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Re: Bokakob as pot still

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  • rye_junkie1
    ... In an LM set up I like the Idea of the Pool it puts you in control of the Reflux ratio. The way your rig is set up you have no way of knowing what the
    Message 1 of 10 , Mar 4, 2009
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      --- In new_distillers@yahoogroups.com, "Andy" <fit_dude42@...> wrote:
      >
      > Mason,
      >
      > No problem, no frustration noticed.
      >
      > Many thanks for the response. You're quite right in that my still
      > does not religiously follow the plans from Bokakob and that most of
      > my condensate falls straight back down the column as reflux and only
      > a small splash gets collected. However, that small splash can be up
      > to 1l per hour at 90+%.
      >
      > In the original design, all the condensate falls into a 'pool' on
      > the take-off plate and then overflows back down the column as
      > reflux. Is it critical that there's a 'pool' of distillate at the
      > take-off point?
      > I'm assuming (please correct me if i'm wrong, i need to learn) that
      > whatever vapour has emerged at the top of the packing (assuming
      > appropriate heat input) is as pure as its going to get i.e. all the
      > separating/stripping has taken place in the packing. If so then
      > the 'pool' of distillate is not strictly necessary and is just a
      > method of controlling the output, and my still should produce the
      > same effect???
      >
      > I've gone past the 'this works, use it' stage and am into the 'this
      > works - why?' stage.
      >
      > Th reason i ask about flow rate is because i get up to 1l per hour
      > at 90+% on reflux - what would this go up to as a pot still? I'm
      > assuming again that in the middle of the run you're collecting
      > everything a fast as possible. Have i got this right?
      >
      > Many thanks again.
      >
      > Andy


      In an LM set up I like the Idea of the "Pool" it puts you in control of the Reflux ratio. The way your rig is set up you have no way of knowing what the "true" maximum output of the rig is for a given heat setting. Being able to determine the RR is very important especially if you plan on using the rig for whiskey. For neutral you want to collect 10%of the condensed vapor and return the other 90% to the packing. Doesnt sound like a issue with your rig. For a Rum or Whiskey however that ratio should be more like collect 50-60% and return the rest down the column(no packing) maybe even 70/30. You have no way of determining this because of the way the rig is made.
      You can always try it and see what you get. You may be very happy with it. Thats all that matters. The machinist in me does not allow for this kind of thought process. I have to know what is happening (to a degree I understand)and be able to control it.
      The reason your rig works as well as it does is because of the Built in reflux ratio. I believe you use 2.5" tube at near 3' in length. Thats going to get you a high level of purity if you run it right.
      How much power are you running to the boiler? From the looks of the pic you would be using Propane? Is your drinking product from a 90+% spirit run "neutral" in taste? I ask because at 1L/hour and what you have told us about your rig you would have to be pouring the BTU/watts to it to get that take off rate. That or things line up better than you may think.
      As for take off rate for a pot still. I use a pot still for pot stillin. 750-1000 watts would set the take off rate. Or when i used propane, about 1l/hour. For the spirit run I like to run it slow.

      Mason
    • Andy
      Mason, you re quite correct in that i can t get any more out of my rig because of the lack of the pool at the take-off point. I m actually taking off
      Message 2 of 10 , Mar 6, 2009
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        Mason, you're quite correct in that i can't get any more out of my rig because of the lack of the 'pool' at the take-off point. I'm actually taking off everything that falls onto the plate where the pool should be, it just happens to be at the right ratio. I think it's more luck than judgement, but it worked so i left it alone.

        I use a 1960's pressurised paraffin (kerosene) stove to heat things up. Based on the heat-up times on my one-time use of a 2.4kw electric hob (it took hours!), i reckon on full pressure this stove must be hitting at least 4kw but it's pretty controllable. When i had the 5L boiler the electric hob was fine (although a bit expensive to run in the U.K.) and it could be on full power (2.4kw) all through the run. When i changed to the 25L boiler, it just couldn't cope. After trying a couple of open-flame methods i settled on the paraffin stove which works great.

        Thank you for answering the question about how much to take off on a pot run. I'd wrongly assumed that nothing went back down the column i.e. everything that went up it got condensed and collected. I've definitely got to alter the design as i can't collect any more than i do at present. It'll be interesting to see what the real flow rate could be.

