I wanted to make a chiller for standard extract batches in my 5 gal. brewpot, but felt that most chillers didn't chill the center of the kettle very well, so I made this dual coil chiller with standard hardware store stuff (man the prices have gone up recently) I havn't used it yet but my H2O temp in Michigan right now is just above 40* and I ran water through the chiller from my kitchen sink at just under 2 gals. per minute, so I have no excuse to not get another batch going soon!