Purification media and methods of preparing purification media. A method of producing a purification medium, the method comprising the steps of (a) contacting plant fibres with a superheated fluid; and (b) processing the plant fibres into a particulate form, is described. A purification medium obtained by said method and a method of removing contaminant compounds from a liquid using said purification medium are also described. The methods and/or purification media are particularly useful in beverage production/purification.