Robert, I'm not sure where you heard the bit about boiling point of a
mixture "freezing" at the boiling point of each volatile liquid in the
mixture (I'm assuming until that specific liquids is all boiled off?),
but that's not how boiling points work, and operating on that assumption
will just drive you crazy.
As determined by Roualt's
law, the boiling point of a mixture of
volatile liquids is determined solely by the mass and molecular weight
of each (and all) compound, and the atmospheric pressure, and the
composition of the vapor boiled off is also determined by those same
factors. As boiling progresses, the composition of the boiling wash
changes gradually, so the boiling point also changes gradually.
Contrary to some practices, I am an experienced potstiller
that does use
a head thermometer, although I'd never use it to make cuts on an unknown
wash, because different washes benefit from cuts at different
temperatures. For the sake of general information, I've graphed a lot of
still run head temperatures with time, and once the wash boils, the
curve is always as smooth as I expect it to be.
The best model to understand how the curve is continuous is to look at a
graph of boiling points and percentages for a simple binary mixture of
ethanol and water. Yes, it's a first approximation of wash behavior, but
it's a pretty darned good first approximation.
The blue curve represents the percentage of ethanol in the liquid over
the range of boiling points, and the red curve represents the percentage
of ethanol in the vapor that boiled off at that boiling point.
From that curve, if you have a 10% wash, it will boil at ~93C (199F) and
as the percent of ethanol in the wash approaches zero, the temperature
of the wash will approach 100C (212 F). As long as the mixture is
boiling, you have absolutely no control over its temperature; turning up
the power only makes vapor faster.
Just as a very very general idea, and because I'm on the road and don't
have access to my files (but I do have some graphs in my book), for the
grocery store wine I distilled in my coffeepot still, foreshots
heads were up to ~91C (196F) and hearts were 91-94C (196-201F).
Everything after that was tails, which I still collect and distill again
with other junk alcohol.
I know a few people who have made oat whiskey. I'm not sure why more
Zymurgy Bob, a simple potstiller
--- In mailto:new_distillers%40yahoogroups.com, RLB wrote:
> I am a newbie to distillation, 6 total stripping runs, and not not one
finish run to date. My family were not moonshiners, and with AFT and
TTB getting a woody every time they think someone is Moonshining I will
pass on trying to become a still hand. This is all a new learning
process for me know matter how much I read.
> I use a thermometer to see where my boiling points are in my new pot
still. All of my web site reading states that temps will freeze every
time it hits a new alcohol boiling point no matter how high you set your
heat. For me Ethanol starts to boil from 191 to 193, so I sniff the
end of my condenser to define all of the different cuts in a stripping
run. For my stripping runs, my fore-shots will curl your toes, heads
has an unpleasant strong smell, hearts has a strong smell with a sweet
bouquet, and tails smell like a wet dirty sock. What I mean by strong
smell: Take a sniff of +50% abv alcohol vapor. Who needs to ever drink
when those vapors will make you as drunk without ever having a hangover.
Yes, it might be true that most experienced people do not use a
thermometer in a pot still, but I find knowing where the different
boiling points are as being very helpful in my learning process. So
far, all of my experience involves sugar washes,
> and my first grain experiment will most likely be with oatmeal. I
find it interesting that there is so little mention of oats. Oats have
30 to 33 percent sugar, but very little spirits come from oats
> From: bleu jeanzz
> To: "mailto:new_distillers%40yahoogroups.com"
> Sent: Thursday, January 31, 2013 11:39 PM
> Subject: Re: [new_distillers] Re: Re-distillation ??
> Robert, you run a pot still with out a thermometer. They are
worthless in a pot still. Make your cuts by smell, taste and feel. I
don't know anyone who makes good stuff who uses a thermometer for
anything other than entertainment value on a pot still.