All of these do absorb liquids very well because of the soft terry cotton tops that most of them have. Moisture is absorbed to keep it away from the person sleeping in the bed rather than repelled from the cover. None of the manufacturer product descriptions address the subject of hot or cold liquids on these. It is assumed that all of the liquids will be warm, cool, or body temperature. Hot liquids such as hot coffee or tea would almost certainly damage these covers and make them unusable for waterproof purposes again.