It might be the fact that I've been sitting behind this green box the whole day but in any case I don't have an idea of how to get to ph5.

Even if I add just 1 ml of 5% (~0.05 g) acetic acid (vinegar) in 1000 ml of H20, the pH is still just (log and all) 3,9.

Is there any other option than basifying ?

why do you need to be at pH 5? You can take the pH 4 or 3 or 2...all it really means is you'll need more base when raising pH later...

You could try diluting the acetic acid to below 5% with distilled H2O, then adding a little at a time until you reach the desired pH, kind of like in a titration. If you're using true acetic acid in dH2O (not sure if off-the-shelf distilled vinegar has other impurities) and diluting with dH2O, then it should be pretty simple to calculate the amount of acid you'll need to add to get to your target pH. I'm not a chemist and I'm in no position to post the formulas, but perhaps someone else out there who likes to do these types of calculations () could help. There's probably even an on-line calculator if you Google it. It's pretty basic chemistry so there should be plenty of references out there.

-JM

jmaxton: All true but the acetic (or citric or any of the more common used ones) is too strong. For instance, if I dissolve 1g of acetic acid in 100 l of H2O the pH is 4.26.

SnozzleBerry: As I understand at pH of 6.86, 99% of the DMT alkaloids will be in salt form. 5 is choosen to have some reserve but going to 2 or 3 is just going to pull more unwanted (in this case) alkaloids (which have lower pKa's than DMT).