Let's first start with Killians. Here are the results of comparing Killians against every other beer:

37 / 18 means that 37 people prefer Killians over Molson. Killians only wins one of the four pairings, and is therefore not the winner. Now let's look at Molson:

Molson doesn't win any pairings; clearly it is not the winner. Comparing Samuel Adams with every other beer yields the following results:

Samuel Adams lost when compared with Meister Brau, and therefore does not win. Next we look at Guinness:

Guinness only wins half of the time; it is not the winner. Finally, we compare Meister Brau against every other beer. Here are the results:

Meister Brau wins every match-up. Therefore, it is the overall winner.