Hops started being used along the Rhine river in Germany around the 10th-11th century. It took some time before the use of hops was written into the Purity Law to ensure the quality of beer.

Because German beer would keep longer, it could be distributed further. With wider distribution, the beer could be made in larger batches. Larger batches meant it could be made more cheaply (per unit) which allowed German beer to compete against local breweries.

The early edge the Germans had in incorporating hops into their ales and beers gave them a competitive advantage that would last for centuries, and a brewing culture that thrives to this day.

Incidentally, the invention of calculus made trade easier as most beer (and pretty much everything else too) was carried in wooden barrels. Since barrels were hand-made they would often have slightly different sizes. Calculus made it easier to calculate the volume of the container to ensure the seller and customer would get a fair deal on the trade.

Hops (Humulus lupulus) are also closely related to the cannabis plant.

I'll stick with just the cannabis and skip the beer entirely then.