Beer is 95% water. If your water's chemistry is not correct for the beer you are brewing, you will not be able to brew your best beer. Professional brewers have known this for centuries. Back in the days when chemistry was not understood, brewers learned very quickly that their water might brew great dark beers but lousy pale beers or vice versa. Without any knowledge of how to adjust the water these brewers just brewed the beer that their water allowed them to brew. That's why some regions of the world are famous for one style of beer, like Ireland...
This quick video just about sums it up. If you love homebrewing you will love Home Brew Con! Plus it's in Minneapolis this year!
Fermcap S is a great product to help eliminate boil overs and blowoff. Just watch this short video and be amazed.
Take 2 minutes to learn all about this excellent value in a Grain MIll.