(cryo referring to very low temperatures), French term, now used more widely, for freeze concentration, the controversial winemaking practice of artificially replicating the natural conditions necessary to produce sweet white ice wine. Freshly picked grapes are held overnight in a special cold room at sub-zero temperatures, −5 or −6 °C (21 °F) for example, and then pressed immediately. The freezing point of grape must depends on its concentration of sugars, so only the less ripe grapes freeze. pressing the grapes straight out of the cold room therefore yields only the juice of the non-frozen, ripest grapes, whose chemical composition remains unchanged. The colder the grapes are kept, the less but richer juice is obtained, and vice versa. The wine producer can therefore manipulate how much wine of what quality is made (unlike ice wine, which is entirely dictated by natural conditions). The technique is particularly useful in wet vintages in which the health and ripeness of individual berries may vary. In the late 1980s some Sauternes properties, including Ch d’yquem, experimented with the technique.