Double action (was) Re: temp misreradings
- Hi Harry.
Sorry, but I don't agree with you. May be it's only matter of
Let me try to explain better my ideas.
In my opinion, if you have a not insulated column you will see this
phenomena (of course I'm talking NOT in a transient but regimated
phase): at the bottom of the column you have a temperature T1 and on
the top you have T2, that is < T1 because there are some heat losses.
At temperature T2 you have only the fractions that can stay as
vapour, that means the lighter components: the heavier components
are already condensated because T2 is less than the condensation
temperature of those ones.
Talking not in terms of temperature but energy (heat): you have at
the bottom of column the 100% of energy: along the column you lose
some -let's imagine - 50% and so, to respect the balance only the
quantity of lighter components that can stay as vapour with that
quantity of energy are present on the top of column.
Let's imagine the phenomena: on the bottom of the column is a mix of
elements that can stay as vapour because the temperature is = or >
than the evaporating temperture of those components.
Climbing along the column the walls are less hot than before, and so
some heavier elements will start to condense. This happen because
the temperature in that point is lower than the condensing
temperature of those elements.
The vapours, such in this way, become more "pure" because lost the
heavier components, or not?
On the top of the column will stay (theoretically speaking) only the
components that have their condensing temperature lower that
temperature existing on the top of the column in that moment.
The condensed liquid, flowing down along the column wall, will meet
hotter zones of wall because hotter climbing vapours, and so for
some elements the evaporating temperature will be reached causing a
This process is less efficient than in a pakaged column, but
something happen. And something is better than nothing.
If you insulate the column, the top temperature is higher than
before, the quantity of energy on the top of the column is higher
too, and so a bigger volume of vapours can stay there. The bigger
quantity is due to the presence of heavier components because the
temperature is higher and so can stay on the top also the elements
that have a superior condensing temperature.
So your column give a heavier spirit than before and this I was
meaning with my post.
How about it?
ciao a tutti
p.s. In your post, Harry, you wrote " ... So the vapours going up
will still contain lots of impurities. So you get more impurities
in the product. " . What do you mean by "impurities"? If you
mean "heavier components" you will get more in an insulated column
because the lower column gradient of temperature help to keep those
What is the meaning of "HTH" immediately before the slainte?
--- In Distillers@yahoogroups.com, "Harry" <gnikomson2000@...> wrote:
> No, you get the exact opposite. If you lose heat through the
> walls, the column cools and the liquids cool and then 'dump'. You
> lose the distilling (separating) action. So your column acts more
> like a potstill. Vapours going up are not condensed and reboiled
> efficiently because there's not enough descending liquid to
> with. This liquid is needed to exchange the latent heat of
> vapourization. That's how vapours condense, by giving up heat to
> the descending liquid. That's how the descending liquid reboils,
> getting heat from the rising vapours. It's a double-action two-
> thing, all the way up the column. Each exchange zone is a
> theoretical plate. But in potstill action it's mostly just one-
> vapours (and impurities) going up.
> So the vapours going up will still contain lots of impurities. So
> you get more impurities in the product. More impurities means
> heavier spirit which needs more maturing time to convert the
> impurities to other nicer things. That's what 'detuning' a column
> is all about. A bit like a car. Change the mixture so it 'runs
> rough' and makes more smoke. :-)
> regards Harry
- The following Distillers poll is now closed. Here are the
POLL QUESTION: Potstillers
How do you decide when to make a cut in your spirit run ?
CHOICES AND RESULTS
- By Taste, 4 votes, 6.15%
- By Smell, 3 votes, 4.62%
- By Taste & Smell, 28 votes, 43.08%
- By Temprature, 15 votes, 23.08%
- By Alchohol Volume, 15 votes, 23.08%
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