I was using a counterflow chiller, doing fine and then I went to 10 gallon batches. The wort must be chilled to below 140F within 20 mins or you get DMS. With 10 gals it took to long, so I made a whirpool immersion chiller out of 60' of 1/2" copper. The wort is below 140 in 2 mins. to 65 in...