I really like this mod but today I found a simple duplication bug for the tannin bottles.

How to reproduce

• hold multiple tannin bottles as a stack in your hand
• right click on a barrel to fill in the tannin

Result

The barrel is filled, you get an empty bottle but you keep all the tannin bottles.

Suggested fix

Either fix the mechanic or make the tannin bottles non-stackable. This would also fit more into the vanilla minecraft bottle system.

By the way...

I realized that you're using your own bucket item instead of the forge's generated one. I know this has advantages but for compatibility with other mods it would be nice if the forge's item is used. Then we could use tannin as a normal fluid in fluid systems or fluid recipes.

A similar error occurs when emptying barrels with a bunch of glass bottles