I do that quite a bit, especially when I'm running low. I don't actually measure anything though, so all I can give you is some guidelines. Basically, spice isle extracts work pretty well. Especially if they are PG base(alcohol and water base work well to). I also use Rose water in some mixes(very little, it's potent). I like using Vanilla Extract w/ a little rose water. Very pleasant, kinda dreamy. LorAnns Keoke Coffee is my fav. Really easy to mix, just maybe 5% Keoke flavor to VG, adjust viscosity w/ water. I have also made an orange blossom tea flavor. Orange extract, rose water, pepermint, vanilla and a little LoRanns carmel flavor. Yummy, but a bit perfumy. I am a long time cook, and I just like to mix to where the flavor is a bit to strong to taste on it's own(then vape a couple drops to check it). Being that there is no nic, tasting a little bit won't hurt you. You can make your own coffe extract by using the Tasters Choice singles, mixed w/ about 5ml of hot water. Then let it sit over night. Very potent and cheap. Adding a little sucralos(Splenda) to the coffe "extract" is a good idea. Pina Colada=Coconut extract, pineapple extract, LorAnns carmel(small amount). I even added a little almond extract, kinda added a rum flavor. Some other ideas: You can go to a wine and beer making shop and get flavorings designed for cordial making. I made a scotch flavored 0 nic
juice that was VERY pleasing, and a very true taste. It is Alcohol and PG based and vapes very nicely. Exhale is much like the exhale of a good scotch and water. I have a bunch of other cordial flavors that I haven't plaed w/ yet. Waiting for my nic
juice(I miss the nic when it's not there). Oh, also, the longer you let the
juice sit after mixing the better. And I recomend the best Pure Vanilla flavor you can get, it is worth it. If I think of anything else I'll post back.