Was the 6% on beer sales off the gross, or net? Either way, that could potentially be a lot of money if it's a busy brewpub.
It might be obvious to everyone but me, but get any profit-sharing deal like that hammered out explicitly in a contract. I went into business with people I trusted (family) because they offered a profit-sharing deal and minority ownership stake in exchange for working 80-100 hours a week for less than minimum wage. Now, a year later they've decided they don't really feel like honoring their end of the deal, and since I trusted them, I never made them sign anything on paper.