# Calculators for Distilling

## Recommended Posts

You know when you are making beer there are calculators for everything. Distillers have very few, hell i have yet to find a good mash calculator as corn is not on any of them.

So i have a 600 gallon bourbon mash i want to do a stripping run on i plan on collecting all the way down hot and fast no cuts till i got 20%abv out of the parrot. So how do i calculate to determine about how much volume to expect? Now logic tells me i have 600 gallons x 8.5% = 51 gallons of alcohol, but i wont be collecting 100%. My range coming out will start somewhere around 85%ABV and Finishing at 20% ABV. My target is overall of the collection to be about 35%. What would you expect this to yield in volume.

Now i have already done this and i know what i ended up with. I want to know:

1. why is there not stripping run calculators

2. What to expect on a stripping run so i have a receiving tank that can accommodate this

##### Share on other sites

Those numbers are assuming 100% of alcohol is recovered which is never really the case. With that math, you would expect 145 gallons at 35% though - (51x100)/35 OR (100/35)x51. Redundant, I know, but it helps to be OCD when checking numbers.

I'd imagine there aren't any calculators because there are too many variables, and too many ways to interpret/misinterpret your actual alcohol content based on hydrometer/refractometer readings.

##### Share on other sites

So I used my snap 51 digital hydrometer to take accurate readings out of the parrot. my first runnings came out at about 82% I stopped at 20% and ended up with a hundred gallons of 37.7% collective. I felt this was short in volume

##### Share on other sites

@Georgeous What you have achieved is very close to the theoretical numbers.  The 51 gallons of alcohol you started with looks right.  If you stripped until the spirit in the parrot was at 20 abv then (assuming no reflux was being used) the theoretical strength of the spirit in the still should have been 2.5 abv.  Ignoring the shrinkage, if you took of 100 gallons of distillate there was 500 gallons left in the still at 2.5 abv.  This would make 12.5 gallons of alcohol left in the still.  If you started with 51 then the distillate should contain 51 - 12.5 = 38.5 which is very close to what you achieved.

The reason there are no easy-to-use calculators for these calculations is that the calculations are simply too varied.  You can get process simulators that are really aimed at the petrochemical industry, but would handle these calculations, but they are horrifically expensive - typically more than \$100,000 and only the largest engineering contractors have them.  And they have specialist engineers to drive them.

• 1

##### Share on other sites
2 minutes ago, meerkat said:

@Georgeous What you have achieved is very close to the theoretical numbers.  The 51 gallons of alcohol you started with looks right.  If you stripped until the spirit in the parrot was at 20 abv then (assuming no reflux was being used) the theoretical strength of the spirit in the still should have been 2.5 abv.  Ignoring the shrinkage, if you took of 100 gallons of distillate there was 500 gallons left in the still at 2.5 abv.  This would make 12.5 gallons of alcohol left in the still.  If you started with 51 then the distillate should contain 51 - 12.5 = 38.5 which is very close to what you achieved.

The reason there are no easy-to-use calculators for these calculations is that the calculations are simply too varied.  You can get process simulators that are really aimed at the petrochemical industry, but would handle these calculations, but they are horrifically expensive - typically more than \$100,000 and only the largest engineering contractors have them.  And they have specialist engineers to drive them.

so my 100 gallons of 37.7ABv is = to 38.5 gallons of 100 ABV?

##### Share on other sites

No, what I was trying to say was that within the accuracy of your measurements and my theoretical calculations the results are effectively the same.  I don't know how precise your 600 gallon and 100 gallon measurements were, but I suspect there would be some inaccuracy there.  Certainly my theoretical calculation was not very accurate.  For a start I totally ignored the shrinkage that occurs when alcohol and water concentrations change.  I made a couple  of simplifying assumptions to make the calculations easier and quicker.  My gut feeling is the 37.7 proof gallons that you calculated is probably within 1 gallon of the true value.

##### Share on other sites
6 hours ago, Georgeous said:

1. why is there not stripping run calculators

Hillbilly stills has a distillate to water calculator that will give you a good ballpark number.  Keep in mind that the numbers provided are theoretical and assume you have collected 100% of you ethanol.

##### Share on other sites
2 hours ago, meerkat said:

No, what I was trying to say was that within the accuracy of your measurements and my theoretical calculations the results are effectively the same.  I don't know how precise your 600 gallon and 100 gallon measurements were, but I suspect there would be some inaccuracy there.  Certainly my theoretical calculation was not very accurate.  For a start I totally ignored the shrinkage that occurs when alcohol and water concentrations change.  I made a couple  of simplifying assumptions to make the calculations easier and quicker.  My gut feeling is the 37.7 proof gallons that you calculated is probably within 1 gallon of the true value.

