Now we contemplate one of the most powerful ingredients available to brewers—powerful in its ability to deliver dramatic flavors as well as striking appearance. Now we contemplate the dark arts.
The last time I wrote here about dark beers, I focused on everything except the darkest malts (“Beyond ‘Roasty’: The Surprising Psychology of Stout,” beerandbrewing.com). Here, the focus is on the malts that deliver much of that striking color and those roasted flavors for which stouts and porters are famous.
Almost all malt flavor derives from a couple of chemical reaction systems: Maillard browning (aka non-enzymatic browning) and a similar but distinct process known simply as “caramelization.” Maillard involves many forms of carbohydrates plus nitrogen-containing amino acids found in malt. Caramelization mainly involves sugar—typically in a dense and liquid state, like when you put sugar in a pan and heat it until it browns and changes flavor. At the highest temperatures, however, a process called “pyrolysis” takes over, which is just a fancy technical way of saying “burning”— of sugar molecules, specifically.