        The product is pretty good taste-wise. If i want to make 'vodka' i have to carbon filter a couple of times, but if i flavour it i just filter once and drink. After the excellent advice on here i was able to remove the only slight off-taste that came through, but even that wasn't bad when it was flavoured.

        From reading your response regarding the purity (column size), flow-rate, heat input etc, am i right in thinking i could possibly run this rig at a higher take-off rate if the 'pool' were there? At the column height i've got, is there any purity advantage in running a higher reflux ratio? Or does it level off after a certain point and i'm just not collecting enough?

        Many thanks for the response again

        Cheers,

        Andy.

        --- In new_distillers@yahoogroups.com, "rye_junkie1" <rye_junkie@...> wrote:
        >
        > --- In new_distillers@yahoogroups.com, "Andy" <fit_dude42@> wrote:
        > >
        > > Mason,
        > >
        > > No problem, no frustration noticed.
        > >
        > > Many thanks for the response. You're quite right in that my still
        > > does not religiously follow the plans from Bokakob and that most of
        > > my condensate falls straight back down the column as reflux and only
        > > a small splash gets collected. However, that small splash can be up
        > > to 1l per hour at 90+%.
        > >
        > > In the original design, all the condensate falls into a 'pool' on
        > > the take-off plate and then overflows back down the column as
        > > reflux. Is it critical that there's a 'pool' of distillate at the
        > > take-off point?
        > > I'm assuming (please correct me if i'm wrong, i need to learn) that
        > > whatever vapour has emerged at the top of the packing (assuming
        > > appropriate heat input) is as pure as its going to get i.e. all the
        > > separating/stripping has taken place in the packing. If so then
        > > the 'pool' of distillate is not strictly necessary and is just a
        > > method of controlling the output, and my still should produce the
        > > same effect???
        > >
        > > I've gone past the 'this works, use it' stage and am into the 'this
        > > works - why?' stage.
        > >
        > > Th reason i ask about flow rate is because i get up to 1l per hour
        > > at 90+% on reflux - what would this go up to as a pot still? I'm
        > > assuming again that in the middle of the run you're collecting
        > > everything a fast as possible. Have i got this right?
        > >
        > > Many thanks again.
        > >
        > > Andy
        >
        >
        > In an LM set up I like the Idea of the "Pool" it puts you in control of the Reflux ratio. The way your rig is set up you have no way of knowing what the "true" maximum output of the rig is for a given heat setting. Being able to determine the RR is very important especially if you plan on using the rig for whiskey. For neutral you want to collect 10%of the condensed vapor and return the other 90% to the packing. Doesnt sound like a issue with your rig. For a Rum or Whiskey however that ratio should be more like collect 50-60% and return the rest down the column(no packing) maybe even 70/30. You have no way of determining this because of the way the rig is made.
        > You can always try it and see what you get. You may be very happy with it. Thats all that matters. The machinist in me does not allow for this kind of thought process. I have to know what is happening (to a degree I understand)and be able to control it.
        > The reason your rig works as well as it does is because of the Built in reflux ratio. I believe you use 2.5" tube at near 3' in length. Thats going to get you a high level of purity if you run it right.
        > How much power are you running to the boiler? From the looks of the pic you would be using Propane? Is your drinking product from a 90+% spirit run "neutral" in taste? I ask because at 1L/hour and what you have told us about your rig you would have to be pouring the BTU/watts to it to get that take off rate. That or things line up better than you may think.
        > As for take off rate for a pot still. I use a pot still for pot stillin. 750-1000 watts would set the take off rate. Or when i used propane, about 1l/hour. For the spirit run I like to run it slow.
        >
        > Mason
        >
      • rye_junkie1
        ... Harry and Riku gave me some schooling on this back in January. With the info Harry gives here, you should be able to figure out what is optimal (reflux
        Message 3 of 10 , Mar 6, 2009
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          --- In new_distillers@yahoogroups.com, "Andy" <fit_dude42@...> wrote:

          > From reading your response regarding the purity (column size), flow-rate, heat input etc, am i right in thinking i could possibly run this rig at a higher take-off rate if the 'pool' were there? At the column height i've got, is there any purity advantage in running a higher reflux ratio? Or does it level off after a certain point and i'm just not collecting enough?
          >
          > Many thanks for the response again
          >
          > Cheers,
          >
          > Andy.


