Black beers can be highly polarizing. They can be a slow mover in a brewery’s lineup, but some breweries manage to have a hit with them anyway. Many people who happily lap up espresso would never put a similarly inky beer to their lips, while others swoon over their chocolaty, coffee notes. Many wrongly attribute strength and heaviness to them. Internationally they’re a very small minority of all beers sold, but at least one country—Ireland—has had a long, monogamous affair with them.
Historically, black beers are one of the few families you can put an accurate date on. Brown beers such as early porters start to appear in the record about 1700. We know these beers were brewed from a particular type of brown malt kilned over brisk hardwood fires, often torrefying (puffing) during the process and justifying the name “blown malt.” It’s not clear exactly how dark these early porters were, but they are invariably described in contemporary references as brown rather than black.
As technology became available to measure how much sugar they were getting from each ingredient, brewers were shocked to find how little extract they were getting from their brown malt, and the search was on to replace it. Pale ale malt answered in terms of efficiency, but this left them with the problem of how to get the beer dark. After some decades in the wilderness experimenting with burnt sugar and other stopgap solutions, a man named Daniel Wheeler came to the rescue.
His invention, patented in 1818, was a drum roaster that could produce the highly colored black malt that quickly took on the “black patent” designation. Within a few years, standard recipes for porter and stout included pale and black patent malts, sometimes with some amber (biscuit) malt thrown in for toasty notes. All the old books agree that this produced a profoundly different-tasting beer. At the same time, these beers started to be described as black rather than brown. The next 150 years or more saw a slow evolution into the range of the different strengths we see today, plus some variants that featured oatmeal, roasted unmalted barley and others.
So from a flavor standpoint, what makes black beers tick? First and most obvious is the black and other types of very dark malts used in small quantities (10 percent is typical) to give the beers their color. Despite their intense color, you might be surprised at how delicate the flavors of black malts can be. This is counterintuitive until you consider the roasting process. Malts are heated in rotating drums, and as the time and temperature increase, so do the amount of color and the chemicals known as heterocyclics responsible for the toasty, roasted aromas we associate with dark malts. But at a certain point, the heat becomes great enough to blow off some of these volatile molecules, which means that while color is still increasing, aroma is decreasing. Add to this the fact that maltsters employ techniques such as water misting to lessen the harsh bitterness of their dark malts. This creates steam that draws out roasty compounds, lessening the aromatic intensity along with the bitterness.
The result is that the malts with the darkest color are the softest in flavor, with smooth dark chocolate and espresso notes. At the pale end of the roasted spectrum are the woefully misnamed chocolate malts. Rather than being chocolaty, they are often sharp and coffeelike. Rookie brewers often make the mistake of assuming the name is truly descriptive, and the resulting beers can be acrid and redolent of ashtray. Used correctly, chocolate malts can add brightness and focus to a beer. Roasted unmalted barley has a unique espresso pungency and is the defining roastiness in Irish stouts.
There are a couple of tastes specifically associated with very dark malts. First is a noticeable acidity, a result of the pH drop that occurs when roasting. This is in proportion to the quantity and type of dark malts added, but it often adds a noticeable crispness, perhaps one of the reasons black beers have traditionally been popular in tropical regions such as the Caribbean. The second taste is bitterness, as a result of chemicals called chlorogenic acid lactones and phenylindanes that build up during roasting and are commonly found in coffee as well. Roasty bitterness isn’t as clean and pleasant as hop bitterness, so most maltsters have a process for reducing the bitterness of their black malts. Some use barley that has been dehusked, which removes another source of harshness. Rye and wheat are also roasted with this in mind.
When tasting a black beer, our eyes tell us to look only for coffee, chocolate and other roasted notes. These flavors are there, to be sure, but it’s important to look beyond the obvious and focus on the other layers a brewer may have added. A stout can be brewed solely from light-colored base and roasted malts, but brewers often use a number of different mid-colored malts to add complexity and drive the overall flavor in a particular direction. There are plenty of choices: caramel malts for toffee, raisin and burnt sugar; Vienna for a sweet carameliness; Munich and melanoidin/aromatic malts for rich cookie flavors; and amber/biscuit or brown malts for toasty notes. While these specialty malts add a lot less color than the black ones, they can affect the flavor profile profoundly, something that’s important to keep in mind whether you are formulating a recipe or critically tasting.
Base malts matter as well. North American lager or pils malts will be extremely neutral and have little flavor contribution. Pale ale malt adds a crisp, crackery dryness. The heirloom malt, Maris Otter, adds quite a malty boost that makes it worth consideration. Now almost forgotten, mild ale malt was once the backbone of all British black and brown beers, adding a rich caramel base note.
In addition, many variations such as oatmeal stout use adjuncts that can bring a creamy texture that offsets the roasty bite of the dark malts. This is one of the secrets of Guinness: it uses a hefty percentage (about 20 percent) of unmalted flaked barley that contributes to the creamy body and dense foam, especially when nitrogen is added to the carbonating mix. Flaked or malted oats have a long history in stouts, probably because black beers really benefit from a creamy counterpoint to roastiness that can sometimes be a tad sharp and bitter. It also doesn’t hurt that they are cheaper than barley malt.
As long as we’re peeking behind the curtain of black malts, we should also consider fermentation character. Most porters and stouts employ a British ale yeast, which adds some degree of fruitiness. Whether or not you can pick it out above the other flavors will depend on the recipe, as the roasty aromas tend to dominate. Ale yeasts do make a beer smell different, as a comparison with a Baltic porter—a lagered version—will reveal. In that style, soft, roasty cocoa aromas dominate, and they also typically have a very smooth and clean flavor in the mouth, a result of extended cold conditioning. Belgian stouts also exist, although they are fairly rare. As you might expect, this region’s uniquely aromatic ale yeasts manage to make their presence known above the background of roast with fruity and spicy notes. Belgian stouts may also employ dark brewers’ caramel syrup, which has a somewhat different roasty character, perhaps more akin to milk chocolate.
As is so often the case with beer, porters and stouts present themselves as deceptively simple creations. Dig a little deeper and you reveal layer after layer of deep, delicious flavor beneath that inky black surface.
Randy Mosher is the author of Tasting Beer and is a senior instructor at the Siebel Institute.