All crafted foods are green (or higher) while found and vendor-purchased foods are white.

So why are crafted potions the same white color as vendor-purchased and dropped potions? Especially since there is such a huge gulf of difference in quality between the crafted and non-crafted potions?

Having them all be white makes it hard to see at a glance in your inventory which item is junk, and it makes it harder to find the right potion type in a guild store.

(Bonus: Do the same thing you already do with food and drinks: make single-effect crafted potions green, dual-effect potions blue, and triple-effect potions purple. To make it easier to tell the difference between a single-effect health potion and a tri-stat potion.)