even without a PH meter you can rely on color change to know when to stop adding lye..
the two pictures are only one drop of lye away
it's not as obvious when working with dirty tea but there is a yellow tinge that goes away when you reach the right PH..
sodium carbonate works great though, and you don't need much unless you used a lot of vinegar. if you first do a manske on the acidic rue tea, collect the crystals, then dissolve in hot water(no vinegar), you'd only need few mls of a saturated sodium carbonate solution to properly base it, but with sodium carbonate the yellow tinge doesn't go away immediately, an insignificant amount of the harmalas stays in salt form dissolved in solution giving it a slight yellow coloration, after few hours waiting for the freebase to settle the yellow tinge will go away.
another way to know.. if the solution still has harmalas salt and you let a drop of base run on the side of the jar, you can watch it transforming those salts into freebase as it enters the solution, if there is no harmalas salt left you will see that drop entering the solution leaving a colorless trail that dissipates in few seconds..
once you reach that stage(no yellow tinge with lye, or no visible freebasing with sodium carbonate) add a few more drops.. then do a water wash or 2 and you are good
Sakkadelic attached the following image(s):
20180208_145502.jpg
(61kb) downloaded 131 time(s)."Is this the end of our adventure? Nothing has an end. We came in search of the secret of immortality, to be like gods, and here we are... mortals, more human than ever. If we have not obtained immortality, at least we have obtained reality. We began in a fairytale and we came to life! But is this life reality? We are images, dreams, photographs. We must not stay here! Prisoners! We shall break the illusion. This is Maya. Goodbye to the holy mountain. Real life awaits us." ~ Alejandro Jodorowsky