Complex sentence: While at first, most modern brewers were small operations, by 1890, the first substantial, industrial brewing facility in the country was built in Monterrey (Cervecería Cuauhtémoc).
Split into simpler sentences: While at first, most modern brewers were small operations. By 1890, the first substantial industrial brewing facility in the country was built in Monterrey (Cervecería Cuauhtémoc).