Snow are able to grow to hundreds of micrometers or millimeters in size at the expense of the water droplets by the Wegener–Bergeron–Findeisen process. The corresponding depletion of water vapor causes the ice crystals to grow at the droplets' expense. These large crystals are an efficient source of precipitation, since they fall through the atmosphere due to their mass, and may collide and stick together in clusters, or aggregates. These aggregates are snowflakes, and are usually the type of ice particle that falls to the ground. Although the ice is clear, scattering of light by the crystal facets and hollows/imperfections mean
Ice wine temperatures around 20 degrees Fahrenheit (or -7 degrees Celsius), and press them while still frozen. Ice crystals remain in the press, while concentrated juice flows out. The resulting wine resembles ice wine. The process of "freeze distillation" is similar in its concentrating effects, although it occurs after fermentation. Typical grapes used for ice wine production are Riesling, considered to be the noblest variety by German winemakers; Vidal, highly popular in Ontario, Canada; and the red grape Cabernet Franc. Many vintners, especially from the New World, are experimenting with making ice wine from other varieties: whites such as Seyval blanc, Chardonnay,