When it comes to malt flavor in beer, it's helpful to think of your grist (the sum of all grains used in the beer's mash) as a choir. The base grain fills out the risers—the core of the choir's sound—but fades into the background as bold soloists strut their stuff. Specialty grains are those soloists. And what a delicious song they sing.
Specialty grains are used primarily for their potent flavor and color properties, which can make an impact on a beer even in small quantities. Though they can provide sugar for fermentation, that quality is less important than what they can do to the flavor and aroma of the final beer. In some cases the addition of specialty grains makes a subtle difference, and in others they're the essential element of a beer's style (for example, try to imagine a dry stout like Guinness without roasted barley's smoky complexity). Want to get to know the specialty grains that might be in your beer? Read on below.
Typically, malt is made by soaking barley, allowing it to germinate, and drying it in a kiln. This malting process prepares the grain for brewing by releasing the starch necessary for mashing. But Crystal and cara malts go a bit further. Instead of drying in the kiln, the grains are essentially mashed in their husks—they are stewed in warm water to allow the starch within to be converted to sugars. Then the malt is roasted in a rotating drum (a bit like a coffee roaster) to caramelize those sugars. It's a bit like making caramel corn, and the flavor isn't that far off.
What to look for: Look for sweet toffee or caramel-like flavors in your beer—while the use of these grains affects texture and head retention, Crystal and cara malts are most easily recognizable by this candied flavor. If you taste caramel or toffee, this is the likely source. Imperial red ales (like, say, Oskar Blues' G'Knight) and barleywines (try Anchor's Old Foghorn) often display this character prominently.
Chocolate malt is made by gently roasting kilned malt to brown it. This creates a deep, roasty and bitter flavor that is often compared to—you guessed it—chocolate. Don't expect a Hershey's bar, though; in my experiences, chocolate malt expresses itself as more of a coffee or cocoa powder-like flavor.
What to look for: Chocolate malt provides a key flavor component in some brown ales, but it's most common usage is as a flavor element in porters and stouts. Look for it in Samuel Smith's Nut Brown Ale, and in any porter or stout you find in front of you.
When roasted longer, and at higher temperatures (around 400°F), chocolate malt will turn into black malt. You may also see this referred to as black patent malt due to the process being patented in the early 1800s—nowadays the terms black malt and black patent are functionally synonymous.
What to look for: Used mainly as a tool for darkening beer's color, black malt imparts an ashy or burnt flavor in beer. Present in the darkest of dark beers, you'll probably know it when you taste it. Look for Great Divide's Yeti for a pretty clear, intense taste of black malt.
Roasted barley is distinguished from the other roasted malts because, well, it's not a malt. Raw, unmalted barley is roasted at temperatures exceeding even black malt to produce this specialty grain.
What to look for: Providing a bitter, ashy, and almost smoky flavor, roasted barley is what makes a stout a stout to many people. Look for its flavor in stouts of all types; it is a similar flavor to black malt, but is generally considered to be less harsh, more complex, and slightly more sweet. It can also impart a slight deep red color to beer. If you've still got that bottle of Great Divide Yeti, look for roasted barley's flavor there. North Coast's Old No. 38 Stout, any of the Founder's imperial stouts, and yes, Guinness, all express roasted barley character in a big way.
Mimicking old methods of malt production (think pre-Industrial Revolution), smoked malts are produced by drying malt using the heat from burning wood or peat. The strong aroma of that smoke hangs around on the malt and is transferred to the beer made with it. Beechwood, applewood, and peat are the most commonly used fuels for smoking, and each has its unique character.
What to look for: If your beer tastes like you smell after a bonfire, you're on the right track. To really taste smoked malt, seek out the famous rauchbiers of Bamberg, Germany. Aecht Schlenkerla is the most widely-available brewer of these beers in the US, and some say the best. Try their Marzen, Weizen, or Ur-Bock, and you'll be instantly aware of what beechwood smoked malt tastes like. For a fun side-by-side comparison, grab their Eiche, which uses oak-smoked malt.
The world of specialty malts is even more diverse than I've discussed here, but these are a few of the most easily identifiable of the commonly used varieties. For more on how to identify the malt in your beer, start at my post on base malts, which includes the arguably-specialty Munich and Vienna varieties.
Can you think of beer examples that show what each of these types of malt tastes like? List 'em in the comments below!