Feeling Oats
Oatmeal is a gelatinized form of oats, in which the raw grain is cooked and then flattened, rendering the starches suitable for breakdown by the amylase enzymes in barley. As a brewing ingredient, oatmeal is one that is used sparingly, but has a marked desirable influence on the finished product. The high protein content is coveted because of the influence it has on the head and head-retention. Protein creates a thick, mousse-like foam that is less likely to disintegrate. As protein is unfermentable, it also lends a viscous impression.
Protein is also a potential culprit in a mash in that it tends to form a gluey mass that prevents proper drainage. The lack of husk exacerbates that situation.
The higher oil content of oats provides a silky-smooth, almost slick mouthfeel, and one that acts synergistically with the excess protein to produce a full-bodied, rich brew that is slightly sweet, but not cloying. Oatmeal is usually used at less than 10% of the grist, with 5% or so being about the norm.
Oatmeal stouts are more substantial all around than Irish dry stouts, though not terribly so, with slightly less roast character. They are just as dark, with chocolate and deep crystal malts often making up for the lack of roast in color, with the added benefit of more complexity. They might almost be thought of as a light version of Imperial stout.
The hop rate is fairly modest, with the focus on bittering rather than aroma. American brewers might buck this trend a little bit, but in general, the emphasis is on the multifarious malt bill and richness therein. As with most English/American sibling beers, each will take on the overall character of their respective homeland. Alcohol by volume is between 5 and 6.5% in the finished beer.
Oatmeal stouts offer something different for stout-lovers. They are neither one-dimensional nor overwhelming, and it would be hard to find a better constituent to temper the traditional full-roast flavor than oatmeal. They are contemplative enough to consume as a nightcap, and modest enough to session over. With winter looming, they might be the perfect option for those cold evenings.
