GC Analysis of Neutral

edited April 2016 in General

I got the guys at work to test my neutral produced from Ace's Foolproof Neutral recipe on a 4" 7 plate ProCap still. Stripped then spirit run on 7 plates no packed section. One of the first goals I have set myself in distilling from home is to match the commercial specs for neutral ethanol.

Results are in:

  • Strength 93% (fail)
  • Methanol 13ppm (smashed the spec of <40ppm)
  • Acetal 2ppm (spec <10ppm)
  • Acetaldehyde 2ppm (spec <10ppm)

I just need to solve my packed section flooding problem to get more theoretical plates and I will try again.

However I am chalking this up as a win!


  • I wonder how my turbo through a packed section would compare?
    What sort of reflux ratio were you running at?

  • That was off take at 2 litres per hour so pretty slow compared to others.

    Feel free to send me a small sample in the mail and I can get it tested. Only need about 50ml.

  • I'd like to do that. Could be very interesting.
    I'd want to do a run under known conditions for it though so we know exactly what we've got.

  • when you are ready just PM me and I will send you my address.

  • Sure. What's the spec on ABV?
    I think on my gear, getting it to spec won't be an issue its more of a question of what's the max volume through the column that maintains that spec.
    Did you run at 100% RR for long?

  • Good stuff Yurgle well done.

    StillDragon Australia & New Zealand - Your StillDragon® Distributor for Australia & New Zealand

  • wow that's great where would you need to go to get that tested ?

  • yurgles work :))

    StillDragon Australia & New Zealand - Your StillDragon® Distributor for Australia & New Zealand

  • edited April 2016

    @jacksonbrown said: Sure. What's the spec on ABV?

    Generally sold to BP in Australia (British pharmacopeia) specs which are 95.6 to 96.3 v/v I think?)

    @jacksonbrown said: I think on my gear, getting it to spec won't be an issue its more of a question of what's the max volume through the column that maintains that spec.

    Absolutely - that is the ultimate challenge for neutral. And that's the reason a lot of gin guys buy base neutral rather than make it themselves - the industrial producers just do it so efficiently.

    @jacksonbrown said: Did you run at 100% RR for long?

    About 1 hour? A lot of the time was me playing with RC water flow to find that tipping point where the vapour moves to the PC. Or "riding the clutch" to use @punkin's analogy. All part of the learning process!

  • I have done it a few more times now and am getting faster at recognising that tipping point with my gear. But on single pass whiskey and not neutral so the temps and timing is quite different.

  • Try your packed column again.
    Ride the clutch again.
    Now now find the power level that it floods at then reduce by it 10%.
    Then ride the clutch to the tipping point and don't touch the valve again...
    Now use the power to control the take off.
    The amount of reflux that you locked in shouldn't flood and the increasing vapour won't mater too much.
    Slowly raising the power will reduce the RR and increases the take off rate.
    Once the abv falls to a point just above that minimum acceptable level you just maxed out your packing.
    That's how I would do it anyway.
    Just my opinion but it seems to avoid flooding reasonably well.

  • cheers @jacksonbrown - reading yours above and @crozdog 's method of driving with power rather than RC flow is definitely worth me trying. I am still very much experimenting with methods so appreciate any advice I can get!

  • edited April 2016

    Very cool!

    I strongly suspect anyone who can competently operate a multi-plate hobby still can smash most basic alcohol GC metrics.

    Primarily, because we are running a batch distillation process - and if the still can sufficiently separate to achieve azeo, it will do a smashing job separating most other compounds, especially the major heads components - Acetaldehyde, Ethyl Acetate, etc. We can be very conservative with cuts, etc. Continuous is a whole other can of worms.

    Methanol - if you aren't running fruit, you don't stand a chance at getting near limits.

    Everything else is going to be based on fermentation quality (and probably not the recipe).

    If you are serious about neutral, I would imagine a precision thermometer and a precision hydrometer would be very useful in day-to-day operations.

    I've learned why the TTB is so particular about hydrometers - most cheap full-range hydrometers are absolutely garbage.

    Use something like a Durac B61807-7000 (189 to 200 proof) or B61807-5000 - and it's like magic.

  • Do you have the GC plot that you can share?

  • Awesome data!

    Agree with @grim on the hydrometers and thermometers... they will give you a reality check on what you think is 192 proof (prices from novatech-usa.com )


    189 to 200 Proof, Durac High Precision Alcohol Proof Hydrometer
    [H-B Instrument # 6895]

    If you need to be accurate to a tenth or two of a proof, get the Calibration cert: C60114-0000
    H-B Instrument Proof or Thermo-Hydrometer 1 Point NIST Traceable Certificate, (Each)


    30 to 124°F DURAC Plus Precision Glass Thermometer (each)
    [ H-B Instrument # 6/1124 ] $68.06

    That one is good enough, but if you are in business, get one of these you keep stored away safe to calibrate against: B60205-0700
    30 to 124°F DURAC Plus Partial Immersion Liquid-in-Glass
    Thermometer, with a NIST Traceable Calibration Certificate (each)
    [H-B Instrument # 3/4124 ]

  • edited April 2016

    Yeah, the sticker shock was why I posted the model number of the lower-priced unit.

    B61807-5000 (IRS Type R) - You can find this one for about $50usd.

    It is 0.2 divisions as opposed to 0.1 divisions, and has a slightly broader scale (185-206).

    I have some of the smaller 12" "5000" unit models, you can read them to a half a division (0.1). The bigger "7000" units have a tighter scale, very easy to read to a 0.05 precision.

    Once you temperature correct, be prepared for disappointment. :)

  • @grim said:

    Once you temperature correct, be prepared for disappointment. :)


  • cheers guys - I am in Australia I have a calibrated thermometer approved by tax office with 0.1 deg C. Only proofed with dodgy Chinese hydrometers though. I only have calibrated hydrometers from 20 - 80 ABV required to secure my licence.

    When I make another batch of neutral I will keep all recipe/yield/run figures and post with full testing incl GC plot, UV scan and evaporated residuals data. Full BP pharmaceutical testing. Maybe a month or so?

  • i should explain too - it costs nothing to get a commercial licence from the tax office in Australia. However you do have to invest in some records systems and basic measuring equipment. Given I work at a reasonably exposed level in the industry I thought I would go fully licenced just to avoid any problems for me professionally. But frankly I am hobby distiller who is just learning the ropes through trial and error. My goal is to release some small amount of product once I have something I am happy with and have a hobby that covers most of its costs! Gets me closer to an emerging good spirits scene in Australia too which is good fun.

  • Make some good stuff win a few medals make some money and be happy... :))

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