Meerkat, i did not have 37.7 proof gallons, after the stripping run  i have 100 gallons of 37.7%ABV product

##### Share on other sites

Isn't a proof gallon a tax concept defined as one gallon at 100 proof (50% ABV)?

In which case I think you'd have 37.7 * 2 = 75.4 proof gallons for tax purposes.

##### Share on other sites

@Georgeous Sorry, my bad.  @Eud is correct.  The 37.7 gallons are gallons of absolute alcohol and not proof gallons.

But the conclusion remains the same.  I calculated from theory and got 38.5 gallons of absolute, compared with your actual measurements of 37.7 gallons of absolute.

##### Share on other sites
On 3/20/2019 at 8:36 AM, Georgeous said:

2. What to expect on a stripping run so i have a receiving tank that can accommodate this

Hillbilly Stills calculator - you can use it in this way to determine your receiving tank size

##### Share on other sites
8 hours ago, Eud said:

Isn't a proof gallon a tax concept defined as one gallon at 100 proof (50% ABV)?

In which case I think you'd have 37.7 * 2 = 75.4 proof gallons for tax purposes.

so based on this formula i got from ttb

Converting U.S. gallons into proof gallons for ta﻿x purposes:
1. Multiply U.S. gallons by the percent of alcohol by volume.
2. Multiply by 2.
3. Divide by 100.
My calculation:
1. 100 U.S. gallons x 37.7% alcohol by volume=3770
2. 3770 x 2=7540
3.7540/100= 75.4 proof gallons

seems low to me. i was expecting higher volume. i actually collected right at 100 gallons of 37.7 % abv. i use a snap 51 digital alcohol meter to get the final reading.

so yes you are correct EUD, but what i am asking is what should i have ended up with? i thought from 600 gallons i would of stripped out a lot more.

##### Share on other sites
7 hours ago, meerkat said:

@Georgeous Sorry, my bad.  @Eud is correct.  The 37.7 gallons are gallons of absolute alcohol and not proof gallons.

But the conclusion remains the same.  I calculated from theory and got 38.5 gallons of absolute, compared with your actual measurements of 37.7 gallons of absolute.

gotcha, but my question in the end is:

if starting with a mash of 600 gallons at 8.5% ABV and my target is to stop collecting at 20% ABV in the parrot for a spirit run targeting 35% ABV of the collective. What volume in Gallons not proof gallons should i expect to collect?

##### Share on other sites
6 hours ago, Thatch said:

Hillbilly Stills calculator - you can use it in this way to determine your receiving tank size

Ok well this is what i was looking for. i came up short about 38.4 US Gallons providing this calculator is correct. Now my Anton Parr Digital Hydrometer has an accuracy of .1. so if i continued to collect to a 35% collective and not stop at 37.7 i may have hit this target

So now i have to redistill to do my cuts. i am now afraid that 100 gallons of stripping run collective is too small for my 600 gallon still, thoughts?

##### Share on other sites

If you want to improve your yield, you should collect lower than 20% abv.

Meerkat has it covered, all the alcohol you estimated is accounted for, its just that you left it in the still because you had about 500 gallons of mash at 2.5% abv, down from your 600 at 8.5%.

On 3/20/2019 at 10:48 AM, meerkat said:

@Georgeous What you have achieved is very close to the theoretical numbers.  The 51 gallons of alcohol you started with looks right.  If you stripped until the spirit in the parrot was at 20 abv then (assuming no reflux was being used) the theoretical strength of the spirit in the still should have been 2.5 abv.  Ignoring the shrinkage, if you took of 100 gallons of distillate there was 500 gallons left in the still at 2.5 abv.  This would make 12.5 gallons of alcohol left in the still.  If you started with 51 then the distillate should contain 51 - 12.5 = 38.5 which is very close to what you achieved.

The reason there are no easy-to-use calculators for these calculations is that the calculations are simply too varied.  You can get process simulators that are really aimed at the petrochemical industry, but would handle these calculations, but they are horrifically expensive - typically more than \$100,000 and only the largest engineering contractors have them.  And they have specialist engineers to drive them.

• 1

##### Share on other sites
12 minutes ago, Georgeous said:

Ok well this is what i was looking for. i came up short about 38.4 US Gallons providing this calculator is correct. Now my Anton Parr Digital Hydrometer has an accuracy of .1. so if i continued to collect to a 35% collective and not stop at 37.7 i may have hit this target

So now i have to redistill to do my cuts. i am now afraid that 100 gallons of stripping run collective is too small for my 600 gallon still, thoughts?

Couple questions:

1. How are you calculating volume? If it isn't by weight and proof you may be off by several gallons depending on several factors.

2. What kind of still are you running? What is your target ABV off the parrot? Most stills that I'm aware of recommend not running them under 1/2 volume if not more. If you have a pot still and shooting for 70% you will have to do several stripping runs to meet that half-way point. If you have a column still that can give you a decently high proof from a 8% charge, diluting the one stripping run down will be enough.\

This is the main reason some distilleries will often have 2+ stills. A larger stripping still and a smaller 'finishing' still that will accommodate the stripped volume.

