Review of Vanilla Custard V2 Flavor-Cap:

I have this flavor in my stash at all times & make sure to order it when I am about 3/4 of the way through the bottle because I can't live without it. It adds a yummy, creamy, buttery flavor to mixes & can really make the difference between an "ok" mix to an "awesome" one. 

I haven't made a juice with just the custard in years, so I can't recommend a tried and true % to use if not mixing with other flavors. If mixed with other flavors, the % depends on what it is mixed with. I estimate my typical recipes range from 5-7%. I wouldn't recommend more than 10%.