Loading ...
Sorry, an error occurred while loading the content.

CM VS VM

Expand Messages
  • orientalcreek
    Greetings to the group and thanks for the all the very valuable information I have gleaned from the site over the last year. I thought I would share some of my
    Message 1 of 2 , May 14, 2010
    • 0 Attachment
      Greetings to the group and thanks for the all the very valuable information I have gleaned from the site over the last year.

      I thought I would share some of my experiences and perhaps learn something from the more experienced practitioners of this most enjoyable hobby.

      My first still was a CM design, 2" copper column, apprx 36" copper packing and 15 Gal SS Keg, Propane heat source. The reflux condenser is a cold finger inserted in the top of the column and the product condenser is a Leibig apprx 30" in length. The condensers are individually adjustable. Right out of the box the still produced 94+ percent product, crystal clear. True to the wisdom of the group, it was tricky to keep stable. However, once I converted the boiler to electric heat, except for being a bit "fiddly" to get everything adjusted at startup it was as stable as a rock and would produce distillate from beginning at about 94% at the start of the run that would gradually decline until about 90% at which time the rate of decline would rapidly increase. The distillate has always been characteristically crystal clear and the mids have always been very "clean" with respect to odors or off flavors. I have never needed to use charcoal or other means to remove objectionable tastes from the distillate.

      But, I have read about the wonders of VM and the holy grail of 95% distillate and lusted for the ultimate still, an easily controlled VM that would put out 95% product of very high quality.

      I built a 2"VM column with apprx 42" of copper packing and a 1" takeoff with ball valve & 30" Leibig condenser. The VM reflux condenser is a double wound copper coil located above the takeoff point. I have used two different styles of 2" Copper pipe to house the VM condenser. One is simply a straight tube, and the other is a tube in which the end toward the takeoff port has fingers bent inwards to direct the reflux toward the center of the column. I cleaned everything thoroughly, put the system together and with great expectations plugged the system in. The wash was apprx 12% alcohol barley, corn, sugar that I have used many times.

      The results were mixed. The distillate was apprx 95%, but it had a cloudy haze that I have not seen before. No amount of fiddling with high heat, low heat, valve positions and condenser flow got rid of the haze. Otherwise it was predictable and easy to set reflux rate with the ball valve. I tried this wash with my old still; the results... 93+% & crystal clear.

      So, I reconfigured the VM still into a CM configuration by putting a reflux condenser below the takeoff point, capped the column just above the takeoff point and left the vapor valve at full open. I brought the column up to operating temp and made it reflux for about 45 min and gradually reduced reflux condenser flow to allow distillate to reach the Leibig. I collected foreshots & heads at 95% and clear as crystal. Then proceeded to collect mids until the distillate dropped to about 92.5%. The smell was clean and distillate was crystal clear. It was a little fiddly to get adjusted, but was stable as rock once setup. The heat input in all cases was about 2kW.

      The question is why?

      My theory is that the key difference between VM, LM and CM is that VM and LM allow vapor and reflux containing everything that makes it to the top of the column to pass the takeoff port. CM on the other hand refluxes everything except the vapors allowed to enter the Leibig product condensers. I have concluded that the CM reflux condenser performs a last stage of separation of fractions in the vapor stream before the takeoff port and this accounts for the marked improvement in product quality between VM, LM and CM. Perhaps this is why I have never had to do any post distillation carbon filtering on my distillate. Needless to say I no longer lust after VM as before, but am befuddled over my less than good experience with the VM still. I have used two different types of column packing with identical results. The first is the usual copper mesh, and the second is 3/4"diameter copper rings made from #12 copper wire.

      Do the really experienced practitioners of the hobby have any ideas thoughts on my results.
    • ric
      Way too much heat input. I use 2400W to approach a boil then reduce it to 680w to equilibrate and for the run. ric
      Message 2 of 2 , May 15, 2010
      • 0 Attachment
        Way too much heat input.
        I use 2400W to approach a boil then reduce it to 680w to equilibrate and for the run.

        ric


        --- In Distillers@yahoogroups.com, "orientalcreek" <ozenith@...> wrote:
        >
        > Greetings to the group and thanks for the all the very valuable information I have gleaned from the site over the last year.
        >
        > I thought I would share some of my experiences and perhaps learn something from the more experienced practitioners of this most enjoyable hobby.
        >
        > My first still was a CM design, 2" copper column, apprx 36" copper packing and 15 Gal SS Keg, Propane heat source. The reflux condenser is a cold finger inserted in the top of the column and the product condenser is a Leibig apprx 30" in length. The condensers are individually adjustable. Right out of the box the still produced 94+ percent product, crystal clear. True to the wisdom of the group, it was tricky to keep stable. However, once I converted the boiler to electric heat, except for being a bit "fiddly" to get everything adjusted at startup it was as stable as a rock and would produce distillate from beginning at about 94% at the start of the run that would gradually decline until about 90% at which time the rate of decline would rapidly increase. The distillate has always been characteristically crystal clear and the mids have always been very "clean" with respect to odors or off flavors. I have never needed to use charcoal or other means to remove objectionable tastes from the distillate.
        >
        > But, I have read about the wonders of VM and the holy grail of 95% distillate and lusted for the ultimate still, an easily controlled VM that would put out 95% product of very high quality.
        >
        > I built a 2"VM column with apprx 42" of copper packing and a 1" takeoff with ball valve & 30" Leibig condenser. The VM reflux condenser is a double wound copper coil located above the takeoff point. I have used two different styles of 2" Copper pipe to house the VM condenser. One is simply a straight tube, and the other is a tube in which the end toward the takeoff port has fingers bent inwards to direct the reflux toward the center of the column. I cleaned everything thoroughly, put the system together and with great expectations plugged the system in. The wash was apprx 12% alcohol barley, corn, sugar that I have used many times.
        >
        > The results were mixed. The distillate was apprx 95%, but it had a cloudy haze that I have not seen before. No amount of fiddling with high heat, low heat, valve positions and condenser flow got rid of the haze. Otherwise it was predictable and easy to set reflux rate with the ball valve. I tried this wash with my old still; the results... 93+% & crystal clear.
        >
        > So, I reconfigured the VM still into a CM configuration by putting a reflux condenser below the takeoff point, capped the column just above the takeoff point and left the vapor valve at full open. I brought the column up to operating temp and made it reflux for about 45 min and gradually reduced reflux condenser flow to allow distillate to reach the Leibig. I collected foreshots & heads at 95% and clear as crystal. Then proceeded to collect mids until the distillate dropped to about 92.5%. The smell was clean and distillate was crystal clear. It was a little fiddly to get adjusted, but was stable as rock once setup. The heat input in all cases was about 2kW.
        >
        > The question is why?
        >
        > My theory is that the key difference between VM, LM and CM is that VM and LM allow vapor and reflux containing everything that makes it to the top of the column to pass the takeoff port. CM on the other hand refluxes everything except the vapors allowed to enter the Leibig product condensers. I have concluded that the CM reflux condenser performs a last stage of separation of fractions in the vapor stream before the takeoff port and this accounts for the marked improvement in product quality between VM, LM and CM. Perhaps this is why I have never had to do any post distillation carbon filtering on my distillate. Needless to say I no longer lust after VM as before, but am befuddled over my less than good experience with the VM still. I have used two different types of column packing with identical results. The first is the usual copper mesh, and the second is 3/4"diameter copper rings made from #12 copper wire.
        >
        > Do the really experienced practitioners of the hobby have any ideas thoughts on my results.
        >
      Your message has been successfully submitted and would be delivered to recipients shortly.