Still & condenser

Joe Gwinn fired this volley in news:090920132133580762% snipped-for-privacy@comcast.net:

It will react. It will form formaldehyde in contact with copper.

Oh... minor missed item here... that happens at 300C.

Lloyd

Just to avoid explosive vapors.

The reason I think you should check the corrosive effects on copper is that methanol has been a problem with copper and brass parts in race cars, where it's used as a fuel.

Ignorant guess: so that the flammable vapors won't escape, and possibly catch fire.

As to fusel oils, not a big deal. Circuit boards won't complain of hang overs and head aches. Might even help clean the boards.

. Christ>> I've seen copper-coil condensers run through a bucket of water that

Well, the OP's question is about distilling methanol. I've never heard of fusel oil being a problem with that, although I have no idea.

We also were talking about stills for making drinking-quality ethanol. Fusel oil is a product of fermentation of some sources of sugar and it can be an issue with that distillation.

OK. Making the still airtight will require care and workmanship, but is certainly doable.

I know that ethanol stills have been made of copper forever. The big issue was that the joints needed to be silver brazed, not soft soldered, so the hooch wouldn't contain too much lead.

There is some methanol in the fermented mash, and this too must be discarded to yield potable hooch. The old rule was to discard the first (fusel oils) and last (methanol) fractions, and keep only the middle fraction.

I don't offhand know how much methanol there is in the third fraction, but it isn't going to be a lot.

When methanol is used as a fuel, what is the problem seen with copper and brass parts? Whatever the problem, it will be worse in a still, because of the higher temperature (82 C, not 300 C).

I did a little googling. The effect on aluminum, magnesium, and zinc is pretty rapid, on brass far slower, and pure copper slower still. This assumes that the methanol contains some water, which is easily absorbed from the atmosphere. The methanol vapor in a still will not contain much water, so the corrosion effects may be greatly reduced.

Joe Gwinn

Well, I think you'll find that most of the pot stills made during Prohibition actually were soft-soldered with lead-tin solder.

As I mentioned, my uncle made those things for sale to the moonshiners in the Jersey Pine Barrens during Prohibition. When I was a teenager he taught me how to sweat-solder pre-tinned parts (that's how I soldered almost the entire hot-water heating system in my house), and he described the process of making a still. I've since seen it described the same way elsewhere.

I could tell you the details but it's lengthy. The short version is that the seams were double-folded and they only sweated the contact point between the *outside* of the outer fold and the body of the still. It required a lot of skill and a lot of heat because of the conductivity of the copper. The area was heated with a plumber's gasoline torch and the sweating was done with massive soldering coppers.

The solder never contacted liquid and no significant amount of vapor. If a moonshiner fell asleep and let his pot run dry, the still was ruined because the solder would melt.

It's interesting stuff. If Prohibition comes back, I've got a sideline. d8-)

Hmmm. I thought that methonol had a lower boiling point than ethanol, and that it was part of the initial discard.

My memory could be failing on this point.

Someone mentioned azeotropes earlier in the thread. That's for people with more knowledge than I have, but be aware that some of the volatile liquids involved, and there are a bunch of them in the fermentation/distiallation process, form azeotropes and can't be separated by this kind of distillation. It makes the whole thing fairly complicated but a home distiller only needs to know a few basics.

All I've ever heard is that it corrodes several different metals in an engine, and that copper and brass were among them.

It's not a big problem in racing because you should drain the fuel system after races are over. But it is a problem if you let it sit there.

It's just something to be aware of. What you said there sounds reasonable. The biggest corrosion problem was with carburetors, and they're usually aluminum/zinc diecast alloys.

I don't know about prohibition days but auto radiators are used sometimes used in the boot-legging business as condensers. I remember a news article about a number of people being poisoned in Georgia as a result. The Wiki even mentions it :-)

Oh, yeah. The moonshine business has gone to hell. In the old days, if you sold a bootlegger poison hooch, you could wind up dead.

It was bad for his business.

But that has always been a danger with illicit booze. Some of it has always been poison, with lead, antifreeze (used in wine to sweeten it

-- it kills), methanol, and other crap.

IIRC -- I think the term was "metyhlated spirits" which is UK-speak for "denatured alcohol". Given that this was what he was using, and he was apparently using it to clean printed circuit boards of rosin flux after the soldering, I suspect that a bit of lead is in each batch, too.

If it were for drinking -- do you really think that distillation would recover enough of the used product to be worth the trouble? :-)

Right -- different application of the technology.

Enjoy, DoN.

I understand that adding chicken manure to the mash as a yeast nutrient was also done. the yeast works faster and time is money, as they say :-)

Yes. With better technology - TIG the seams, so no problem if the seams overheat.

Mine too. Now that you mention it, the rule was methanol first, then ethanol, then fusel oils. so one kept the middle. This was the "secret of distillation" discovered by Arab alchemists. The word "alcohol" is of Arabic origin.

The most important azeotrope here is that of water and ethanol, at 95% ethanol and 5% water. This is the highest proof one can get by ordinary distillation.

Yes. That was the implication of much of what I read.

Yes. I think that the bottom line is that a copper still will work just fine with denatured alcohol. Nor will there be any fusel oils.

I'm guessing that denatured alcohol is or is close to the azeotrope of methanol and ethanol; otherwise, it would be too easy to re-nature the ethanol.

Joe Gwinn

Coined, no doubt, by Sheik Yerbouti. Then the Muslims outlawed it when they learned how much fun it could be. d8-)