been about 4 or 5 months just setting there and turned into a lovely beer. It was not what I had planned, but it was definitely drinkable.

 

[JohnSand]

I don't think I've ever heard of such an experiment. I woulds be interested in your results.

 

[hububalli]

Thanks for all the comments!

It is far from drinkable unfortunately. At first it is very pleasant but then the burn hits and it lasts for hours after, even from just a sip. I kept it for 6 months in the hope that it would sort it self out but its not getting any better with age. I am not one for just accepting things, I would prefer to ruin it all in the hope of fixing it/learning something. I also like experimenting with stuff so this is a good chance to do that!

What 1977Brewer said was what I read somewhere so that's what I did, on a small scale anyway. I did have concerns about creating a fireball in my kitchen so yeah, I did it outside. I just took a large saucepan and half filled it. kept it at 80C 175F for 30 minutes, then let it cool. While it was at temperature the smell coming off the beer was exactly the same as the bad taste, so obviously it was evaporating.

Once it cooled I tasted it and I am pretty pleased. The burning sensation has gone completely. It tastes like low alcohol beer now, there is definitely alcohol still in there, the good kind too as far as the taste goes. The flavour profile is not as complex as it was but I am not sure if this is just down to the low alcohol content. At no point did it boil though, so that might have saved destroying the flavour.

I will be doing the rest of it sometime in the next few days I hope.

 

[ChelisHubby]

Thanks this is good to know that it can be done at least with some Fusels. Please update with your results of this experiment!

 

[douglasbarbin]

The boiling point of ethanol ("good" alcohol) is around 173F / 78C, somewhere in that range. The fusel alcohols have much higher boiling points, all of them well over 200F. The two main fusels are isopentyl (~260F) and isobutyl (~220F) although others can be present. Those are not the exact boiling points but they are in that general range.

So if you were to to distill your beer, you would collect, in this order:

1. methanol
2. ethanol
3. water
4. fusels

Similarly, if you were boiling them off, they would leave the mixture in that same order. Basically you would be left with water, fusel alcohols, hops, and your various residual sugars as well as any spices you might have added. It would probably be undrinkable, assuming that there was a noticeable amount of fusels present in the first place.

Glad to hear that you fixed your beer, but my guess is that you had another off-flavor that you boiled off instead of fusel alcohols. Possibly some other unpleasant alcohol, although not technically a fusel. Fusels would still be in there at that temperature, and you would have no ethanol left at all.

EDIT: There is a reference at http://www.engineeringtoolbox.com/boiling-points-fluids-gases-d_155.html that may be helpful.

 

[hububalli]

Thanks! I will certainly update the thread with how it goes on the rest of the batch.

Thanks for that information Douglasbargin, it is interesting to see that I was no where near removing the fusel groups of alcohols.

The off taste of the beer is like cheap spirit. Rough, burning and long lasting on the throat. If it is not a fusel alcohol that is being removed, I wonder what it is.

 

[JohnSand]

I am not any kind of scientist. But just because something doesn't boil, doesn't mean it didn't evaporate. If warmed long enough, all of the liquids would leave your beer. You may have evaporated the fusels just by warming.

 

[hububalli]

That's a good point. Brandy looses something like 1% of its alcohol a year just sitting in the bottle. You also get steam quite quickly when heating water, way before you reach boiling point. The fumes coming of it certainly were burning the inside of my nose!

 

[douglasbarbin]

I am not any kind of scientist. But just because something doesn't boil, doesn't mean it didn't evaporate. If warmed long enough, all of the liquids would leave your beer. You may have evaporated the fusels just by warming.

That wouldn't have happened without evaporating all the other liquid first. Fusels would be the last to leave the kettle. They still require a higher temperature than ethanol, water, etc. to begin evaporating. It's much more likely that he evaporated methanol, ethanol, isopropyl, etc.

 

[ajdelange]

I am not any kind of scientist. But just because something doesn't boil, doesn't mean it didn't evaporate.

