Question about my boka

[jabrone]

I've been running a boka with a 2" column for a couple of years now. Overall I've been pleased with the results. Yesterday, I was doing a run and the abv was a bit lower than I'd expect (about 90%). I surfed around on this forum and ran across an old thread where someone suggested to increase the heat in the boiler. I did that and it was the first time I'd ever really seen what the still could do. The abv increased right away and it stayed that way until the end where it suddenly and dramatically dropped off.

Probably a real novice question but why does increasing the heat in the boiler help increase the abv of the product? Seems counter-intuitive. Just curious and would love to know why.

[StillerBoy]

You don't mention the take-off rate, nor the amount power used.. the rate of take-off has a direct effect on the purity level by reducing the reflux occurring in the column.. power effect the amount of vapour produced in the column for refluxing.. with a LM setup (which is what a boka is), the more refluxing within reason, with a reduced take-off rate, the higher the purity level abv..

Probably a real novice question but why does increasing the heat in the boiler help increase the abv of the product? Seems counter-intuitive. Just curious and would love to know why.

This line of thinking apply for a pot still setup.. the pot in manage by the power used to maintain the amount of take-off, which in turn the purity level.. where in a LM setup, power and take-off are manage in relation to each other to provide the purity level abv..

Mars

[der wo]

Because it's a LM. If you increase the heat, you produce more vapor, but the output remains same (because it's a LM. The heat input has no effect on the output rate). So you send more back into the column and get a higher reflux ratio, more redistillations.
The maximum heat you can use is limited by the diameter of the column and the type and density of the packing.

[StillerBoy]

The maximum heat you can use is limited by the diameter of the column and the type and density of the packing.

And also by the condenser's ability to condense the vapour..

Mars

[der wo]

Yes,
but if the condenser is the limit, your design is flawed.

[StillerBoy]

but if the condenser is the limit, your design is flawed.

Agreed but it is all part in the management of the unit when in-operation for the final product..

But this we do not know, for the OP has omitted info that would assist in answering his concerns..

Mars

[jabrone]

This line of thinking apply for a pot still setup.. the pot in manage by the power used to maintain the amount of take-off, which in turn the purity level.. where in a LM setup, power and take-off are manage in relation to each other to provide the purity level abv..

Mars

This was my overall problem. Still thinking like I'm using a pot still. Thanks for all the input.

[StillerBoy]

LM management setup operate on a combination of the power, column packaging, condenser water flow, and take-off rate.. these are the items one has to learn to balance or dial in for the type of finish product you are looking for.. LM management setup will produce from a very high purity neutral and all the way to very good favour product, once the understanding of these functions are understood and applied..

Mars