I'd have to side with the non-business school gguys, especially if you don't expect to be the next Sierra or Lagunitas. Having spent a decade successfully running a small business with nothing more than high school education and several decades in the blue collar trades, I understand that either you are the kind of person who can run a business or you aren't, no amount of schooling will ever change that. I too am working towards ruining my life by starting a brewery and am far more concerned with the learning more about the art of beer making than I am in perfecting my skills at driving a pencil.
I'd imagine that the folks on this forum who are professional brewers would tell you that brewing in a commercial environment bears little resemblance to home brewing, I could of course be wrong. At risk of offending the folks with MBA's, the majority of the most successful small businessmen I've know had no formal business education, but they did have a healthy dose of good sense. If you can manage your personal finances you can probably handle the business aspects of running a small business. It aint rocket science - or bio-chemistry either.