Zahur will decant potions into 4-dose potions for free. Players can either talk with her or use her right-click Combine option. She will decant all the potions in the player's inventory, noted or unnoted, into 4-dose potions.
Upon completion of the hard or elite Desert Achievement Diary, Zahur will make unfinished potions for you for 200 coins per potion. You can take noted herbs and vials of water and she will give you noted unfinished potions in return.