I don't know where to really post this thread, moderators please move it where you deem appropriate.
** Background **
In the recent past I fermented and stripped four still charges, and for each time I got around 5 litres at around 38% alcol ABV.
Today I wanted to dilute and re-strip the stripped material (I would like not discuss why now). I put the 20 litres at circa 38% ABV and I diluted it with tap water to circa 40 litres. I therefore have around 40 litres at 19% ABV in my kettle, which is around 8 litres of anhydrous alcohol.
** What I am seeing today **
After reaching production I eliminated some 200 ml and then put the big vessel under the condenser. I am only stripping, or so I told myself, so I just collect everything from now on.
As you might have inferred, I am working to obtain a very-neutral neutral, and so I wanted to avoid smearing also in this second-stripping run. Instead of stripping it at full power as I did in the four previous single batches, I wanted to strip at a slower speed.
I am now producing very slowly and steadily. My kettle is firmly "stuck" at 86,5 °C, and my elbow temperature is 73,4 °C very firmly.
Now I know the mantra "you don't make cuts by temperature". Yet, I tasted the product. Quite strong and unpleasant. Even the grappa method of just spreading it on the back of the hand (37°C) and smelling the hand gives an unpleasant smell. I took away the large vase and put again the small graduated vessel which I used at the beginning of the run.
I then took a cylinder and floated a alcoholmeter in it: I am collecting at 89% ABV.
The question arises: how can it be that, starting from a 19% charge with a pot still, I am collecting 89%? I suspect the answer is: there must be a lot of reflux. Or is it normal?
My still is so composed:
- Electric stove which is running at 2 of 4 levels of power (I might measure the Wattage if important);
- Kettle which has a volume, to the brim, of 42 litres or so;
- a 2" sight glass;
- two 50cm elements, 2", making an elevation of 1 meter, without any packing, isolated with cork;
- An elbow where I measure the vapour temperature (non-isolated);
- A final condenser.
As one can see, the pot still is a pot still in the obvious sense that it has no packing and no intentional reflux, but it is probably a "column" in the sense that I do presume, for what I understand, that some reflux is happening here.
If that is the case, this is because of the sheer length of the vapour path. I do nothing to cool it.
Also, I am still watching the process, tasting, etc. but I suspect I will have to re-insert the big vessel for the collection only when this high-ABV high-stink has passed.
