See Coffee, added by Baristacrat, Xenochemistry in the Paranormal Investigator skill tree, and the Fell Bottle, added by Grave Digger. Baristacrat offers the best example to test with as: Coffee drops regularly Coffee with Baileys, a booze item, does always stack properly, giving some contrast Reloading the game makes all existing drops from previous sessions fit on one stack, while new drops for that session must be on their own stack.
