A diverse range of foods are aerated, using a similarly varied assortment of processing methods. Aerated foods are generally poorly understood, but are of increasing importance as manufacturers seek to exploit the novelty and versatility of bubbles as food ingredient. Food aeration is one of the fastest growing unit operations, while many ingredients achieve their functionality through their effects at bubble interfaces. This paper reviews the range of aerated foods, and attempts to bring some structure to their diversity by examining different bases for classification. Experimental approaches for characterising aerated foods are discussed. Although food foam chemistry is reasonably well understood, the physical behaviour of bubbles in food systems is less well appreciated. Models describing the dynamic behaviour of bubbles as physical entities are reviewed. (C) 2000 Elsevier Science Ltd.