Brown Sugar is any sugar that has a brown color because of the presence of molasses, whether added or naturally present. Most brown sugar available in the United States is made by adding molasses to processed white sugar. In many other countries, brown sugar is usually minimally processed and has a naturally brown color.
Brewing with natural brown sugar made from sugar cane dates back to early colonial times when the highly prized sugar cane plant was successfully transplanted from India into the Americas and the Caribbean Islands by Spanish and Portuguese traders.
As early as 1558 the German beer writer and scholar Jacob Theodor Von Bergzarbern (also known as Tabernaemontanus), in his Botanical Encyclopedia, describes how the English often suspended a mixture of sugar, cinnamon, cloves, and other spices in a sack into beer. Tabernaemontanus also mentions that in Flanders when making or serving beer the use of brown sugar was commonplace.
In his 1889 book The Curiosities of Ale and Beer, Charles Henry Cook (writing under the pseudonym John Bickerdyke) points at a popular prejudice against sugar derived from the love of English people for the historic drink made of malt, but he also states that there is no fault in beer made with the addition of sugar, although it does give different flavors than malt. It is worth noting that brown sugar, like other forms of sucrose, rarely adds much in the way of sweetness because it is highly fermentable. It does, of course, add to the gravity of the wort and therefore can fortify the strength of the resulting beer.
Naturally brown sugars include dark muscovado and rapadura, which are made from sugar cane juice that is boiled and simply crystallized. Muscovado is usually found in the form of large damp crystals, whereas rapadura, popular in South America, is usually dried into a formed brick. These sugars are very flavorful and can add notable earthiness to dark beers. Demerara and turbinado sugars are tan-colored and usually made from cane juice that is evaporated, crystallized, and rinsed in a centrifuge to remove some of the molasses “impurities.” Turbinado sugars tend to have relatively mild sugar cane flavors, but demerara sugars vary widely depending on the origins. They can be quite mild or very complex, adding earthy flavors reminiscent of rum, fruit, and tobacco.
Processed brown sugar generally adds a much simpler, more predictable flavor to beer, allowing it to be used regularly without much fear of variability, although when used in beer it tends to lack the depth and charm of naturally brown sugars. Cane sugars are generally preferred, but brown sugar is also made from sugar beets.
Many craft brewers use natural brown sugars to add interesting flavor notes to beers ranging from Belgian-inspired golden beers to very dark stouts. South American craft brewers have taken a particular interest in their indigenous forms of brown sugar. Presented in oddly shaped cones, slabs, crystals, or blobs, specialty sugars can give a touch of tropical terroir to a beverage otherwise made with ingredients grown only in temperate climates.