ABV dependent volatility of fusel oils

[Bagasso]

Thanks, Bagasso and Zapata, very helpful.

I'm sure that if you can make it look like one of those solar water heaters that have become popular you can avoid the paranoia of having a still out in the open. They are even plumbed for water water cooling wouldn't even raise suspicions if you can get it efficient enough to need water cooling..

[zapata]

You sure could. But mine looked like a hillbilly cooking methwhiskey!

So it just occurred to me this thread explains well the difference between pot still tails and reflux tails. It's not that they are just more concentrated as many a flute runner has stated, and I've thought myself with column distilled whiskey. It's that the components concentrated are different.

In the rum realm this also makes things tough for anyone reading Arroyo and trying to replicate with a pot or thumper setup. His fraction 3 wouldn't exist without pretty high reflux, and who knows about his later fractions since so far as I know they were never identified. Might be the discrepancy between some people not putting any stock in rum oils vs those who do.

[Bagasso]

In the rum realm this also makes things tough for anyone reading Arroyo and trying to replicate with a pot or thumper setup. His fraction 3 wouldn't exist without pretty high reflux, and who knows about his later fractions since so far as I know they were never identified. Might be the discrepancy between some people not putting any stock in rum oils vs those who do.

What is special about Arroyo's fraction 3. Looked it up but only came up with a person's site where they have been working using his technique. Two things that stood out where:
1) The only protocol Arroyo spells out in Studies on Rum is the distilling of 250 ml of 40% ABV distillate, but that isn’t likely the only protocol he used. 250 ml * .40 means that there is 100 ml of absolute alcohol in the distilling flask.

2) Fraction 3 is the only fraction that retains any brimstone aroma which is interesting because it is typically the most neutral of all the fractions.

I know it is not from Arroyo but I wonder how it compares. Of course the 40% ABV stands out in regards to the discussion of the thread.

[zapata]

Arroyo did a variety of work with different fractions including a lab style fractional distillation and identified 7 or 8 fractions. From analyzing these fractions he came up with his practical application of collecting 4 fractions. Described in the heavy rum patent, and probably others (simultaneous heavy and light rum maybe?). From the heavy rum patent though he described 4 fractions.
1. Foreshots .5-1% of wash volume
2. Main body 55-60% of total distillate
3. Fussels 10-15% of total distillate
4. Rum oils
He specified batch distillation, efficient reflux condenser capable of full reflux, and an efficient column.
But in a pot still, or even thumper, everything would come off in a different order, volume and ratio. The fusels portion comes over as heads, which would require a much larger heads cut, and there is no telling what would happen to fraction 4, since it was never identified though he speculated it was terpenes.

[zapata]

If you have trouble finding Arroyo's heavy rum patent, it may be Google's fault, not yours.

Hee hee

[Bagasso]

Arroyo did a variety of work with different fractions including a lab style fractional distillation and identified 7 or 8 fractions.

Sorry I didn't put a link to the site I quoted. It seems to be someone who has put a lot of work replicating Arroyo's work. Here is the link:
Boston Apothecary

In regards to your other post, I wasn't looking for a patent but for the book in the quote I posted, "Studies on Rum" but I will give the patent a look as well.

Maybe I'm remembering wrong, because it was a quick overview, but it seems like one of the fractions was split into "cardboard" and "rum oils". I know he, and everyone else for that matter, says part of the late run is tainted with fusels. That is what this thread is about. The thing is that we have all been saying it is fusels when advanced lab tests show that fusels in low ABV charges come off early.

Ask a home stiller what is tails and the answer is usually "foul, bitter, stinky distillate at the end of the run" some might include descriptors like, wet cardboard, wet newspaper, or wet dog and of course dirty socks.

Now, if we look around for what the 4 major fusels smell and taste like we get (caveat: I left out fusely because that is what is in question):
Isoamyl alcohol: (Odor: alcoholic, pungent, etherial, cognac, fruity, banana and molasses), (Taste: fermented, fruity, banana, etherial and cognac)
active amyl alcohol: (Odor: Pungent, fermented, bready, yeasty, winey and solvent-like), (Taste: fermented, bready and cereal with a fruity undernote)
isobutyl alcohol: (Odor: fruity; wine-like), (Taste: whiskey)
n-propyl alcohol: (Odor: alcoholic, tequila, musty, yeasty, sweet, fruity, apple, pear), (Taste: Alcoholic, earthy, fermented, with peanut nutty nuances as well as fruity nuances of apple, pear, bubble gum)

Now, pungent, yeasty, fermented might be earthy but they are not dirty socks.

Ok, the reason I'm even going into all of this is because with my last batch I tried some different things and one of those things was a liquid-liquid extraction on low wines with vegetable oil.

The low wines were a stripped run with all the funk of a stripped run. Solventy and nutty (one of the things that I rarely see people say of any of their distillate).

