pH of final distillate

[Harley]

I'm adding sodium hydroxide to low wines to bring the pH to >12 to hydrolyse ethyl acetate.

But, the pH of the final distillate is ~10.5! Once it's diluted down it will sit just above 7 but are there any concerns here? What might the effects be?

I'm concerned that sodium hydroxide may be carrying across to the final distillate. Also worried about soapy texture as well.

The pH of pure ethanol is 7.3. I can always dilute and redistill to get the lower pH.

[Deplorable]

I have not read anywhere here, other than your posts about adding sodium hydroxide to the distillate. Can you point me to something that says this is a good idea? Id be interested in some reading.

[corene1]

New to me. All I have ever added to low wines is water or wash to dilute them down for the spirit run.

[Yummyrum]

The pH of pure ethanol is 7.3. I can always dilute and redistill to get the lower pH.

Not so sure. Where did you get that number from ?
In any case as home distillers we can’t reach pure Ethanol . The best we can get is azeotropic ethanol .Which has a pH around 5.5

Actually When you distill water , it too will have a pH around 5.5
It is due to there being no Ions in the distilled water and it absorbs CO2 from the air very quickly turning it to carbonic acid .

[Harley]

Reference for using sodium hydroxide in low wines: viewtopic.php?f=32&t=63038
Reference for pH of pure ethanol: https://www.jjstech.com/ethanolc2h5oh.h ... re%20water.

This is true that we can't achieve pure ethanol, but its a reference for how close we should be. My distillate is a long way off at the moment.

[Harley]

Reference for pH of distilled water: https://sciencing.com/ph-distilled-water-4623914.html

Yummyrum - that's a good pickup! Could explain why my pH is dropping by ~1.5 points from the wash to the distillate


So if you're not making your low wines alkaline (with sodium hydroxide or sodium carbonate to hydrolyse the ethyl acetate), then you should be getting a pH of ~5.5

[Deplorable]

Thanks for the links Harley. Since my quest is for whiskeys not neutrals, I see now why I haven't seen much about it.

[Harley]

Something interesting has happened.

I left my cuts for 24h to aerate and the pH has dropped from ~10.5 to 7.9 - which is very close to pure ethanol (7.3).

Anyone know what may have happened?

[Demy]

Harley, the article on water really interesting, I have always read that distilled water should be PH 7 and my distilled water is as the article says, I could not understand why .. Personally I never added anything to the low wines to regulate the PH.

[Yummyrum]

I have always read that distilled water should be PH 7 and my distilled water is as the article says, I could not understand why ..

You are not the only one . Where I work , those on a higher pay grade than me think the same . ( Too much theoretic text book reading ) .

It was my job to run the water distiller and was being questioned why it was not 7pH . At first I also queried this and thought there must be contamination occurring . Replaced all suspect hoses etc , cleaned the glass spotless ... still the same .Googled the answer . CO2 absorption .

Something interesting has happened.

I left my cuts for 24h to aerate and the pH has dropped from ~10.5 to 7.9 - which is very close to pure ethanol (7.3).

Anyone know what may have happened?

My guess is that your distillate is initially coming out so high due to puke residue you had recently when you had that reddish stuff in your distillate when you accidentally ran 92@ in your boiler with the NaOH .
It has now absorbed CO2 and lowered the pH .

Any distillate I have made has a pH around 5.5
Incidentally , its not just a quirk of using a pH meter in Ethanol. Universal pH indicator solution will show the same .

[atarijedi]

I'll just throw this out there, pure ethanol doesn't actually have a pH value. It's sort of nonsensical to ask "what is the pH of pure ethanol" because a pH value is the logarithm of the concentration of hydrogen ions in an aqueous solution. Aqueous means water is the solvent.

Pure ethanol isn't an aqueous solution, there is no water present, and so it can't have a pH value. You can stick a pH meter in it, and maybe get a value, but it won't be a useable value.

That said, if you add sodium hydroxide to low wines, you will hydrolyse esters. A base hydrolysis reaction will happen to any NaOH that isn't neutralized by any acids present. Base hydrolysis of esters is called saponification, you'd be making soaps aka carboxylic acid salts or fatty acid salts.

[Harley]

Awesome post atarijedi, and cool name
Thanks.