This does help me think things through a little clearer. Thanks to
you and Tom the Pastor for you advice. If anyone else would like to
relate details of their experiences an adventures in this area, I
would welcome their e-mails directly.
-- In new_distillers@y..., "Kev" <hurne@y...> wrote:
> > I have a couple of questions regarding construction of a reflux
> > column. I've been reading the earlier posts in the group and
> > seems to be some confusing information.
> Everyone's still design is different, so the needs of the column
> different. The basic idea of having a reflux column is to increase
> the number of times your alcohol is distilled. As you say, a reflux
> still is equivalent to putting the stuff through a pot still a
> of times. The trick is to increase this number as much as you can
> get close to the magic 98.something %.
> > One opinion holds that the cooling water supply to the condenser
> > should pass through the column, but another is that there should
> > no additional cooling within the column.
> Cooling water does two jobs in a still. Sometimes these jobs are
> combined, sometimes they are separated. 1) it condenses the vapour
> the condenser head so that you can collect it in liquid form. 2) it
> can be used at the top of the column to increase the reflux ratio
> i.e. returning more product back down the column for re-
> > Yet another says to cool at
> >the top, while others cool about half way up.
> Do it at the top, definitely at the top! The only time it's
> worthwhile doing it lower down is if your heat input is too strong
> for the diameter of column you've got and you need to stop your
> column getting flooded. Look at Tony's website for details of
> column / heating combination recommendations.
> > There are also comments
> > from others that talk of insulating the column, which is entirely
> > opposite principle.
> Yeah, I thought that as well! The idea, as Tom the Pastor says, is
> make sure you're the one in control of the cooling, not the
> > One of the websites claims that in a reflux tower every six
> > equivalent to one pass through a conventional pot still, so by
> > extension, a three feet tower would equate to six passes through
> > pot still. If this is the case, then I can't see the purpose of
> > further cooling within the tower. Would any or all like to
> > this to help clear my thoughts?
> Tony's site (www.geocities.com/kiwi_distiller) also has details as
> how many pot-runs you get per length of column. It also depends on
> the diameter, type of packing, heat, etc., etc., etc., but the
> principle is the same more is better. Having said that, you do
> reach a point where more makes no difference. A 10 meter column
> going to be worth the hassle of finding somewhere big enough to run
> the damn thing, for instance :-)
> > On an allied topic, the packing used in the reflux tower varies
> > Raschig rings to stainless steel scourers to marbles etc. I had
> > initially leaned towards using marbles because of their
> > and ease of cleaning, but now I'm not so sure. The plans that
> > looked at which use the scourers seem to indicate about twelve in
> > column. So if the column is three feet, then that's four to the
> > which even considering the surface area of the packing, still
> > to allow quite a bit of volumetric flow-through. If I used
> > then the packing would be much denser, so what would the overall
> > effect be?
> Again, as Tom said it's the surface area you're trying to increase
> here. This gives the vapour something to condense on and flow back
> down the column for re-distillation. There's more techie stuff to
> than this, but this is the basic idea. Scrubbers give you the best
> surface area and therefore more pot-still equivalents for the same
> length of column packed with anything else.
> As to how many to put in per foot, that depends on the size of your
> scrubbers! I've seen 18 per metre mentioned, but the ones I got
> of filled the column up after just 4. Pack as many in as you can,
> make sure you can still breathe through the packed column
> otherwise the vapour won't be able to pass through it any easier
> your breath and you'll have great refluxing, but zero stuff coming
> out to collect! Watch out when you're packing them in there, too,
> I cut my hands to ribbons on mine.
> OK, that's refluxing in a nutshell, then we move on to
> This is basically the same thing, but very controlled. You have ALL
> the distillate at the top of the column flowing back down the
> for re-distillation and eventually you get the various sub
> of the brew stacked like planes over Heathrow airport, with the one
> with the lowest boiling point (methanol) at the top. Once the
> has settled out (several hours, possibly) you start to draw off
> amounts of the distillate to collect. Obviously, you dump the
> methanol, and you can tell when this has finished coming off by the
> thermometer at the top of your column. Check Tony's site again for
> the exact temps, but from memory the good stuff is at 78.something
> degrees C.
> I hope this helps.