Source: Dennis Flaherty (email@example.com), r.c.b., 5/4/95
Briess Black Malt may be used instead of Hugh Baird for an even more harsh and astringent flavor. If you substitute another brand of roasted barley, you may have to use less of it.
The oats are added right to the grist-- quick oats are already pre-gelatinized. An 18-oz canister will do, but much more will result in hazy beer due to the oil.
I refuse to doctor my stouts with bacterial contamination just because Guinness does.