Ok, so my first round whith diy I have decided to have a go with some menthol crystals. I have filled approxamately 75% of my 10mL bottle with finely crushed(mortar & pestle) menthol crystals. The other 25% contains PG. I have heated the bottle in a hot water bath to disolve the crystals. While the mixture is hot its very standard e-liquid looking. After it cools it seems to be forming a giant chunk of menthol at the top of the bottle. I have repeated the process of heating and cooling twice with the same end results. The question is this.... If I add more pg to this batch to allow the rest of the crystals to emulsify where do I know that I have enough(PG)? The only few recipes Ive found using crystals seem to begin the same way that mine did. I am trying to get a concentrated menthol for adding to my base, not to be able to vape it straight. In addition to having something to add to my base I would like to obtain a repeatable process. Thank You for any help in advance.