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RE: [new_distillers] First time still almost ready.......

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  • Tony & Elle Ackland
    Ron, ... It needs to be sealed enough not to leak too much steam/vapour. Fuzzy precisness - eg a wee leak is probably ok (mine does), but a major puffing
    Message 1 of 3 , Sep 29, 2001
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      Ron,


      > 2. Either way the lid just sits on the top of the tub, I was planning
      > to clamp the lid on. Do I need a gas tight seal? If so would Silicon
      > mastic for a fish tank do? was planning to extrude a bead onto the
      > lid and put some vaseline on the tub to stop it sticking together. Or
      > perhaps some silicon tube used as a seal would do?

      It needs to be sealed enough not to leak too much steam/vapour. Fuzzy
      precisness - eg a wee leak is probably ok (mine does), but a major puffing
      point is a problem. The silastic & vasoline trick works well.

      > 4. I have cleaned the copper internally with vinegar and it went
      > green and then I flushed it with water, is this enough?

      Thats all I did


      > 5. I have seen in many designs the requirement to put a piece of
      > brass mesh across the entrance to the reflux tube, but the scrubbers
      > don't look like they will come out unless you pull them, is a screen
      > necessary? (PS. I boiled the SS first before inserting them in the
      > tube)

      The screen is really only for designs with loose packing like raschig rings
      or marbles. The scrubbers should be able to hold themselves up.

      >
      > 6. I have put 14 scrubbers in the tube and can easily blow through
      > it. I read somewhere that for 1.2m I should use 17, but this would
      > compress them quite a lot more, any suggestions?

      Too many can give problems. Their tightness is a hard thing to describe.
      Like don't compress them more than what they'd look like when just sitting
      on the bench. The main trick is to fill as much of the column height as
      possible.

      >
      > 7. Where the Reflux tube joins the top coil condensor I have used a
      > 42mm straight copper connector, soldered to the top piece, but push
      > fit to the bottom with 50mm of overlap. I was planning to leave this
      > unsoldered to make it easier to clean, is this OK or should I go for
      > a soldered connection.

      Theres very little pressure there, so a push joint is fine. You might just
      want to use a little teflon tape / plumbers tape to help get it sealed

      >
      > 8. I deliberately made the Nixon-Stone condensor very long to be
      > absolutely sure that no vapour would escape. The idea was to estimate
      > the reflux ratio by running the still with boiling water (should I do
      > this with beer vapourising?) and when boiling send enough water flow
      > through the Nixon-Stone condensor, with the coil condensor shut off,
      > for the Nixon-Stone to condense all the vapour to liquid. Then I
      > would measure the flow per second. After that I was planning to run
      > the internal coil condensor at the top of the Reflux column until the
      > flow of condensate from the Nixon Stone reduced by 85%, giving me a
      > 5:1 reflux ratio. Is the correct way to estimate the reflux ratio?

      On a per mL basis, it takes a lot more energy to evaporate water than it
      does alcohol. Definately use the water only run to get a starting idea,
      but then repeat what you've described, once you've got some alcohol in the
      system. Treat the first run as a real experiment - try different reflux
      ratios - see what temperatures / purity you get, how fast is flat out ?,
      etc. Learn the sounds & smells & hot bits to touch, etc. If you mess up
      the distillate with some low grade material, then just redistill it all a
      second time, and collect it for real then.

      Rather than target a specific reflux ratio (5:1), learn whats best for your
      still. Being so tall, you might be able to get away with something less
      (eg collect faster). For shorter columns, they may need more. Work all
      this out during your experimental run - for a particular collection rate
      (and hence reflux ratio), see what vapour temperature you get at the top of
      the column, and hence its purity there (see attached graph).

      >
      > 9. Lastly, I was planning to ferment 100 litres of beer, if I measure
      > the specific gravity by volume, and take 85% of this figure, is that
      > a reasonable assumption for the amount of ethyl alcohol I can
      > distil. (This question is not about trying to get the most alcohol I
      > can get, but more an estimate of how long it will take to get to the
      > point where "Tails" are being produced?)

      I reckon more like 95% is attainable. The tails really depend on how good
      the still is. A tall column should give you a really stable run at high
      purity, right up to the end. After the collection rate has slowed right
      down (eg you're needing a silly high reflux ratio to keep the purity),
      change to collect the tails. Off 25L, I'd probably get less than 300 mL of
      low purity tails up to 96C. So you're maybe looking at 1L ? Might be
      less, as you should be able to concentrate them up better. The trick with
      all of this is in watching the vapour temperature, and keeping on top of
      it via the reflux ratio.

      >
      > 10. Also, based on 9. above, is there a way to estimate the amount
      > of "heads" to discard?

      Depends on your starting materials, how happy the yeast was, and if you
      avoided high temperatures during fermentation. A happy sugar wash with
      sufficient nutrients should give very little (10-20mL ?) of heads, however
      a badly infected grain mash will give you 1-2L (don't ask how i know
      this..). Likewise, if you let the column equilibriat e under total reflux
      say for 15-20 minutes at the start, and then start slowly collecting the
      heads at a rate of 1 drip per second, you'll get them off really
      concentrated (and really easy to spot by nose !). Maybe 50-100 mL off 100L
      of beer ? Again, the signal that they're over is when the temperature
      lifts out of the high 60's low 70's, and moves up to around 78.2C. Use
      your nose - the first part of the ethanol will still have some
      smell/flavour with it - its for you to decide which you'll recycle, which
      you'll keep for heavy flavored spirits, and when to take the really clean
      and neutral "heart" of the middle run for your best gin & vodka.

      >
      > Any other suggestions would be gratefully received?
      >
      > After I have run it I will post my results if anyone is interested
      > and or a photo of the working still.

      Yes please !


      Tony
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