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Achieving 95%

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Hoping someone could lend some advice. I've been running a 3"x84" column with head condenser coils and output arm condenser. As much as I've tried I am always only able to achieve 88% ABV. My charge is a 40L 50% stripped run. My cooling water is outputting at 60 deg F. and my head temp is a consistent 172.3. Taken off at 500ml/hr after 30 min equalization. The column has 6' copper packing (rolled mesh, not scrubbers). If anyone has any ideas please share, this is really starting to get to me. Thank You

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It sounds like you need to either reduce your heat/btu input, or increase your reflux. You should have no trouble achieving 95% with a setup like that if run properly.

What's your heat source for the boiler?

How do you manage the reflux?

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First thing I would do is calibrate the thermometer, start simple. Then I would question the placement of the thermometer/probe. Needs to be directly in the vapor path as you arm takes off. I saw one install where the probe was setting in the middle of the reflux coils. Temp had to be way higher at takeoff to achieve 172 at the probe. Similar problem as yours.

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I am always only able to achieve 88% ABV... and my head temp is a consistent 172.3...

Both Swede and Porter are right on. Assuming that you're running this still near sea level at atmospheric pressure, at least one these data points is in error. If your vapor is actually at 172.3 deg F, it is at 96% ABV. If it's at 88% ABV, its temperature will be 174.5 deg F.

What does your thermometer read (a very different question from "what is the temperature") after your 30 minute equalization? If I were you, I'd fiddle around with getting that temperature reading as low as possible and keeping it as low as possible throughout the entire run regardless of its numerical value. Swede's advice should help there. If your goal is 95% ABV, and you're yielding 95% ABV, who cares if your thermometer reads 169 deg F ? Just scribble "+3.3" on it for anyone who cares and enjoy your product!

Nick

P.S. It never hurts to brush up on your hydrometer technique (assuming this is the tool you're using to determine ABV), and remember that without an extremely precise thermometer for measuring your sample, your temperature corrections will introduce a significant error. The TTB Gauging Manual may seem like overkill, but it is good technique.

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I agree with the other posters, but would like to add that alcohol will burn off at a lower temp than you think. I suggest lowering your temperature in order to allow the higher alcohols to lift off properly because it sounds to me like you are running hot. A higher temp has a tendency to draw off water with it as you approach its boiling point. The closer you are to the boiling point of water the more water you will draw across.

You can raise the temp as you get into the heart of the run, but expect the abv to drop when you do.

Also, is the alcohol level you are speaking of an aggregate amount from the total run or the beginning, middle, or end of the run? The level will vary during the run and the end result (abv) will be lower than the beginning (abv) of the run for sure.

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sorry

Dehner, do you recommend throttling back on the heat when the pressure drops? I have found, it takes a bit extra to get it flowing, but once the pressure evens out, I have to throttle back just a bit to keep it from running too hot and too fast. That way It comes out higher

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