Which flavor is predominant in Irish Stout due to the use of unmalted roasted barley?

In Irish stout, the predominant flavor arising from the use of unmalted roasted barley is indeed acrid coffee. Unmalted roasted barley contributes a significant roasted character that is often described as dark, rich, and sometimes bitter, akin to the flavors found in coffee. The roasting process used for this barley amplifies these characteristics, leading to a coffee-like aroma and flavor profile, which is quintessential to the style of Irish stout.

The incorporation of unmalted roasted barley distinguishes Irish stouts from other dark beers, enhancing their complexity with deep, roasted notes without sweetness, as seen with other malts. The result is a beer with a dry finish, showcasing the roasted barley's acrid and intense coffee flavors that give Irish stouts their signature profile.

Other flavor options such as fruity citrus or creamy vanilla do not typically arise from roasted barley in Irish stout, while bittersweet chocolate may be a characteristic of stouts with chocolate malt or roasted malt, rather than being solely attributed to the unmalted roasted barley. This makes acrid coffee the most accurate representation of the flavor brought by this key ingredient.