Fine tuning the Fractioning Process.

birdwatcher · Post by **birdwatcher** » Tue Dec 05, 2006 5:24 am

Since moving to my present location, one point, re the fractioning process bothers me and I would appreciate some opinions. That is, the decision when to begin collecting ethanol. i.e. the temperature.

The altitude of my location is about 1400 ft above sea level. I therefore believe the ideal temperature to draw off ethanol from my system would be about 77.4 C.

Stone says that the ideal point is when the temperature remains constant for about two hours around this point, bearing in mind that atmosperic pressure will also have some bearing.

I am today, as I type this. collecting at 77.1C. In the past I have collected as low as 69.9 to as high as 77.8. The product appears to be perfect in this range.

I always stop collecting when the temperature rises above 80 C and I draw off heads as the temperature rises until constant to the above range.

Opinions please re temperature range. Thanks

G

Stillhead · Post by **Stillhead** » Tue Dec 05, 2006 7:52 am

I think it also depends upon the quality of your instrumentation. If you are using a k-type probe the error is 1%. If you are using an oven thermometer the error is usually -+2deg. This would mean that an oven thermometer is not really capable of reading to three significant figures, even if it is showing the one tenth place. Bearing this in mind, you are registering a change with your probe that is constant and valid for your purposes, but it will not be possible to compare this data unless we all switch to k-type probes or something equally accurate.

The comparison of accuracy and precision require advanced reproduceable equipment.

Your thermometer is precise, but not accurate, so it registers a change well but that change may be off (kind of like shooting arrows at a target and always hitting the same spot, but the spot is never in the centre of the target).

Post by **theholymackerel** » Tue Dec 05, 2006 8:23 am

I would like to suggest that a distillers nose and toungue are FAR better precision instruments than a thermometer.

The same wash or mash recepie, usin' the same yeast, fermented at the same temp, will result in a slightly different mix of alcohols each time. So why worry about a thermometer except as an "idiot gauge" that tells ya to start smellin'/tastin'?

Stillhead · Post by **Stillhead** » Tue Dec 05, 2006 8:24 am

I am currently building a parrot stem. You may want to measure your runs by alcohol % as well as temp., as temp alone may not be the most reliable way.

Check this link http://homedistiller.org/dtw.htm and scroll down, you will find info on it. There is also a correction table file that you can download.

junkyard dawg · Post by **junkyard dawg** » Tue Dec 05, 2006 10:12 am

what mackerel said.

Post by **Grayson_Stewart** » Tue Dec 05, 2006 4:33 pm

I have a thermometer and use it on every run, but I agree totally with Holy. The thermometer is just a backup, double check, warm-fuzzy, crutch that I use to further gauge the run. I check smell and taste through the entire process and compare it to the temperature. It's different all the time, but in the same ballpark. Depending on the kind of run you are making, it doesn't take too much on the front or back end of a run to ruin the hearts...so never depend completly on the temperature probe.

When you are sitting around enjoying the product, you aren't using a thermometer as a swizzle stick...you are using your nose and tastebuds to enjoy your drink...so use them while collecting.

muckanic · Post by **muckanic** » Tue Dec 05, 2006 8:45 pm

Thermometers have always worked well for me on small lab stills, but not on anything bigger. In other words, using temperature to take cuts is fine - as long as the thermometer is measuring what you think it is measuring.

birdwatcher · Post by **birdwatcher** » Tue Dec 05, 2006 8:52 pm

Lots of food for thought guys.

Many thanks.

G

birdwatcher · Post by **birdwatcher** » Wed Dec 06, 2006 4:27 am

Stillhead wrote:I think it also depends upon the quality of your instrumentation. If you are using a k-type probe the error is 1%. If you are using an oven thermometer the error is usually -+2deg. This would mean that an oven thermometer is not really capable of reading to three significant figures, even if it is showing the one tenth place. Bearing this in mind, you are registering a change with your probe that is constant and valid for your purposes, but it will not be possible to compare this data unless we all switch to k-type probes or something equally accurate.

The comparison of accuracy and precision require advanced reproduceable equipment.

Your thermometer is precise, but not accurate, so it registers a change well but that change may be off (kind of like shooting arrows at a target and always hitting the same spot, but the spot is never in the centre of the target).

---------------------

Yes, I use digital thermometers now. Meat thermometers, one from Canadian Tire(long white), another from Home Hardware(black,round)

I've often wondered if the steam(vapour), just above the copper mesh, is the same or slightly less than the actual liquid, boiling below. I would have thought lower.

And if so, a probe into the liquid would make sense.

Opinions?

G

birdwatcher · Post by **birdwatcher** » Wed Dec 06, 2006 5:08 am

Grayson_Stewart wrote:I have a thermometer and use it on every run, but I agree totally with Holy. The thermometer is just a backup, double check, warm-fuzzy, crutch that I use to further gauge the run. I check smell and taste through the entire process and compare it to the temperature. It's different all the time, but in the same ballpark. Depending on the kind of run you are making, it doesn't take too much on the front or back end of a run to ruin the hearts...so never depend completly on the temperature probe.

When you are sitting around enjoying the product, you aren't using a thermometer as a swizzle stick...you are using your nose and tastebuds to enjoy your drink...so use them while collecting.

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I'm pretty careful. When I enter the hearts, I set aside say 500 ml for a future rerun. The same when I depart the hearts i.e as soon as the temperature suddenly increases past say 80 C.

When I'm bleeding off the heads, I do use smell(nail polish remover) and discard. I will try taste as suggested. I have smelled the tails(God awful), but this has never been a problem, as noted above, as I have stopped retaining product, before or just as the tails appear.

This is the great value of this forum. Because of the secretive nature of this facinating hobby(study), sometimes, what may appear obvious to some is an unanswered question for others, regardless of experience. And the answers are not nessesarily found written down. The personal touch is required.

I appreciate your assistance and do my best to assist others when I can.

Cheers,

G

G