          Harry and Riku gave me some schooling on this back in January.
          With the info Harry gives here, you should be able to figure out
          what is optimal (reflux wise) for heat input on your rig.
          http://groups.yahoo.com/group/Distillers/message/44183

          I do know that in "The Compleat Distiller", they talk about doing a reflux run with a 2" diameter column at around 750watts and about 1-2 drops/second. So your talking about 500-600ml/hour for azetrope alcohol.

          Mason
        • abbababbaccc
          ... With accurate control of reflux ratio you can get 1 liter / hour using that power and 2 column. With some trick and treats you can up the power and get
          Message 4 of 10 , Mar 6, 2009
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            --- In new_distillers@yahoogroups.com, "rye_junkie1" <rye_junkie@...> wrote:
            >
            > --- In new_distillers@yahoogroups.com, "Andy" <fit_dude42@> wrote:
            >
            > > From reading your response regarding the purity (column size), flow-rate, heat input etc, am i right in thinking i could possibly run this rig at a higher take-off rate if the 'pool' were there? At the column height i've got, is there any purity advantage in running a higher reflux ratio? Or does it level off after a certain point and i'm just not collecting enough?
            > >
            > > Many thanks for the response again
            > >
            > > Cheers,
            > >
            > > Andy.
            >
            >
            > Harry and Riku gave me some schooling on this back in January.
            > With the info Harry gives here, you should be able to figure out
            > what is optimal (reflux wise) for heat input on your rig.
            > http://groups.yahoo.com/group/Distillers/message/44183
            >
            > I do know that in "The Compleat Distiller", they talk about doing a reflux run with a 2" diameter column at around 750watts and about 1-2 drops/second. So your talking about 500-600ml/hour for azetrope alcohol.
            >
            > Mason
            >

            With accurate control of reflux ratio you can get 1 liter / hour using that power and 2" column. With some trick and treats you can up the power and get 1.6 liters/hour. The values given in TCD are a good baseline and once you master it you can start towards faster rate.

            Slainte, Riku
          • Andy
            This is what i want - maths that prove i m doing it wrong! ;-) Thanks for the link, i d not seen these calulations before. Really useful. According to the
            Message 5 of 10 , Mar 7, 2009
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              This is what i want - maths that prove i'm doing it wrong! ;-)

              Thanks for the link, i'd not seen these calulations before. Really useful.
              According to the calc's, my column has a packing capacity of 137cu.in. which is o.k. At 2kw input the vapour speed is 18 inches/s which is within the advised limits.
              What i now suspect is happening is that i'm overpowering the column, which is reducing the effectiveness of the packing. If i modify the take-off to get that 'pool' i'll probably find that the take-off rate is too high and i should need to reduce my heat input. This should make the packing more effective which should improve the product for less heat cost.

              Fantastic!

              Cheers,

              Andy.


              --- In new_distillers@yahoogroups.com, "rye_junkie1" <rye_junkie@...> wrote:
              >
              > --- In new_distillers@yahoogroups.com, "Andy" <fit_dude42@> wrote:
              >
              > > From reading your response regarding the purity (column size), flow-rate, heat input etc, am i right in thinking i could possibly run this rig at a higher take-off rate if the 'pool' were there? At the column height i've got, is there any purity advantage in running a higher reflux ratio? Or does it level off after a certain point and i'm just not collecting enough?
              > >
              > > Many thanks for the response again
              > >
              > > Cheers,
              > >
              > > Andy.
              >
              >
              > Harry and Riku gave me some schooling on this back in January.
              > With the info Harry gives here, you should be able to figure out
              > what is optimal (reflux wise) for heat input on your rig.
              > http://groups.yahoo.com/group/Distillers/message/44183
              >
              > I do know that in "The Compleat Distiller", they talk about doing a reflux run with a 2" diameter column at around 750watts and about 1-2 drops/second. So your talking about 500-600ml/hour for azetrope alcohol.
              >
              > Mason
              >
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