##### Share on other sites

I was looking at the Hillbilly Stills calculator linked by @Thatch to try to understand why their numbers were so different from mine.  The main difference between the calculations is that I had 2.5 %abv left in the still heel, but the Hillbilly calculation would give 0.5% in the heel.  My calculation assumed that you were using a pot still without any trays or reflux, and then worked back from the 20 %abv ending strength in the parrot to get the heel strength.

But then I calculated what strength you would get in the parrot at the start of the run and it  would be impossible to get 82 %abv from a 8.5 %abv mash.  I guess this means that you are using some trays and reflux in your still.  This is one of the difficulties in designing a calculator - every still is slightly different.

I can see that the Hillbilly calculator would be very useful, so I tried to understand what it is actually doing.  It seems that it is based on the assumption that 95% of the alcohol in the original mash is recovered in the distillate.

Because of the virtual impossibility of being able to model every possible still configuration, to be able to calculate the volume split between the distillate and the heel you need 4 bits of information.  These are the volume and strength of the initial mash, and the strengths of the distillate and of the heel.  The Hillbilly calculation asks for only the first 3 items and it calculates the heel strength internally by assuming that 95 % of the alcohol is recovered as distillate.

If it is reasonable to be able to estimate the 4 items I have listed, it would be very easy to make a spreadsheet to calculate the quantity of distillate and remaining heel.

##### Share on other sites

Seems that most all of the "calculators" associated with websites that sell products to home distillers and hobbyists tend to radically overstate product yield.  Not sure that it should be a surprise.

##### Share on other sites
14 hours ago, Georgeous said:

i am now afraid that 100 gallons of stripping run collective is too small for my 600 gallon still, thoughts?

You are likely correct but only the still manufacturer can tell you for certain.  Our stills, one that is direct fire and the other a baine marie require at least a 1/2 charge.

##### Share on other sites
6 hours ago, Thatch said:

You are likely correct but only the still manufacturer can tell you for certain.  Our stills, one that is direct fire and the other a baine marie require at least a 1/2 charge.

Well I have a 600 gallon still with a 5 plate column  I also was told by my manufacturer to use a half charge. so now I'm at the Dilemma  do I take my hundred gallons and add 200 gallons of water and run it through the refracting columns ?

##### Share on other sites
44 minutes ago, Georgeous said:

do I take my hundred gallons and add 200 gallons of water and run it through the refracting columns﻿﻿﻿﻿﻿﻿ ?﻿﻿﻿

Yes.

##### Share on other sites

Is there any reason why you wouldn’t strip more than one batch before you do a spirit run?

Also, with 5 plates available, why didn’t you run it single pass?

Also keep in mind that you likely may not be able to use 5 plates on a whiskey strip - as you’ll easily be above 160 proof - unless you add a lot of water.

• 1

##### Share on other sites
2 hours ago, Georgeous said:

Well I have a 600 gallon still with a 5 plate column  I also was told by my manufacturer to use a half charge. so now I'm at the Dilemma  do I take my hundred gallons and add 200 gallons of water and run it through the refracting columns ?

Follow @Silk City Distillers questions and advice.  He'll get you going to the right direction.  BTW, we do many stripping runs on our baine marie prior to doing a spirits run on our direct fire.

##### Share on other sites

Keep in mind, if you are fermenting and distilling on the grain, you need to remove the bulk volume of remaining grain from the total volume to calculate an accurate alcohol yield.

600 gallons of grain-in fermented wash, with 1200 pounds of grain, at 8.5% is not 51 gallons of absolute (100%) ethanol (600 * 8.5% = 51), because you need to net out the weight of the non-alcohol containing grain solids that are hitchhiking along.

At worst case, 1200 pounds of grain into 600 gallons yields 100 "gallons" of solids, and 500 gallons of alcohol laden liquid.  Now, this is the worst-case - we've converted a good portion of grain starch to sugar in the liquid, so that weight needs to be removed, but grain germ, pericarp/endocarp, husk, bran, protein/fiber/fat, etc - these need to be removed from the volume - they are taking up considerable space, but do not contain alcohol.

Realistically, you'll be somewhere between 43 gallons of absolute, and 51 gallons of absolute.  You can get very clever here, by estimating the non-starch component of your mash-bill and adjusting as necessary.

Just for conversation, let's split the difference - say realistically somewhere around 47 gallons of absolute as the max.

##### Share on other sites

For giggles, collect deeper on the next run, you'll see that even if you run to 0% on the hydrometer, you won't make it to 51 if you are running grain-in (unless you underestimated your starting gravity of course).

## Create an account

Register a new account