Refer to the input text as context and select the correct relationship between 'brewing' and 'beer' from the available options.
Options: legal form, product/material produced, operator, business division

Founder Christian Ettinger was a business student at the University of Oregon when he first began brewing beer in the early 1990s and remembers when craft or specialty beer consisted of the Killian’s Irish Red, Coors Winterfest and Henry Weinhard’s Dark, Red or Ale.
product/material produced