Separating ethanol from methanol

[gatewood]

I just distilled a bit of my homebrew for experimentation and I was wondering of someone here has had experience and has been successful at separating ethanol from methanol. How can I do it? Just by fractional distillation?

 

[dwhite60]

Why do you want to do this?

The cure for methanol poisoning is to immediately consume some ethanol. Just cancels it out.

You certainly have more ethanol in your runnings than methanol. I wouldn't stress on it.

All the Best,
D. White

 

[tummydoc]

You likely have minimal methanol in an all grain brew. More typical in a fruit ferment.

 

[gatewood]

Why do you want to do this?

The cure for methanol poisoning is to immediately consume some ethanol. Just cancels it out.

You certainly have more ethanol in your runnings than methanol. I wouldn't stress on it.

All the Best,
D. White

You likely have minimal methanol in an all grain brew. More typical in a fruit ferment.

I'm trying to do some chemistry experiments and it'll be quite handy to be able to produce pure ethanol/methanol.

Anyhow, thanks for the advice ppl

 

[Abhishek Dewan]

Distillation is the way to do it.

 

[Contrarian]

Distillation is the way to do it.

Not really, if you have a 50% mix of Ethanol/methanol simple distillation may get you part of the way but will never give you something safe to drink.

In distillation it's generally the other congeners that we really care about removing/balancing.

For a natural ferment without adulterants methanol isn't really a concern. Historically methanol poisoning is from the addition of methanol somewhere in the process, not failure to remove it from a natural ferment.

 

[Contrarian]

I'm trying to do some chemistry experiments and it'll be quite handy to be able to produce pure ethanol/methanol.

Anyhow, thanks for the advice ppl

Pure methanol - you are going to have to buy it, you can't produce enough or at high enough concentration easily.
Simple distillation may get you pure enough ethanol for some purposes but that depends on your tolerance to other compounds.

 

[Gnomebrewer]

With a good reflux still it's very easy to separate the bulk of the methanol from ethanol from a wash. But, as mentioned already, it's all the other stuff that's the problem so you won't get 'pure' methanol and 'pure' ethanol. The methanol component is quite small and comes through at the same time as some other nasties like acetone. Ethanol from a good reflux should be more pure than the methanol, but will still have trace amounts of other stuff, and (unless distilled in a vacuum) at least about 5% water. A very high-end still might be more able to precisely split the fractions, but not at a home level.

 

[Gnomebrewer]

if you have a 50% mix of Ethanol/methanol simple distillation may get you part of the way but will never give you something safe to drink.

If I had a 50/50 mix of Ethanol/methanol I'd be very confident of being able to separate it with a decent reflux or column/plate still (not with a pot still) and water (needed to help separate the ethanol and methanol.......steam in the column should help break the bond between ethanol and methanol) to a point that I'd expect to need to 60% then keep the final 40%. I'd definitely test whatever I was going to drink for methanol first though!

 

[Vale71]

I just distilled a bit of my homebrew for experimentation and I was wondering of someone here has had experience and has been successful at separating ethanol from methanol. How can I do it? Just by fractional distillation?

Since there is no methanol in beer (not even trace amounts) there is nothing you can or need to do about it.

 

[bernardsmith]

Hi gatewood. To answer your question I would approach the problem this way: don't methanol and ethanol have different boiling points? At what temperature does methanol boil? I think at 148.5 F. At what temperature does ethanol? I think at 173.1 F. Presumably using those data points would provide you with the means to collect methanol. In other words, if you maintain the temperature of your wash at 148.5 F and don't exceed, say, 160 F any methanol in any wash should become gaseous and so travel up through the condenser and be collected as it condenses. A temperature of 160 F is too low to boil ethanol.

 

[Gnomebrewer]

Since there is no methanol in beer (not even trace amounts) there is nothing you can or need to do about it.

Would you have a source for that? I was under the impression there was somewhere around 10ppm.

 

[Gnomebrewer]

Hi gatewood. To answer your question I would approach the problem this way: don't methanol and ethanol have different boiling points? At what temperature does methanol boil? I think at 148.5 F. At what temperature does ethanol? I think at 173.1 F. Presumably using those data points would provide you with the means to collect methanol. In other words, if you maintain the temperature of your wash at 148.5 F and don't exceed, say, 160 F any methanol in any wash should become gaseous and so travel up through the condenser and be collected as it condenses. A temperature of 160 F is too low to boil ethanol.

It's not quite that simple. Methanol and Ethanol form an azeotropic mixture, meaning they don't want to evaporate at their individual boiling points, they act as a single liquid. You need water/steam and time refluxing to break them apart (actually, the water will replace the methanol as the azeotrope with the ethanol). Simply heating to 160F doesn't work.

 

[RPh_Guy]

Would you have a source for that? I was under the impression there was somewhere around 10ppm.

Kunze 6th English Ed. p710.
"No methanol is produced during alcoholic fermentation in beer."

 

[bracconiere]

Hi gatewood. To answer your question I would approach the problem this way: don't methanol and ethanol have different boiling points? At what temperature does methanol boil? I think at 148.5 F. At what temperature does ethanol? I think at 173.1 F. Presumably using those data points would provide you with the means to collect methanol. In other words, if you maintain the temperature of your wash at 148.5 F and don't exceed, say, 160 F any methanol in any wash should become gaseous and so travel up through the condenser and be collected as it condenses. A temperature of 160 F is too low to boil ethanol.

the ethanol might not be "boiling", but i'd assume it was evaporating quickly....


edit: i know when i have my washes at 170-180 well under the boiling point of water, i only get like 70-80% pure ethanol....

