This is a test of commonsense. Complete the next sentence:

How to serve and enjoy guinness
Choose the right glass.
Although it may seem that any glass will do, to enjoy a truly perfect glass of guinness you must use a tulip glass.
The shape of a tulip glass is perfect for allowing the nitrogen bubbles to circulate from the bottom and back up to the top.
Although any size will do, a 16 oz glass, otherwise known as a pint, is generally agreed upon as the classic size for the drink. Pour the drink into the glass at a 45 degree angle.