In the late 1960s, a molecular theory of sweet taste was proposed, based on the presence of a ?functional structure? in all sweeteners, eliciting the sweet response via the interaction with a complementary tripartite site in the taste bud receptor. Remarkably, the role of water as a likely mediator, through hydrogen bonding, between the sugar and the receptor has been almost totally neglected. Looking at the hydration shells of carbohydrates like cellobiose (tasteless), glucose (sweet), and trehalose (moderately sweet), we have observed that water molecules are H-bonded to specific sites of cellobiose and glucose, while almost no H-bonding has been observed between water and trehalose. We wish to look at the hydration shells of two sugars, lactose and sucrose, to seek for an explanation, at the atomic length scale, of the sweet taste chemoreception.