The Impact of Grain Roasting on Beer Flavor Profiles

The short answer: kilning and roasting create malt colour and flavour through the Maillard reaction and caramelization, and at the darkest end, charring. Light kilning gives bready and biscuity notes, crystal malts add caramel and toffee, and dark roasted malts add chocolate, coffee and roast. A little goes a long way: 1% roasted barley turns an ale red, and a dry stout gets its black colour and coffee bite from about 10%.

Roast level	Examples	Flavour	Typical share
Light kiln	Vienna, Munich, biscuit	Bread, toast, biscuit	Up to 100% (Munich); 5–15% (biscuit)
Crystal / caramel	Crystal 10–120	Caramel, toffee, dried fruit	3–15%
Chocolate	Chocolate malt	Cocoa, coffee	2–8%
Black / roasted barley	Black malt, roasted barley	Sharp roast, coffee, ash	1–10%
Dehusked roast	Dehusked black or chocolate	Smooth roast, colour with little bite	1–6%

How heat creates malt flavour

• Maillard reactions: sugars and amino acids react and brown, like bread crust. They happen in the kiln, in the roaster and even in the boil, and they speed up as the temperature rises. This is where bready, toasty and malty flavours come from.
• Caramelization: sugar browning on its own at high heat. Crystal malt is “stewed” wet at mash temperatures so its starch turns to sugar inside the husk, then dried or roasted. That’s why it tastes of caramel and adds unfermentable sugar and body.
• Charring: at the darkest end, the grain starts to burn. That brings coffee, bitter chocolate, and in excess, ash and acrid flavours.

The more heat, the further along the scale the flavour moves: bread, toast, caramel, chocolate, coffee, burnt. How malt is kilned in the first place is covered in the malting process.

The dark malts compared

Malt	What it is	Flavour	Classic use
Pale chocolate	Malted barley, roasted less than chocolate	Milk chocolate, gentle roast	Brown ales, porters
Chocolate	Malted barley, roasted dark	Cocoa, coffee, a softer roast	Porters, stouts, brown ales
Black malt	Malted barley, roasted almost to charring	Sharp, dry, ashy; mostly colour	Porters; small amounts for colour
Roasted barley	Unmalted barley, roasted	Dry, coffee-like, sharp	Irish dry stout; a touch in Irish red
Dehusked black	Roasted with the husk removed (Carafa Special), or roasted wheat, which has no husk (Midnight Wheat)	Colour with little bite	Schwarzbier, black IPA, dunkel

How much to use: examples from our recipes

Beer	Dark grain	What it does
Irish red ale	1% roasted barley	Red colour and a dry finish
Munich dunkel	3% dehusked black	Deep colour; the Munich malt does the rest
American brown ale	5% chocolate	Nutty cocoa behind the crystal and biscuit
Schwarzbier	6% dehusked black	Near-black, but smooth and clean
American porter	6% chocolate, 2% black	Chocolate first, a little bite
Oatmeal stout	5% chocolate, 5% roasted barley, 2% pale chocolate	Rounded roast, softened by oats
Dry stout	11% roasted barley, 3% chocolate	Black, dry and coffee-sharp

Getting a smooth roast, not a harsh one

• Watch the mash pH. Dark malts are acidic and pull the pH down. With soft water, a stout can mash too low and taste sharp, so it may need a little extra alkalinity. See mash pH.
• Add dark grain late. Stirring it in near the end of the mash gives most of the colour with less bite.
• Cold-steep for the smoothest roast. Soak the crushed dark grain in cold water overnight, strain it, and add the liquid to the boil.
• Use dehusked malt when you want colour but not roast.
• Balance it. Roast tastes harsher in a thin beer. Flaked barley, oats or a little crystal round it out.

Frequently asked questions

Does roasted malt make beer bitter?

It adds a roasty bitterness and dryness that you taste alongside hop bitterness. It doesn’t show up in the IBU number, so keep it in mind when you balance a dark beer.

Do roasted malts need to be mashed?

No. Chocolate, black and roasted barley have no enzymes and little usable starch, so you can steep them. That’s why extract brewers can use them too.

Why does my stout taste acrid or burnt?

Usually too much black malt, or a mash pH that fell too low. Swap some of the black malt for chocolate or dehusked black, check the pH, and try adding the dark grain late.

Can I toast my own malt?

Yes, for the lighter end. Spread pale malt thinly on a baking sheet and toast it at about 350°F (177°C), checking every 10 minutes. Stop when it smells nutty and a cut kernel looks light tan. You’ll get a biscuit or toasted-bread character. Dark roasts are hard to do well at home.

Related guides

Choosing brewing malts, types of stout, porter vs stout and water chemistry.