Johnny6 wrote:When entering your "fudge factor", what would you actually enter for azeotrope into the calculation? Is the value in percent, or would the value be 0.0031 for azeotrope?

I've been curious about the contribution of altitude/ambient pressure into the calculations. Thanks.

Does anyone have the formula to go the other way? So that if i was to take a vapor temp measurement, i could convert it to an ABV in exel without having to physically reference a chart

Tokoroa_Shiner wrote:Does anyone have the formula to go the other way? So that if i was to take a vapor temp measurement, i could convert it to an ABV in exel without having to physically reference a chart

I have a calculation for functions based on the dataset from vle-calc. The two sets of coefficients for step distillation calculations are:

6th order Liquid EtOH vs Deg C (For 0 to 98% EtOH, R2=.99999)
C6=2.02354E-10
C5=-6.43224E-08
C4=8.52833E-06
C3=-0.000635847
C2=0.030177921
C=-0.999296544
b=100.0713473

5th order Deg C vs Vap EtOH Above 78 Deg C (From 78 to 100 Deg C, R2=.9991)
C5=-0.000127261
C4=0.05654474
C3=-10.04471396
C2=891.6069096
C=-39542.4145
b=701024.354

If you start at 8% liquid ABV, you can find the boiling temp by using the first (6th order) equation.

Hint = 93.7 Deg C

Then find the vapor % EtOH by inserting the temp result into the second equation (5th order).

Hint = 48.7%

You can keep using the same two sets of equations to loop down until the R2 error causes trouble near azotrope.

rad14701 wrote:... from the Distillation Theory section of the parent site based on the formulas provided by Tony Ackland on the Calculations page...

I'd be curious to see a quick runthrough on how the graphs were generated, please. Or at least a copy of the tabular data. Thanks.

The formula is duplicated with different temperatures to get values which are then graphed... The actual spreadsheets might be kicking around in one of the topics... Mine is starting to look like a hack job due to all of the extra graphs I've rendered from subsets of data for my own use... Not sure what you mean by run-through... Are you looking for a step by step of how several of us figured out how to render the graphs...??? Doing so is beyond the scope of these forums...

rad14701 wrote:
The formula is duplicated with different temperatures to get values which are then graphed...

I could be blind (not the first time I've missed the wood because of all the damn trees I the way) but I don't see a formula for obtaining ABV from temperature orvice-versa.

rad14701 wrote:
Are you looking for a step by step of how several of us figured out how to render the graphs...??? Doing so is beyond the scope of these forums...

Yes, or the raw data. Your graph of vapour vs ABV matches my observations by measurement. I take 100ml at a time and measure ABV with a float, and note the temperature. As a curiosity, I'd like to make a digital thermometer which reads in ABV instead of degrees and I thought your calculated data might make for a better set of interpolation points than my measurements.
Your raw tables are all I need if you still have them, please.

rad14701 wrote:
The formula is duplicated with different temperatures to get values which are then graphed...

I could be blind (not the first time I've missed the wood because of all the damn trees I the way) but I don't see a formula for obtaining ABV from temperature orvice-versa.

rad14701 wrote:
Are you looking for a step by step of how several of us figured out how to render the graphs...??? Doing so is beyond the scope of these forums...

Yes, or the raw data. Your graph of vapour vs ABV matches my observations by measurement. I take 100ml at a time and measure ABV with a float, and note the temperature. As a curiosity, I'd like to make a digital thermometer which reads in ABV instead of degrees and I thought your calculated data might make for a better set of interpolation points than my measurements.
Your raw tables are all I need if you still have them, please.

The formula is on the parent site... And unless I'm mistaken there is an alternate formula in one of the related topics here in the forums... I'll have to check and see if I've ever uploaded the spreadsheet I used...

Maritimer wrote:If you download the other file, which is a scan of the original document, you'll see the headers. The introduction is also very interesting.

"This site can’t be reached 136.145.83.33 took too long to respond."

Here's some charts that i made. Contrary to most other charts floating around the web, you get to see the measurements (as tiny dots) from which the curve is derived, and can judge the fit on your own. The data comes from ISBN 3921567017, page 184-186. They reference this here as the original source:

The conversion of mole fraction in the original data to %vol was done considering volume contraction, by implementing the formula for density suggested in this pdf.

Thanks Prairiepiss, Is there an EASY way to get the temp of the boiler that does not have a thermometer?

Isnt the temperature of the charge predictable as displayed on the chart? Meaning that based off the %ABV of the output, you can determine the temp of the still contents?
Therefore if you're monitoring the ABV output throughout the run, can you not determine the temp of the remaining charge in the pot?

Now, in a pot still with a thermometer in the vapor path. you know the still is going to start to produce vapor at about 173f ( under perfect atmospheric conditions). How relative is that temperature at highest point in the vapor path relative to the charge temperature? Can I correctly assume that the temp of the charge is the same as the temp of the vapor at the highest point in the still (with 0 reflux)? Do I need to factor in temperature loss across the height of the column?

Use all your senses, and its not that hard. You just have to pay attention.

If your still provides no rectification, the temperatures of the vapor at the highest point and in the boiler are the same. But normally also potstills provide a small amount of rectification. So the temperature at the highest point will normally be lower than in the boiler.

In a pot still the liquid and vapor temp are the same once the heatup stabilizes and the column comes up to temp. You can correlate the output ABV and use the chart to determine both the liquid temp & liquid ABV as well as vapor temp & vapor ABV. When this finally clicked for me it was a bright light lighting up and "shining" the way lol... No more parrot and much less use of the proof and tralle hydrometer... I do use a vapor thermometer at the top of my riser and keep one of those charts handy to know how much ethanol is left in the boiler and when it get's close to 212*F I stop the stripping run. From there on a spirit run I can use detailed notes from prior tuns of specific recipes to determine where I made cuts before and test the theory that I can make cuts at the same place and test my ability to call it on the fly....

Cheers!
-jonny

————
i make stuff i break stuff
water into whiskey into water
just getting started in home distilling - been drinking for decades
16g copper pot still, 10l alembic, and a column or two
————

In a pot still the liquid and vapor temp are the same once the heatup stabilizes and the column comes up to temp. You can correlate the output ABV and use the chart to determine both the liquid temp & liquid ABV as well as vapor temp & vapor ABV. When this finally clicked for me it was a bright light lighting up and "shining" the way lol... No more parrot and much less use of the proof and tralle hydrometer... I do use a vapor thermometer at the top of my riser and keep one of those charts handy to know how much ethanol is left in the boiler and when it get's close to 212*F I stop the stripping run. From there on a spirit run I can use detailed notes from prior tuns of specific recipes to determine where I made cuts before and test the theory that I can make cuts at the same place and test my ability to call it on the fly....

Cheers!
-jonny

True!
But as a correction for your specific still (column, bridge, condensor) you could make a graph of the temperature and the percentage at the same time.
I find my thermometers have a slight difference and my cooler has a delay.
You can make graphs especially for your own specific still.