Premise: The Mayfield Brewery was a brewery that operated in Mayfield, California between years 1868 and 1920. The brewery was located at what is now the corner of California Avenue and Birch Street in Palo Alto, California. The brewery produced Steam beer and sold it in kegs to local saloons. The brewery was shut down by Prohibition.
Hypothesis: Steam beer was the most popular beer in the late 1800s.