What is the difference between dubbel, tripel and quadrupel?

The names come from the Belgian abbey and Trappist breweries, where they indicated how strong a brew was compared with the light beer for everyday drinking.

The modern dubbel goes back to a beer Westmalle brewed in 1922, after the brewery had been rebuilt following the First World War. The tripel followed there in 1931.

Quadrupel is the newest term and is mainly used outside Belgium for the strongest dark abbey beer. In Belgium itself, Quadrupel is the name of a specific beer rather than a general designation.

A dubbel is usually between 6 and 7.6 percent, a tripel between 7.5 and 9.5 percent, and a quadrupel between 8 and 12 percent.

These ranges come from the Beer Judge Certification Program style guidelines and describe what is available commercially. They overlap: a light quadrupel and a robust tripel can be equally strong.

For a dubbel, typical values are around 6.5 to 7 percent. For tripel and quadrupel the spread is wider, because brewers outside Belgium interpret the names freely.

Colour comes from the malt, not from the strength. A tripel is brewed with pale malt, a dubbel with darker malt.

Expressed in colour values: a tripel is 4.5 to 7 SRM, a dubbel 10 to 17 SRM and a quadrupel 12 to 22 SRM. So a tripel is golden blond, while the other two range from amber to dark brown.

The high alcohol content of a tripel comes from a large amount of grain, or from sugar added during brewing. Sugar provides alcohol without making the beer darker.

No. Any brewer may call a beer tripel or quadrupel. There is no law and no quality mark that ties a recipe or an alcohol percentage to those names.

What you read on the label is therefore a description, not a guarantee. A tripel from another brewing tradition can differ considerably from what you find in Belgium.

What is protected is the beer's origin. That is what the Authentic Trappist Product label is for: it says nothing about style or strength, but about where and by whom the beer is made.

The label says where a beer comes from and under whose supervision it was made, not how strong or how dark it is.

The International Trappist Association sets three conditions: the product is made within the immediate surroundings of the abbey, production is supervised by the monks or nuns, and the proceeds go to the needs of the monastic community.

The association was founded in 1998 to give consumers clarity about origin and authenticity. A licence is valid for five years and is granted per product or product group. The association itself states that trappist is an origin, not a brewing style.