What is Reinheitsgebot and why does it matter? Well, it's also known as the "German Beer Purity Law", and it has come up recently because German brewing companies are protesting against using hydraulic fracturing for natural gas exploration in Germany because they are afraid it will contaminate water sources and put them in violation of this purity law.

This story may sound made-up, but there is something for investors to gather from it: the struggle to produce gas is much greater than we think. Several countries have banned the practice of hydraulic fracturing outright, and those who allow it are struggling to produce. In this video, Fool.com contributor Tyler Crowe looks at some of the recent struggles to get Europe's shale gas industry off the ground and what it means for investors here in the U.S.