card,
We can't answer your question for many reasons:
- We don't know how concentrated your coffee extract is.
- We don't know what liquid you're adding it to.
- We don't know the new flavor you're trying to achieve.
- Even if we knew the variables above, we can't know what your subjective taste/flavor preferences are.
Start with a very
small amount of your pre-mixed
juice (say, 3 ml, which is the same as 60 drops). Put it into an appropriately-sized dripper bottle (3ml or 5ml). Add
one drop of the coffee extract. Recap the bottle and shake it well to mix/distribute the flavoring. Test by dripping two drops into an atty, then take a couple tokes. If the new flavor isn't enough or not to your liking, repeat the process, adding
one more drop of flavoring to the 3ml bottle. Mix again. Test
vape again. Continue this process
(one drop at a time) until you're happy with the new flavor.
Be patient, and remember that with flavoring less is often better than more.
Don't overdo it, since the new flavor may "bloom" after steeping and taste stronger the next day.
Once you arrive at a ratio of flavoring to juice that you like,
write it down---
x drops of flavoring to
y drops of juice. Then you can then mix a larger quantity using that basic ratio.
There's nothing sacred about 30mls.
