This is my flash chiller. It is made to cool beer on its way to a font. The beer is pumped through the stainless steel coil. You can vaguely see the ice bank on the copper coil, surrounding water. The water is normally pumped, by the green pump, along the beer snake, to keep the beer line cold. I pump it around my fermenter instead. I can get my fermenting wort temperature down to about 4C.