In celebration of National Lager Day, Dec. 10, Samuel Adams, a brand of Boston-based The Boston Beer Co., released an infographic detailing historical facts compiled by its brewers as well as survey results compiled by Wakefield Research, Arlington, Va.

The following are some facts gathered during the research:

1. Although beer has been brewed for more than seven millennia, the first lager wasn’t brewed until the 16th century. America’s first lager was brewed around 1840, when lager yeast was brought across the Atlantic from Europe.

2. Lager yeast, as opposed to ale yeast, ferments (eats sugar to produce carbonation and alcohol) at cooler temperatures and, when done fermenting, settles to the bottom of the fermentation tank.

3. Lager yeast also takes a longer time to condition the beer than ale yeast. What’s the tradeoff for the additional weeks of waiting for a lager to brew? In the case of Samuel Adams Boston Lager, it’s the extra hop in the aroma and a smooth, refreshing finish, according to The Boston Beer Co.

4. Due in part to their smooth, crisp character, lagers are sometimes labeled as plain and boring; however, Samuel Adams brewers found results contrary to this sentiment. Craft lagers are flavorful and complex, and a number of different styles fall under the lager category, including Oktoberfest, Baltic porter, Vienna lager, bock, double bock and rauchbier, among many others, the company says.

5. Before modern refrigeration, brewers needed a way to keep their lagers cool during the brewing process. In lieu of today’s larger cooling tanks, German lager brewers of old sometimes cooled their beer in Alpine caves or in cellars dug deeply into hillsides.

To learn more about lagers, click here to view the infographic.