A typical method of beer taxation in Scotland would involve higher tax rates on stronger or higher quality, beers. "50 Shilling Ale" would be your typical run of the mill Scottish style ale. "60 Shilling Ale" a little better, etc. "Boscos 90 Shilling Ale" would be, of course, off the charts.
Scottish-Style Export Ale
Boscos Brewing Company
Memphis, Tennessee