pH of your wash and final product?

rectifier · Post by **rectifier** » Tue Apr 04, 2006 5:31 pm

Got a pH meter from a friend to borrow on the weekend and tested through many of my spirits as well as a few commercial spirits and drinks.

They were all acid, and the level of acidity almost directly corresponded to how good they were: i.e. pH 5 rum was good, down to pH 2 (the most acidic drink in the house!) which was vile.

The rum discovered to be pH 2 tasted awful, somewhat metallic and I had noticed after running it, that the copper was very shiny inside... it had obviously eaten copper off of the inside of the still piping.

The commercial spirits were all almost exactly pH 7, leading me to believe my drinks should be much closer to neutral.

I know that you have to do your first distillation in acid conditions to avoid ammonia release from the nutrients, but how acidic should it be? I assume it only needs to be barely acidic to keep the ammonia-containing nutrients together. Does anyone test their wash, or do y'all just toss it in and distill?

I took all the acidic rums that I didn't really like and added bicarb until they were basic (this is fine for a second run, right...) and plan to run them again in hopes of salvaging them as a neutral-esqe ultralight rum spirit.

Swag · Post by **Swag** » Tue Apr 04, 2006 5:41 pm

That's interesting. I have been doing some sugar washes which I can't imagine would be too acidic.
On the other hand, I'm sure the sourmash I have been recycling is pretty acidic. But it's supposed to be so I'm not worried about it.
How does the rum taste after you put the bicarb in it?

rectifier · Post by **rectifier** » Tue Apr 04, 2006 10:08 pm

I would assume it still tastes like copper. I didn't drink any, I'm going to redistill it next weekend to get the metal ions out... and whatever "soda water" taste the bicarb brings to the table.

Edit: the burny, nasty smell that the ph 2 one had did go down quite a bit though once neutralized... this may be due to neutralization of acetic acid (which would give it a vinegar smell).

Eventually the esters will hydrolyse as well, resulting in a more neutral spirit - this is documented on the main page, though i don't remember exactly where right now.

Does anyone have an idea why there would be such discrepancies in acidity between washes with identical ingredients?

furball · Post by **furball** » Tue Apr 04, 2006 11:54 pm

Sounds like on of the washes had a few more acid producing colonies it it then the other. When you stared your yeast, did it start off vigorously or was it a bit slow to start? I can't remember what the boiling point of acetic acid is but I believe that it is in between ethanol and water and does carry over during distillation. It is an interesting experiment that your doing, now my curiosity is peeked on some of the things that I have made.

Furball

Rocky_Creek · Post by **Rocky_Creek** » Wed Apr 05, 2006 4:45 am

If you are using a potstill the second distillation will be less acidic. Can't speak for reflux stills.

rectifier · Post by **rectifier** » Wed Apr 05, 2006 9:41 pm

I always use a yeast starter but it often starts slow once added to the wash. The latest batch was the most acidic... this was also the wash started in the coldest environment and was quite slow to start.

I think acetic acid's BP is actually higher than water's - i can't remember though, and don't have time to look it up right now...