if you go one step deeper, the definition of drinkable is "suitable or safe for drinking", so technically, a beverage just need to be suitable for drinking but

if you go one step deeper, the definition of drinkable is "suitable or safe for drinking", so technically, a beverage just need to be suitable for drinking but it does not need to be actually drank for it to fit the definition. https://www.merriam-webster.com/dictionary/drinkable https://www.merriam-webster.com/dictionary/drinkable