Basically I took 1 tablespoon of sunflower oil (it was what we had in the kitchen) and mixed it into 1 liter of low wines watered down to 15%. I stirred so that the oil dispersed throughout and, even though much of it would quickly float to the top, there was a haze left throughout. I let it sit until the haze had cleared from the bottom half. I guess you could just wait for it to completely clear and if you have a separation funnel or racking cane just take the cleared low wines.

Something else I found out is that a slightly compressed cotton ball (trial and error needed to get good flow/separation) in a funnel works really good for separating this type of mixture. With a coffee filter I ended up with droplets of oil in the collection vessel. With the cotton even with just the last couple of milliliters of low wines and a lot of oil in the funnel, for some reason, the oil takes forever to make it through the cotton. Made me think of the old felt hat trick.

The results were an overall drop in smell. The most notable was the nutty smell but the solventy smell was also reduced a lot. It really cleaned up a lot. It was just at 15%ABV so I decided to take a sip. Bitter nasty taste.

In theory, the oil added to the low wines combined with the fusels, since in chemistry like dissolves like and then these were removed, along with any other non-polar compounds. To a certain degree of course because nothing is 100%.

It seemed to follow the theory because the solventy nose was almost gone, along with a good amount of the other smells but the bitterness remained. Also, with the nuttiness toned down, a wet paper smell was more noticeable which is what this long spiel was about. Tails might be foul, bitter and stinky but it isn't the fusels, although that is what we have learned to blame.

What about feel?
If rum oils are part of that mix, would it not make sense that other oily feeling substances or maybe even the same in smaller amounts would be present, without necessarily being fusels?

[RippoZero]

I've been reading up on the subject and thought i might chip in. I found this in a study on the subject by Ana Martı´n, Francisco Carrillo, Luis M. Trillo and
Antonio Rosello.

Their goal was to determine the partition factors of the congeners in wine distillation. When chemical engineers do simulations and such for traditional ethanol distillation they assume that the effects the different type of congeners has on each others partition factor is so small that they can be ignored. This is because the congeners are all suspended in a solution made up almost exclusively of ethanol and water. For this reason the K value of congeners is expressed as a function of ethanol concentration in the mixture.

In the study they were nice enough to include functions for mapping out the volativity of the most common congeners. I typed them out in excel for anyone interested.

Code: Select all

Public Function MeRelVol(ethFrac) //Methanol. All units are expressed in moll fraction
      
   MeRelVol = 1.198 * ethFrac ^ 0.207
   
End Function

Public Function PropRelVol(ethFrac)

Const A1 = 0.559
Const t1 = 0.589
Const A2 = 2.458
Const t2 = 0.011
Const a0 = 0.42
Const e = 2.71828
temp1 = 0#
temp2 = 0#

temp1 = (ethFrac / t1)
temp2 = (ethFrac / t2)

    PropRelVol = (A1 * (e ^ -temp1)) + (A2 * (e ^ -temp2)) + a0
    
End Function

Public Function iButanolRelVol(ethFrac)//I-butanol. All units are expressed in moll fraction

Const A1 = 1.104
Const t1 = 0.292
Const A2 = 4.908
Const t2 = 0.011
Const a0 = 0.389
Const e = 2.71828
temp1 = 0#
temp2 = 0#

temp1 = (ethFrac / t1)
temp2 = (ethFrac / t2)

    iButanolRelVol = (A1 * (e ^ -temp1)) + (A2 * (e ^ -temp2)) + a0
    
End Function

Public Function isoButanolRelVol(ethFrac))//Iso-butanol. All units are expressed in moll fraction


Const A1 = 5.002
Const t1 = 0.012
Const A2 = 1.337
Const t2 = 0.172
Const a0 = 0.282
Const e = 2.71828
temp1 = 0#
temp2 = 0#

temp1 = (ethFrac / t1)
temp2 = (ethFrac / t2)

    isoButanolRelVol = (A1 * (e ^ -temp1)) + (A2 * (e ^ -temp2)) + a0
    
End Function

Public Function isoAmylRelVol(ethFrac))//Iso-amyl alcohol. All units are expressed in moll fraction


Const A1 = 1.183
Const t1 = 0.186
Const A2 = 3.754
Const t2 = 0.014
Const a0 = 0.212
Const e = 2.71828
temp1 = 0#
temp2 = 0#

temp1 = (ethFrac / t1)
temp2 = (ethFrac / t2)

    isoAmylRelVol = (A1 * (e ^ -temp1)) + (A2 * (e ^ -temp2)) + a0
    
End Function

Public Function ethylAcetateRelVol(ethFrac)

Const A1 = 10.45
Const t1 = 0.038
Const a0 = 2.8
Const e = 2.71828
temp1 = 0#

temp1 = (ethFrac / t1)

    ethylAcetateRelVol = (A1 * (e ^ -temp1)) + a0
    
End Function

Study DOI: 10.1007/s00217-009-1104-2