"Fredxxx" wrote in message
news
On 03/10/2017 05:14, Rod Speed wrote:


"Fredxxx" wrote in message
news
On 03/10/2017 01:21, Rod Speed wrote:


"NY" wrote in message
o.uk...
"Ade" wrote in message
news On 01/10/2017 23:09, jim wrote:
Tim Streater Wrote in message:
In article , Jethro_uk
wrote:

Annoyingly, it's very hard to get all the water out of
ethanol/water
due
to the boiling point of the mixture being slightly lower than the
boiling
point of water (96C IIRC). Azoetrope IIRC again ....

Isn't the boiling point if ethanol even lower?


:-)


Ethanol bp is 78c which is why it is so easy to seperate from
Methanol at 64c when brewing.

And the boiling point of ethanol/water mixture at its 95/5% mixture is
fractionally *lower* than for pure ethanol (78.2 for the mixture, 78.4
for pure ethanol) so you can never get pure ethanol by simple
distillation. Apparently the way round this is add an "entrainer" such
as benzene or cyclohexane which preferentially binds with the water.
This triple mixture boils at 62 degrees and the water/benzene boils
off, leaving (in theory) pure ethanol as a residue.

Alternatively you add calcium oxide which binds chemically with the
water and the resulting calcium hydroxide can be filtered off,
allowing the filtrate to be re-distilled to extract pure ethanol.


I'm not sure whether ethanol/water forms a similar azeotrope for
freezing, and whether you can separate them by freezing, since ethanol
and water (separately) freeze at different temperatures.

No you can't get rid of the last of the water that way. Thats why
benzene is used to produce absolute alcohol, no water at all.

I remember an ice-cream van owner where we bought an ice cream telling
my dad about separating alcohol from water by freezing in a
deep-freeze,

Yeah, but distillation works better and is easier to organise too.

It may be more effective, but not as easy as putting a pot of alcohol
water mixture in a freezer and decanting off a strong ethanol liquor.

When you have the still, it is in fact much easier. Just tip what has
been
fermented into the still, discard the first run from the still, watch the
digital thermometer to see when the still temp starts rising again when
the ethanol has stopped coming off, turn off the still. Even you should
be able to manage that.

Yes, I have distilled in the past. Comparing the two it's much easier to
put a container in a freezer.

The problem isnt putting it in the freezer, even you can manage that.

The problem is with how much fits in the freezer and keeping
on doing that with the entire batch you ferment, stupid.

Stills are notoriously dangerous.

Ony for terminal ****wits like you.