Yes, it more or less does. Over any liquid there is vapor which is a mix of the vapors of all the species in the liquid, in this case water, ethanol and each of the fusel alcohols. It is the amount of each that determines how much is removed if the vapor is swept away. The concentration of each species depends on its vapor pressure and its concentration in the liquid. Thus at 78 °C where the vapor pressure of water is about 0.4 atm but that of ethanol is 1 atm (the boiling point of a substance is the temperature at which its vapor pressure is 1 atm.) and the vapor pressures of the fusels is appreciably lower (their boiling points are higher) the vapor is mostly water (because even though the vapor pressure of ethanol is higher its mole fraction in the liquid is small compared to that of water) but it is quite rich in ethanol (perhaps 20%) but rather poor in the fusels. In distilling the column is there to condense the water and return it to the mash while allowing the alcohol vapor to pass to the condenser.

Thus while it is true that if you can smell what you are after in the vapor that is proof positive that it is in the vapor the amount in the vapor is small and you won't remove much of it unless you go to higher temperature and boil away most of the liquid (higher temperature gets you higher vapor pressure and reduced volume gets you higher mole fraction). As an example of this, when assaying alcohol in beer we boil away two thirds of the beer in order to be sure we get all the ethanol. Even so we only get about 99% of it. And now to the most important part of this. Even though we went for the ethanol and thus never exceeded 100 °C what is left in the flask is pretty unappetizing stuff! I would in no way consider even tasting it it smells so bad, let alone drink it.

If warmed long enough, all of the liquids would leave your beer.

That's true. But see remark above about what's left after you remove two thirds.

You may have evaporated the fusels just by warming.

You will have removed some fusels but most will still be in what's left of the beer.

 

[JohnSand]

And yet it still worked.

 

[ajdelange]

Well it fixed the beer but it didn't remove the fusels. He didn't even heat it enough to remove all the EtOH. He, therefore, cannot have removed more than a small amount of anything substantially less volatile than EtOH (fusels). What he did remove are things more volatile than EtOH and it is, thus, these that were clearly responsible for the problems. The volatiles associated with jungbuket come to mind though I don't know of any of those being responsible for a persistent burning sensation.

The practice of removing volatiles from 'beer' has long been carried out and is well understood. Beer is in quotes here because that's what a distiller calls his mash. He will separately collect the 'heads' (the less volatile nasty stuff - what OP drove off here) and 'tails' (the fusels) and sell them to chemical producers who separate, purify and sell the fusels from the latter and methanol from the former.

 

[JohnSand]

Thanks for the interesting information.

 

[hububalli]

I agree JohnSand, this has been a really interesting thread, There has been some really detailed information that is really useful.

I just had a smell of some 70% Rubbing Alcohol I have and there is quite a similarity to the smell from this to the smell coming off the beer when hot, I am not going to try the taste test though! I think this matches what Ajdelange was saying about removing the more volatile alcohols.

I transferred the whole batch to my kettle and got it up to temperature yesterday. I left it for 1h15min in the end, the smell had considerably lessened by that time. I ran it through my wort chiller this time too. I will add that the fumes coming off it where very strong. It hurts your nose, eyes and you could taste it, so if you copy this do it outside!

After it was cooled it tasted very similar to the test batch, watery, but nice beer. I think it had slightly less "good" alcohol left than the test batch though, as it was slightly thinner in taste. Maybe I could have got away with slightly less heating time. I boiled 1kg of DME in a little water and added that in (decided on this instead of just brew sugar to balance out any damage the heating might have done to the flavour), a little yeast nutrient (not sure its really needed with the DME but just being sure) and pitched the yeast. Today its got a nice krausen forming and it smells as it should at this point.

Will leave that for a while and post an update here later on. It has been a reasonable amount of effort but personally, if it works out, I think its worth it to save waste and to learn something new. I also only have the space to own 2 kegs so it was make or break time for this batch!

 

[JohnSand]

I'm glad you tried, and succeeded. A big part of the fun is experimenting and learning. I re-hopped an older IPA in the bottles. That worked too.