What Gives Guinness Beer That Iconic Black Color?

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Whether or not you’re Irish or like stout beers, you’ve probably tried Guinness at least once if you’re a beer drinker, perhaps while attempting to “split the G.” The iconic Irish beer is brewed in Dublin and is known for its deep, almost-black color and for the thick head of frothy foam on top. But how does a beer with such a surprisingly light taste get such a dark color?

“From the roasted barley,” Colm O’Connor, Guinness Brewery Ambassador, told Chowhound. The barley, which is sourced locally within about 80 miles of the Dublin area, roasts for two and a half hours, giving it an extremely dark color that translates over to the beer. “We have complete control on how we roast our barley,” O’Connor said, likening the process to roasting coffee beans. O’Connor added that Guinness works with more than 300 barley farmers in Ireland, who sow the barley seeds in March and harvest them in August. Guinness takes the process of its barley partnerships so seriously that it even has “Barley Awards” after each growing season. “Farmers that can combine efficiency with quality … are rewarded for this, and that’s a big thing,” O’Connor said.

The barley roasts at varying temperatures

Chowhound

For Guinness to get that signature color, raw barley must first be roasted to just the right shade. The process starts at 374 degrees Fahrenheit, and the barley roasts for two hours. “The other 30 minutes then, that’s when the master also really kind of comes into his own,” Colm O’Connor said, “whereby he’ll take periodic samples, and make sure that it’s getting the right color.” In that last 30 minutes, the temperatures are first raised to 437 degrees Fahrenheit for between 15 and 20 minutes, then raised again to 450 degrees Fahrenheit for a final 10 minutes.

Once the barley is properly roasted and has that ultra-dark color, it’s combined with hot water to form a mash. From there, the mash is boiled alongside hops to create a liquid mixture known as “wort.” The wort then goes on to ferment along with yeast, then matures to develop flavor. Finally, it’s nitrogenated (infused with nitrogen and carbon dioxide) to give it that signature creamy mouthfeel. Of course, the true texture of Guinness comes down to the absolute last step: nailing the perfect pour.