- Apr 11 5:29 PMMy problem has been resolved.
After checking all equipment it was found that the digital thermometer must have received a knock and whilst appearing to be operating correctly was actually giving incorrect temperatures.
It has now been re-calibrated and worked perfectly on the last just finished distillation.
Thanks for your assistance.
--- In Distillers@yahoogroups.com, "Harry" <gnikomson2000@...> wrote:
> --- In Distillers@yahoogroups.com, "alaray_992000" <carsonar@>
> > Sorry for my lack of information.
> > My system and procedures are as follows.
> > I brew 2 brews of 57 litres each containing 12 and a half kg
> > and 3kg Sugar. This is brewed with Heat Wave yeast. Each 57 litre
> > stripped giving 17 litres (34 litres total) for the 2nd
> > The still is 60 litre S/S with a column of 1.15 metres x 50mm S/S
> > packed for stripping and for the 2nd distillation a 1.95 mitre x
> > S/S column packed with Structured Pure Copper Mesh Column Packing
> > with a gap of 100mm from the return pipe from the offset head to
> > top of the packing.
> > The still is heated by a 2400 watt element controlled by a Helios
> > controller which allows me to strip at 100% and then on the 2nd
> > distillation turn power down to 30%. I reflux normally between 30
> > 50% heat settings. My 2nd distillation gives me an output of
> > 13 and 14 litres at 94/95%. I re-distil any distillation below 93%.
> > In the past things have gone well with output of 95% for 13 litres
> > with top of column temps reducing from 80at start to as low as 76
> > during distillation. I am at a loss as to why I could not get the
> > of column temp below 86. To my knowledge I did not deviate from
> > normal procedures.
> Sounds like you're doing everything right. Looking for
> The temp at the top of the packed column is an indication of the
> ratio of [ethanol : water] vapours passing the probe. At 86°C
> measured, it's somewhere around 75% ethanol to 25% water (assuming a
> binary mix for simplicity. It's not, as there are minute amounts of
> other substances involved, but I digress...).
> Now this is fine for a flavoured spirit (e.g whisk(e)y or rum) but
> not good enough for GNS or vodka. And it's certainly not good enough
> for a packed-column reflux run.
> To increase purity (therefore separation) in a 50mm Ø you need to:
> A. Increase the coolant flow
> B. Decrease the product takeoff
> C. decrease the energy input
> A combination of A & B will increase the reflux ratio, thereby
> improving separation. 'C' is necessary if you are overdriving the
> still, creating more vapour than the still column was designed to
> It's entirely possible that your controller has developed a fault and
> you may be applying more power than you think. I find it suspicious
> that in previous runs the temp was dropping below the BP of ethanol.
> This indicates either a LOT of heads or not enough power being
> applied to maintain the boil. From your above description of the run
> in question, I'd be checking the accuracy of the controller with a
> multimeter. Some of them are not designed for continuous duty cycle.
> Also check the coolant system for correct operation. There may be a
> blockage of some sort restricting flow and upsetting reflux ratio.
> Let us know the results.
> regards Harry
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