You probably know that a sommelier is a wine expert, but you might not know that there are different levels of expertise, with the “Master” title being the highest. Not all sommeliers are masters, and the process of becoming a Master Sommelier requires years of preparation not unlike the rigorous process of obtaining a medical degree.

The process of becoming a Master Sommelier is so rigorous only 273 have earned the title since 1969, and the test has a pass rate of just 10%. To even apply for the diploma, hopefuls must pass the introductory, certified, and advanced examinations, and have experience running a wine list and educating others about wine.

Candidates then take an oral theory exam about the roles of a sommelier and a tasting exam in which they must correctly identify the type, region, and year of production of six wines. Finally, they must prepare a complete wine service including using the correct glassware, decanting the wine, and answering customers’ potential questions.

However, these exams simply scratch the surface of the knowledge a Master Sommelier must have about roughly ten thousand grape varietals in the world. While candidates have three years to finish the tests or they have to start over, Master Sommelier Christopher Bates said his journey for the title took 12 years.