Seth's Correction Equation

Hey, I was reading on the gotmead forums and I saw someone make the mistake of claiming that the final ABV of his step fed mead was simply the difference in gravity multiplied by a constant. In essence, he did not account for the dilution caused by his honey.Anyways, I decided to come up with an easy to use equation to take care of this issue

The context of this derivation will be in my next post.

Here is what one of our fellow mazers posted

This is what I did

6 lbs meadowfoam honey
6 lbs buckwheat honey
6 lbs dried organic mission figs(chopped)
2 lbs dried organic Turkish apricots

Put the 3 lbs of each honey into fermentation bucket add water to 3 gallons. I mixed until all honey was dissolved. Added 3 lbs of figs and 3 campden tablets. 24 hours later the og was 1.083. I pitch 71b. At SG 1.075 I added .2 gallons of honey to bring sg up to 1.093. Then at Sg 1.05 I added .125 gallons of honey to bring the OG to 1.06. At Sg 1.005 I fortified 2.5 gallons of the mead that is just north of 14% abv with .5 gallons of aguadente to bring the mead up to an abv of just over 20%. 24 Hours later added 2 lbs of chopped mission figs and 2 lbs of Turkish apricots.

The correct solution will be in the next post

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% alcohol = alcohol volume/total volume

alcohol = step 1 + step2 + step3

( OG-FG)*125= %alcohol gain per step
Step1

( OG-FG)*125= alcohol gain per step

[(Alcohol gain per step)/]100*current volume = alcohol gained per step.

This may be re written as (OG-FG)*125*current volume /100

This is simplified into (OG-FG)*1.25*current volume = alcohol per step

So, to formulate this all out nice and pretty for your case

[(OG1-FG1)*1.25*volume1]+[(OG2-FG2)*1.25*volume2]+[(OG3-FG3)*1.25*volume3]

this can be simplified once again into

1.25{[OG1-FG1]*vol1+[OG2-FG2]*Vol2+[OG3-FG3]*vol3}= TOTAL ALCOHOL

So finally it is time to plug in some numbers

1.25{[1.083-1.075]*3*+[1.093-1.05]*3.2*+[1.06-1.005]*3.325}

This gives us .43 gallons of 100% alcohol in your 3.325 gallons of mead.

As we have discussed above % alcohol is Alcohol volume/Must volume *100

(.43/3.325)*100 This gives you 12.93% alcohol by volume before fortification.

When you added 1 half gallon of 50% alcohol this contributed .25 gallons of pure alcohol.

To get your final ABV we shall adjust our recent calculation.

He is fortifying 2.5 gallons.. 2.5*.1293=.32
[Total Alc/Total volume]*100= abv

[(.32+.25)/(2.5+.5)]*100 =19%

According to my maths you have 19% alcohol

THUS



125{[OG1-FG1]*vol1+[OG2-FG2]*Vol2+[OG3-FG3]*vol3......}/Total Volume=ABV

Hi Seth,
I'm a long ways away from figuring the math calcs like you are doing. Been somewhere around 50 years ago. So, I really am not following everything you are saying, but agree with it. The only thing that stuck out for me is when you are adding the 50% alcohol to it are you allowing for the other 50% (Isuppose water??) Just wondering, Arne.
Btw, I am impressed you can figure that out, I don't have a clue, lol,A.

Thanks, I posted this here because I figured it would be usefull. Hopefully this will get some more attention soon.

Yes I did factor that in. It is included in here [(.32+.25)/(2.5+.5)]*100

The .32 is the gallons of alcohol contributed from the yeast. The .25 is half of a half gallon. ie the pure alcohol from the distillate.

The 2.5 is the volume from the wine. the .5 is the volume added from the distillate.

In all honesty the BIG BOLD equations are the ones that most of you will find useful. However, I also included my derivation.

Arne said:

Hi Seth,
I'm a long ways away from figuring the math calcs like you are doing. Been somewhere around 50 years ago. So, I really am not following everything you are saying, but agree with it. The only thing that stuck out for me is when you are adding the 50% alcohol to it are you allowing for the other 50% (Isuppose water??) Just wondering, Arne.
Btw, I am impressed you can figure that out, I don't have a clue, lol,A.

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'

BTW, now that I bolded the key equations is that easier?

seth8530 said:

'

BTW, now that I bolded the key equations is that easier?

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Probably should be, but by the time I get thru all the figuring I imagine I would have the whole batch drunk up. LOL, Arne.

So he is off by 1%?

Eh the math is pretty easy actually. And yes, he was off by 1% abv. However, he would of been off by a whole lot more if he wasnt using something as sugar rich as honey.

BTW, I would like to note that the factor of 1.25 can be substituted for 1.31 depending on which abv equation meets your fancy.

Where can we get the app for this? WVMJ

As of right now their is not an app. But I could write a spreadsheet or .exe if their is enough interest in it.

Arne said:

Hi Seth,
I'm a long ways away from figuring the math calcs like you are doing. Been somewhere around 50 years ago. So, I really am not following everything you are saying, but agree with it. The only thing that stuck out for me is when you are adding the 50% alcohol to it are you allowing for the other 50% (Isuppose water??) Just wondering, Arne.
Btw, I am impressed you can figure that out, I don't have a clue, lol,A.

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You think you are a long ways off, I got you beat, I don't even have a clue to what the ( funny X ) is. wish I could understand this, guess I will just do it without the allowance for added solution, and just give up a % or 2. if I got that close gee I think that high ABV would not matter about 1 or 2%..

even the Government allows a 1% variance on commercial wines