What is a stout?  Come on in and see.  Stout is a stout version of porter.  Essentially, porters had more roasted barley or black patent malts (and other dark grains) added to them and began to be called stout porters.  Eventually, “porter” dropped off the name, and a style was born.  Like porter, stout is an ale.

Just to let the reader know, there is some argument among us real nerds about whether this or that robust porter is, in fact, a stout.  I only mention this to say that there is some room for interpretation when it comes to whether or not something is a stout.  For me, it has always been a simplistic bifurcation that has helped make the distinction between porter and stout; namely, stouts have black patent malts or roasted barley, which make them darker, more robust, and more coffee-like/chocolate-like than porters.  As you might have guessed, color has something to do with whether or not a beer could be considered a stout.  Can’t we all see past this color thing?  On a serious note, stouts tend to be dark, dark brown to darker than midnight black.

I mentioned above that stout is an ale, not a lager.  There are black lagers, but they are not technically stouts for various reasons.  The above links will clarify further, but black lagers use lager yeast and tend not to use some of the black patent and roasted barley that stouts do.  The biggest factor is certainly the yeast strain.

Now that we have a little more clarification about stouts, what types of stout are there?  The possibilities are endless.  There are stouts out there that literally use oysters, chicory, coconut and a variety of other additions.  Let me just give a few typical styles.

Dry Irish Stout:  Guinness, Murphy’s, and numerous others fit into this category.  Dry Irish Stouts tend to be lower in alcohol and, as the name implies, drier.  Grain types, level of attenuation (the amount of sugar that is fermented), and water type play major roles in the perceived dryness of the style.

Milk Stout:  This type of stout does not actually have milk in it.  Technically, it uses lactose, which is milk sugar.  Since this type of sugar is not fermentable, it comes through as sweetness, which is also why you will often see this termed a Sweet Stout and Cream Stout.  Mackison’s is the most commonly known version (I think they have the original patent on the style name).  A good U.S. version is Left Hand’s Milk Stout.

Imperial/Russian Imperial Stout:  Most often, this is a big, bold, heavier stout.  There are versions that are less thick and cloying, but the dominant type seems to be the heavier and thicker varieties.  These stouts have higher alcohol, as high as 18% or so, often higher hop levels, and are just bigger beers.  Even the more restrained versions such as Nils Oscar and Samuel Smith’s are comparatively big against some other stouts.  American domestic versions tend to be beastly varieties.

Oatmeal Stout:  As you might have guess, this version of stout includes rolled, steel cut, or flaked oats in its production.  Lactose and other sweetness are optional additions.  These stouts tend to be big on flavor and have a definite oatmeal quality in taste.  A real treat.  Samuel Smith’s is the most common version, while there are many U.S. versions that have come out in recent history.

Chocolate Stout and Coffee Stout: Both of these varieties rely on the addition of extra coffee or chocolate. As I mentioned above, stouts already have these tones, which the brewer chooses to make more emphatic by adding those actual flavors.  Additions can be mild to extreme.  Coffee makes an impact in relatively small volumes, while chocolate takes a substantial amount to be discerned.

Barreled Stout: Recently, more and more brewers are aging/simulating aging their beers in barrels. Including wood chips soaked in alcohol or using actual barrels are two increasingly common occurrences in the brewing world.  Bourbon, sherry, wine and numerous other barrels are used, but bourbon seems to be the most common.  The flavors and alcohol associated with the wood in the barrels are imparted to the beer. Depending on the length of aging, the flavors can be mild to extreme.  Goose Island’s Bourbon County Stout is a  good example (par excellence, in my opinion) of the stronger versions.

Other stout varieties could be recalled and cited, but most are varieties of the ones mentioned above.