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Separating ethanol from methanol

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gatewood

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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

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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

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

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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 :)
 

Contrarian

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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

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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

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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.
 
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Gnomebrewer

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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

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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

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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

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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

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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.
 

bracconiere

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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....
 

bernardsmith

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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

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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

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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

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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

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

Gnomebrewer

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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

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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

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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.
 

Vale71

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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...
 

RPh_Guy

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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

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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.
 
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RPh_Guy

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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.
Do you have a reference showing how much pectin is in grain or hops?
 

RPh_Guy

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Trace/small amounts in grain (the article is mostly about wheat, but also mentions barley).
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3931795/
I read through this article. I think it's pretty clear that even the trace amount of pectin compounds they detected are inaccessible during wort production and are therefore not extracted.

"To increase accessibility to pectic epitopes the sections were treated with lichenase (endo-1,3(4)-β-Glucanase) 40 U/ml (Megazyme International Ireland Ltd) overnight at 40°C and then with endo-1,4-β-Xylanase M6 (Megazyme International Ireland Ltd ) 50 U/ml overnight at 40°C in water."
"When the grain sections were incubated with both enzymes, LM20 epitopes were detected in the grain outer layers as well as in the starchy endosperm cell walls (Fig. 1F) whereas when only one enzyme treatment was applied (lichenase only or xylanase only), no labeling was observed in the endosperm (Fig. 1D and Fig. 1E)."

Without the use of their highly specific combined enzymatic degradation, there hasn't been any pectin detectable in grain.
"Until now, no pectin has been reported in wheat grain. In early biochemical studies, the polysaccharide composition of wheat flour, which corresponds approximately to the starchy endosperm, was characterized and did not reveal pectin [3], [5]."
Man I don't like reading old articles.

The authors go through a whole litany of factors that make it difficult to extract and purify pectin from hops. In order to extract any tannins they needed to use a solution of acetone (not used in brewing, obviously). They further explain that pectin forms insoluble complexes with calcium (which serves to remove it from wort).
Then at the end of the article they conclude that their samples are impure and they did not successfully validate their method as reliable for quantitatively measuring pectin content in hops.

So, definitely neither one of these articles conclude that pectin makes its way into wort. It seems to me that they support the idea that it doesn't, although obviously not conclusively.

Thanks for the articles, interesting stuff!
 

Gnomebrewer

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Here are another two articles about pectin in barley
https://www.sciencedirect.com/science/article/pii/S0144861718305952
https://www.frontiersin.org/articles/10.3389/fpls.2017.01872/full
Also worth noting is that in this article
https://www.tsi.com/getmedia/15881c...ectroscopy_App_Note_RAMAN-022_US-web?ext=.pdf
Single malt scotch whiskey is found to have a typical methanol content of 0.2 to 0.3%, with levels above that considered contaminated. The methanol in scotch whiskey must be produced during fermentation of the barley wort.
 

doug293cz

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Here are another two articles about pectin in barley
https://www.sciencedirect.com/science/article/pii/S0144861718305952
https://www.frontiersin.org/articles/10.3389/fpls.2017.01872/full
Also worth noting is that in this article
https://www.tsi.com/getmedia/15881c...ectroscopy_App_Note_RAMAN-022_US-web?ext=.pdf
Single malt scotch whiskey is found to have a typical methanol content of 0.2 to 0.3%, with levels above that considered contaminated. The methanol in scotch whiskey must be produced during fermentation of the barley wort.
Methanol can come from charred wood. Think barrel aging, charcoal filtering, etc.

Brew on :mug:
 

Vale71

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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.
No it doesn't. All it does as far as proving a link between alcoholic fermentation and methanol production is to make inferences such as "S. Cerevisiae could be involved in the production of methanol" or "In spontaneous fermentation other naturally occurring bacteria might be responsible for methanol production in spontaneously fermented beverages" and so on and so forth. As of today there is zero proof that Saccharomyces could in any way be involved in the production of methanol. There is lots of speculation asbout that but without proof speculation is just worthless. As somebody else already pointed out there is also zero conclusive proof that the ingredients of beer contain pectin or even if they do that it could be in any way carried over to wort.

So to sum it up there is no proof that malt wort has any measurable pectin content and even if that were the case then there is no proof that any microorganism involved in fermentation is in any way capable of producing any amount of methanol from said pectin. If we apply Occam's razor then we have to conclude that any methanol that might be detected in beer must be exogenous as this is the simplest possible explanation.
 

Vale71

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How is methanol produced in fermentations with pectin?
It simply isn't. Methanol is a naturally occurring constituent of pectin-rich fruits and vegetables, even of common tomatoes as you can see in this study. If fermented and possibly distilled beverages are produced from such fruits then some amount of methanol will inevitably be carried over to the beverage but that does not imply any direct link with the fermentation process.
 

Gnomebrewer

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Methanol can come from charred wood. Think barrel aging, charcoal filtering, etc.

Brew on :mug:
Do you have a reference for that? I can't see how that can happen. Sure, fermentations with wood present produces some methanol, but there's no fermentation involved with whiskey in an oak barrel. The best information I can find (although admittedly not 100% conclusive) still says the methanol is from pectins in the ferment.
 
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