The foam, or head, of your beer acts as a net of sorts for the volatiles in your beer after you pour. Beer’s volatiles include compounds such as hop oils, spices, fruity esters and fermentation byproducts. These compounds are a vital part of your beers aroma, and using a glass that promotes a healthy foam head allows your foam to capture as many of the volatiles as possible. The large rim on the tulip glass is designed specifically to promote a healthy head, meaning your beer’s volatiles will stick around.
So, what beers should you be pouring into your tulip glass? Beers that have a bright aroma and healthy head, as the tulip glass will enhance the aroma better than any glass in your bar.