How may liters in a barrel of beer?

There is no standard size for a "barrel" of beer. The term can be confusing as it refers to different volumes depending on the context:

* US Beer Barrel: This is the most common meaning and equals 117 liters (31 US gallons). This is the standard size used by most breweries in the US for production and distribution.

* UK Beer Barrel: This is sometimes referred to as a "British Barrel" and equals 163.65 liters (43.2 US gallons).

* "Pony" Barrel: This is a smaller barrel often used in pubs and restaurants, holding approximately 59 liters (15.6 US gallons).

So, to answer your question, a barrel of beer can hold anywhere from 59 to 163 liters depending on the specific type of barrel.

It's always best to clarify what kind of barrel is being discussed to avoid confusion.