Black malt is a misunderstood grain. Written off by many early homebrew authors as yielding burnt, sometimes ashy flavors, and an acrid aroma, it’s actually a fairly mildly-flavored malt, given its extreme color. Because a large amount of the aromatic compounds developed during kilning are vented from the kiln, black malt has a subdued aroma compared to other darkly-roasted grains — something a simple sniff test will show you. Because our sense of taste is highly influenced by our sense of smell, the relative lack of aroma to black malt means that it tastes milder than one might expect. Once you understand the actual properties of black malt, you will have an edge over homebrewers who refuse to use it, or don’t understand what it really adds to a beer.
The relatively smooth roasted character of black malt can blend in nicely with other dark malts. Conversely, the aroma from the other dark malts will enhance the flavor of any dark beer made with black malt as the predominant dark grain. I’ve found that black malt works well with roasted barley (500 °L), chocolate malt, and a blend of those two. And if you want to bump up the color and roast flavor in a beer, but not the aroma, black malt is a great choice. [If you want to add more aroma, use roasted barley (500 °L) or a dark chocolate malt (350–450 °L).]
A few ounces of black malt in a 5.0-gallon (19-L) batch can be used to “round out” the dark grain profile of a brown porter, brown ale, dark bitter, or other “mellow,” not-too-roasty dark beers. You can also use debittered black malt if you want to absolutely minimize any sharp edge. Unlike roasted barley, black malt also adds color to your foam, if that’s something you’d like.
In higher amounts, the sharp roasted “bitterness” of black malt can give a nice edge to a robust porter or imperial stout. For example, I use a fair amount in my Colby House Porter, blended in with the other grains.
The best example of a commercial beer using all black malt unfortunately isn’t made that way anymore, but you may remember it. Black malt used to be the only dark grain in Sierra Nevada stout, which gave it a nice roasted flavor, and showed that you do not need to limit yourself to tiny amounts of black malt in your beers. For a 5.0-gallon (19-L) clone of the old version of Sierra Nevada stout, you’d use about a pound of black patent. The current version of Sierra Nevada Stout is made with a blend of four dark grains, according to their website.
Black malt can also used to round out the flavor in a beer made with a lot of dark crystal malts. A hint of roast along with the characteristic flavors of dark crystal malt can work well in anything from dark bitters to old ales.
One obvious use for black malt is when you want to add color without a lot of roast flavor. Black malt is usually around 500 °L, so it adds lots of color to beer (and foam). However, the restrained aroma means the roast flavor is harder to detect than that of roasted barley (500 °L), which smells in some ways similar to coffee. In a 5.0-gallon (19-L) batch, you can use up to 2.0 oz. (57 g) of black malt and get almost no roasted flavor. Above 3.0 oz. (85 g), it starts to become a distinct flavor.
Some schwarzbiers use black malt, or debittered black malt, to add color — but relatively little flavor to the beer. A schwarzbier can be thought of as a Pilsner with enough dark malt to darken the color of the beer dramatically, without producing a strongly roasty flavored beer. Other schwartzbiers use malt coloring agents, which are often made from black malt (or its equivalent).
Black malt is a very dark grain. Just looking at it, it’s easy to believe that it would add burnt flavors and an acrid aroma to your beer, but it doesn’t. Give the malt a sniff next to other dark grains to understand the differences in levels of aroma between these grains. Try adding or swapping in some black malt for other dark grains in your dark beer recipes to get an idea of what it brings to a beer.
And finally, don’t be too quick to substitute debittered black malt for black malt — the astringent “bitterness” of large amounts of black malt can give a nice edge toa roasty beer to keep it from being too smooth and insipid. Black malt is used in robust porters for this very reason. In a robust porter, you don’t want a smooth, brown ale-like roast character, you want the roast character to stand up to the high hopping and be a little “sharp.”