Progressive freeze-concentration is a method of freeze concentration with a single ice crystal formed on the cooling plate in the system. This makes the separation of ice crystal formed from the concentrated mother solution much easier than the conventional suspension crystallization method, in which many small ice crystals are formed. Tubular ice system with a large cooling surface area was shown to be effective as a method for scale-up of progressive freeze-concentration with an increased productivity and a high yield. In this method, the slower growth rate of ice and the higher circulation rate gave the lower effective partition constant as was expected theoretically by the concentration polarization model. The effective partition constant was also dependent on the initial solute concentration; the higher concentration gave the higher partition constant of solute. By tubular ice system, coffee extract, tomato juice, and sucrose solution were very effectively concentrated to high concentrations with good yields, showing the high potential of progressive freeze-concentration for practical applications. (c) 2004 Elsevier Ltd. All rights reserved.