 

[bracconiere]

honestly if you need pure methanol...

https://www.ebay.com/itm/99-85-Pure...hash=item3649bfcc09:m:m9Wj9daCrX_Lk9AtcJin8Uw

 

[bernardsmith]

edit: i know when i have my washes at 170-180 well under the boiling point of water, i only get like 70-80% pure ethanol....

OK so two quick thoughts - 1. What was the ABV of the wash and how much distillate are you collecting? Presumably the more distillate you collect the lower the proof of what you collect, and

Water might boil at 212 but water mixed with ethanol boils at a far lower temperature. This is known as an azeotrope and the BP of this azeotrope is closer to 172.76 - so keep the temperature of the wash closer to 160 if you don't want the ethanol-water mix to boil...

 

[bracconiere]

OK but what was the ABV of the wash and how much distillate are you collecting? Presumably the more distillate you collect the lower the proof of what you collect, no?

i usually start with 16% wash, start collecting 85% at first, then callit quits when it hits about 50% or so, for a gallan of cask strength off of 6 or so gallons of wash...i can pull 92% with my refulx column, but there's a such thing as aziotropes(SP?).....to get 100% i'd have to use molecular sieves or something like that....

speaking of molecular sieves, i think you could separate the methanol from ethanol using them....

 

[Gnomebrewer]

Kunze 6th English Ed. p710.
"No methanol is produced during alcoholic fermentation in beer."

According to the world health organisation, 6 to 27mg/L methanol has been measured in beer. It's a natural byproduct of alcoholic fermentation. From International Programme on Chemical Safety . Environmental Health Criteria No 196: Methanol. Geneva : World Health Organization, 1997.
In this (very rare) case, I think Kunze is wrong.

 

[bracconiere]

so on the high side of 27mg/L wouldn't that be like 0.0008%...and not a good way to get pure methanol for a science project? lol

 

[bracconiere]

and the only chemistry i can imagine is making esters....and molecular sieves are they way to go...can the OP elaborate?

 

[Gnomebrewer]

so on the high side of 27mg/L wouldn't that be like 0.0008%...and not a good way to get pure methanol for a science project? lol

Definitely not, as has been said several times. It's only a trace amount.

 

[Gnomebrewer]

Also, just in case somebody reads this with the intention of separating methanol from ethanol from methylated spirits/denatured alcohol/denatured rectified spirit for the purpose of drinking......

There are other additives to metho to make it poisonous and foul tasting. At a home level, it is virtually impossible to separate out the poisons, so don't try it!

 

[bracconiere]

I just distilled a bit of my homebrew for experimentation and I was wondering of someone here has had experience and has been successful at separating ethanol from methanol. How can I do it? Just by fractional distillation?

I'm trying to do some chemistry experiments and it'll be quite handy to be able to produce pure ethanol/methanol.

Anyhow, thanks for the advice ppl

just thought i'd clarify it.....

 

[Vale71]

It's a natural byproduct of alcoholic fermentation.

No it isn't. Yeast just has no methabolic pathway for the production of methanol and barley malt lacks the precursor, pectine.
If they measured those trace amounts in commercial beer then a contamination, either upstream or downstram, must be the cause. Possibly some non-malted adjunct or some process additive.

 

[Gnomebrewer]

Hmmmm. Vale71 from the internet vs the World Health Organisation?

 

[Vale71]

Sorry but the WHO is saying they detected methanol in trace amounts in beers they analyzed. You're the one claiming that it comes from fermentation and you're the only one making that claim for a good reason and that's because you're wrong.
If you can find a metabolic pathway for methanol in this very up to date resource please let us know...

 

[bracconiere]

settle down now boys....the OP wanted to know if he could get methanol from distilling beer.....at .0008% probably not....

hmmm, here's something from a possible science site...lol, DMT huh....


https://www.dmt-nexus.me/forum/default.aspx?g=posts&t=3398

 

[RPh_Guy]

According to the world health organisation, 6 to 27mg/L methanol has been measured in beer.

Following the trail of citations leads back to a single article from 1981, which is still behind a paywall.
https://www.jsad.com/doi/abs/10.15288/jsa.1981.42.1030?journalCode=jsa

Without the details of the article I think it's a little difficult to try to extrapolate this claim to all beer.
For instance did some of the measured beer contain fruit or contaminants of some kind?

As an example here's an article that references the detection methanol in a single "beer" in Rwanda made from banana:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5028366/
This article says specifically that methanol comes only from pectin and cites several sources.

If you can find a metabolic pathway for methanol in this very up to date resource please let us know...

How is methanol produced in fermentations with pectin?

 

[Gnomebrewer]

Sorry but the WHO is saying they detected methanol in trace amounts in beers they analyzed. You're the one claiming that it comes from fermentation and you're the only one making that claim for a good reason and that's because you're wrong.
If you can find a metabolic pathway for methanol in this very up to date resource please let us know...

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5028366/
This article describes the process quite well. "Methanol is produced during fermentation by the hydrolysis of naturally occurring pectin in the wort". Grains only contain very small amounts of pectin, so the methanol content of beer is very small (hops also have pectin which would contribute to methanol in beer). Fruits obviously have much more pectin, hence more methanol in wine/cider.