Malt & Grain

Porter owes its color to the roast level of its malt. Originally, "brown malt" dominated—a barley malt kilned over wood fires. Kilning means drying and roasting the germinated grain with heat. Brown malt turned dark brown in the process and tasted of toast with a light smoky edge.

In 1817, Daniel Wheeler patented a drum-roasting process that could produce very dark malt known as "black patent malt." This allowed brewers to add color and roasted aroma precisely, while the bulk of the grain bill remained pale malt. This cut costs, since dark malt is stronger than pale malt and less was needed. Porter could thus be made more cheaply and consistently, and the city's large breweries had the volumes to do it.

Today, a London bitter such as the one Fuller's brews in Chiswick is made mainly from English "pale malt," a lightly kilned barley malt with a bread-crust flavor. To this is added "crystal malt" for caramel sweetness, and depending on the style, a portion of "chocolate malt," which doesn't actually taste of chocolate but of cocoa and roasted bread. The word "chocolate" here refers only to the color. Anyone drinking a London porter often tastes these three malt types in sequence.

Barley dominates; wheat or rye are rare in London brewing. The large malthouses aren't located in the city itself. Their barley grows in the east and south of England and arrives as finished malt at breweries in Chiswick, Bermondsey, and elsewhere.