Problems with fractioning still

[Uncle Jesse]

from the old message boards:

Muf
(stranger)
11/03/01 01:40 PM
subject: Problems with fractioning still

Hi all,
I hope this is the right forum.
I have made my own fractioning still and it seems to work fine. I am using windscreen glass as the packing and the packing height is about 1200mm. The problem I have is that the result smells of metho. I remove the first 200mls from 20l and that smells of pure metho. After that finishes the temp rises to about 78degrees and runs at this for about 6 hours where the rest comes off. It still has a slight metho smell and the local homebrew shop is telling me that it should be odorless and tastless. I let the still settle for about two hours before taking any alcohol and if I run it through again it shows no changes. The alcohol it get reads 95+ on the hydrometer at room temp.

regards

desprate....(Muf)l


Anonymous
(Unregistered)
11/09/01 11:38 AM
Re: Problems with fractioning still [re: Muf]

my guess is that the column hasn't reached equilibrium.
Let the column sit under full reflux for a while.
The foreshots then concentrate in the upper part of the
column and then you slowly draw off the concentrated foreshots, eventually reaching the ethanol fraction. If you draw off too much, you ruin the seperation of the different vapours. Maybe start with collecting a drop per second after establishing equilibrium- of course the proper rate depends on column diameter, packing, heat input, etc.
Another suggestion is to replace that glass packing with
metal scouring pads as per on Tony's site.
(under theory and calculations)

Good luck


Muf
(stranger)
11/10/01 06:46 PM
Re: Problems with fractioning still [re: Anonymous]

Thanks for the advise, I used to have scouring pads in the still but it didnt behave very well, the glass gives a very steady stepped run. I have a copper condenser and when a run is finished it has a 'rust' on it that will come off on your hands. Do you think this may be causing some problems.

regards

Muf


Tony
(stranger)
02/18/02 11:15 PM
Re: Problems with fractioning still [re: Muf]

Muf,

It sounds as though you're doing everything exactly right. Have you had any other 95% ethanol to compare the smell of ? Its not exactly tasteless - it does have a somewhat alcohol smell to it.

How slowly are you taking off the foreshots (the first 200 mL) - as a slow drip, or faster ? It may pay to slow this down, so that they concentrate up more, and don't linger around into the stuff following the 200 mL.

Tony


Muf
(stranger)
02/23/02 03:11 PM
Re: Problems with fractioning still [re: Tony]

Hi Tony,
I think I may have been taking it off a bit quick, I am running the alcohol through the stil 2 or 3 times now as each time I run it through I still get a small amount of evil smelling stuff at the start. Each time I dilute the alcohol to 50% before running through.

regards

Muf


Tony
(stranger)
02/23/02 09:01 PM
Re: Problems with fractioning still [re: Muf]

Theres no need to dilute to 50% each time if you don't want to. Just make sure that theres enough water present so that any internal heating elements will still be covered at the end of the run. By not diluting, you'l get a higher purity product resulting.

Tony


PieterPost
(Unregistered)
03/27/02 04:28 AM
Re: Problems with fractioning still [re: Muf]

hmmm, did you also check your brew ? I once had an infection and that was the cause of having 10 % of methanol in my distillation product. This is difficult to remove with home equipment. There should be only very little methanol when starting your destillation process. You can check this by looking under the microscoop. If you don't have a microscoop try asking around, people who have studied biology are bound to have one. It is also possible to go to a biology department somewhere, they wil be glad to help you even more so if you promise them a bottle when you can do this regularly.
Hope this helps


unclejesse
(stranger)
03/28/02 11:42 AM
Re: Problems with fractioning still [re: PieterPost]

how can one distinguish methanol via microscope? what does methanol look like, what does ethanol look like? is it obvious if i compare some whisky to some isopropyl?


PieterPost
(stranger)
03/30/02 01:06 AM
Re: Problems with fractioning still [re: unclejesse]

UncleJesse you are right, one cannot distinguish methanol from ethanol under a (ordinary) microscoop. I think i was not clear in what I meant. One should look for bacteria for they produce methanol. Yeast doesn't produce methanol, so under the microscoop one should look for rod-shaped organisms. Yeast should appear oval with or without buds on them. When yeast divides it does this by budding but that's a nother story.
So if you find rod shaped organisms in your brew I would throw it away as methanol cannot efficiently be separated from methanol with home equipment. (by the way: the industry uses distillation coloms of many meter high to separate these liquids from each other.)
Hope I've cleared up my first story