“Each 12-ounce serving of Dunkin’ Coffee Porter has only 2.7 mg of caffeine ,” Harpoon’s CEO and cofounder Dan Kenary told me. Beers that cold-infuse coffee could have significant caffeine levels since they’re mimicking the process of making cold brew.
When alcohol is mixed with caffeine, the caffeine can mask the depressant effects of alcohol, making drinkers feel more alert than they would otherwise. As a result, they may drink more alcohol and become more impaired than they realize, increasing the risk of alcohol-attributable harms.
There are two ways to get coffee flavors in your beer — with coffee or without. Most stouts and porters are brewed with highly-toasted barley malts, chocolate malts and black patent malts for flavor and creaminess. It is the deep roasting of these grains that give the darker beers hints of coffee -like flavors.
According to the Beer Judge Certification Program a Stout is defined as “a very dark, roasty, bitter, creamy ale,” while a Porter is described as “a substantial, malty dark ale with a complex and flavourful character.” Basically a Stout has roasted malts and associated flavours, whereas a Porter does not.”