The way law enforcement works is if you brought enough attention to yourself, say by getting caught selling some, your bank/debit/credit transactions would be subpoenaed along with the records of the suppliers you were found to be doing business with. You don't have to be caught with over 200 gals on hand, they just have to prove you bought enough ingredients to produce that much.
So, you bought 5000 lbs of malt and 50 lbs of hops to make 200 gals?