Cooling water temperature

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Cooling water temperature

Postby AussieCol » Sat Mar 23, 2013 2:45 pm

Well,I finally kicked the turbo yeast, AirStill, habit, did a TPW, and got the new still in "production". The still is a "compromise" 25 litre combined reflux/pot still (achieved by changing from reflux tower to pot head and vice versa). I now have the still connected by a power controller with the output into a copper parrot. I did a vinegar wash to clean the still, followed by a full rinse down. All worked fine, no leaks or issues. The boiler got running and by adjustment of the power in, with full cooling water flowing, I set the top of the reflux column temp to 78 deg C and a gentle flow of 90% ABV appeared. All fine and, having disposed of 200 ml fore shots into the "shower cleaner" jar, I monitored the continuing output.

Now to my questions - I am using a large "wheely" bin and a small pump to provide the cooling water - no running water in the vicinity of my "brewing shack". It's running at about 700ml per minute but, at a local ambient temperature of 32 deg C yesterday, the cooling water rose to a constant 48 deg C. The column temp remained steady at 78 deg C and output was at 3 to 4 drops per second at a true 90% ABV (corrected to 20 deg from 30 deg C output) for the first litre and a half and reducing after that. I stopped collecting at 40% ABV.

1. Is it OK to run like this and will the cooling water temp have any effect on the quality of the drinking stuff? - I can't freeze bottles of water to drop in the bin, as the wife has the freezer filled to capacity :0)

2. Will reducing the cooling water temp or setting the column temp a little higher enable faster collection or is this just a characteristic of my still?

3. Could I go deeper than 40% ABV by using smell, feel and taste or is there no benefit with a neutral run?

Cheers, AussieCol
Last edited by rad14701 on Mon Mar 25, 2013 7:09 pm, edited 1 time in total.
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AussieCol
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Re: Cooling water temperature

Postby oliver90owner » Sat Mar 23, 2013 3:05 pm

I would say you may as well get as much from your wash as you can but not for drinking, just for recyclng in the next run.

For the condensate, it will not matter as long as the vapours are condensed back to liquid, but if you are refluxing with a water-cooled copper coil things will be different.

Your 78 degrees at the top of the reflux simply implies the vapour is mostly alcohol and must have risen by a fair amount by the time your ABV was down to half that value - it would have risen to 100 if all the alcohol had gone.

Changing the heat input (and so product output) may well change the taste of the product while certainly changing the speed of collection.

RAB
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Re: Cooling water temperature

Postby AussieCol » Mon Mar 25, 2013 2:56 pm

OK, just to complete the story on this first run, I only managed to get 1.7 ltr output before detecting slight "off" smell and taste. For a well cleared TPW wash at 0.995 and approx 10.2% ABV I would have expected closer to 3.5 ltr of acceptable neutral spirit. Part of the problem may be that I have now been told that in a CM still you need to control column temp by water throughput, rather than power input to the element, (maker's instructions very limited) but is there anything else that I'm obviously doing wrong in reflux mode?
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