91% iso should work, confirmed via g-rated confirmation bias machine 
Depends on partition coefficient in denaturant I would assume. Something like bitrex may not matter, but heptane (for instance) has a fairly high affinity for cannabinoids. At 5% I would not expect it to effect things a whole lot, so unless you’re trying to achieve quantitative data, I’m guessing nobody will know the difference. Except and until they made up a fresh batch with a different solvent, and even then…
Menaing all types of THC will show no color when tested?
Im going to use it to determine when the least amount of cbd is left when converting to d8.
Is there a different indicator test that will show d9 and other THC’s separately?
Im looking into measuring the optical rotation but for now this will do just fine.
I’m sure there is…
This isn’t to show THC more so as it’s there to detect for CBD
Edit: TLC plates
Look at fast blue stains
Usually used on TLC but ya might could just spot on sillyka… like ya can do with bromocresol green and decarboxylation
I found a pretty good read on this. I dont know how up to date it is.
[UN bulletin]
(UNODC - Bulletin on Narcotics - 1974 Issue 4 - 003)
Seems like a lot of different (color) indicators will react with cannabinoids.
Look at TLC plates (Thin Layer Chromotagraphy)
no distinction between cbd and thc for those dyes though
Much better than guessing especially without in house analytics - but even if you have those this would still help to narrow down at which point in the rxn to do a test.
The koh test can show an approximate concentration of CBD and the optical rotation can compare different molecules or approximate concentrations of those molecules
I made the test and i only get results when the whole rxn and wash was done. I tried couple of time’s during the rxn so i could tell if it need longer our not. But no succes during the rxn.,… but after wash and spd you put a few drops on your oil and you can see a reaction when the purple shows 
Its fun to do i pulled all my rxn of the shelfs, and my labrapports to see what color would turn up and must say it’s spot on 
Only during the rxn would be a perfect indicater for rxn time. Gues it has to do with the acid? still in the rxn?
You should be able to get results during the reaction. How are you taking your sample? if its by draining from the bottom of your reactor then you are probably only testing the water and acid as its going to drain out first.
Now if you are taking the sample from the top and not getting results it may be due to your reaction being to diluted and you just need to drop a little more of your KOH solution on it.
Thanks for your responce!
Yeah i been taken out lots of samples from the rxn vessel. And put a bit of Koh on it and after no reaction a lot on it also nothing so i really think becource its so diluted can not think of a different option.
Then i was thinking does mu koh not working but tested that on finised oil with cbd in it and it turned purple so also that was not the case.
As always never give up, and try a different angle 
Wanna enlighten us a little more on your process, maybe something will pop out as a reason why.
What solvent is this done in and what ratio? not sure it would matter but what catalyst.
I made the KOH like discriped 70 ml ethanol with the 4 grams of KOH and stir it well and add 30ml more ethanol. So thats a working product.
Then when the reaction is in full swing onder argon gas and with fosfor and ethanol. I take out a bit with a long straw put it on a piece of paper and drip the KOH on top but nothing happens… this is so wierd becource finised oil it works in like 5 seconds. So what i am thinking now is get more product out and add it to a test tube add some more ethanol and more KOH to the tube and shake well.
I woud try taking a few ml’s out of your reaction and putting it in a test beaker or vial, then do a few drops and swirl a little. You do not wanna shake it a bunch as it will give improper results.
Equal parts of RXN and alk beam solution worked for me.
Get some disposable pipettes too.
So going 50/50 ill give it a go thank you for the info 
Just wanted to share an alkaline beam test time-laspe I did today because I mixed up two jars of hash and didn’t want to do a bioassay. Mixed up 100g EtOH 5g KOH and there was 0.25 g of extract in each 1.5 dram vial.
think this is a very important point. I also started to play around with KOH Beam Test, to determine if my rxn is finished (CBD → d9 via pTSA). As I usually use TLC, I found this method to be much easier and less time consuming.
I took rxn samples, mixed it 1:1 with 4% KOH solution and looked for purple indication. In the beginning of the rxn it is obvious, but if the rxn comes to its end, I do have troubles to say wether it is finished or I need to go a little further.
I reread this topic and I think I made the mistake to shake the beaker for too long. This way I got purple indication that lead to the suggestion of “high CBD amount” left.
So the correct way woild be to add the KOH solution to the rxn sample, shake it for 2 seconds and look for color. How long do you usually wait to compare the color? 5 sec?
If you leave it for too long, it turns dark purple anyway.
But if you are going for high d9, at a certain point, the ratio of d9->d8 is higher than CBD->d9.
Am I really able to determine the “sweet spot” via Beam test? I think this will never be colorfree when aiming for high d9, since some CBD will always be left. If CBD has been fully converted, I will end up with high d8.
Therefore the goal should be a little purple and not colorfree
Since I excessively chaked the beaker in my last rxn, I still had dark purple indication and it turned out to be like 40/60 d8/d9 with a minimum of CBD left.
Shake for just a few seconds.
All my samples eventually went purple when I let sit for a few minutes and I believe it has to do with the KoH “breaking down” the RXN.
How long do you wait to compare color?