What was your finished temp of the brisket, or did you just go by probing for tenderness?
Is your chamber temp gauge accurate?
The reason I ask about temps is that an 11lb brisket for 10 hours wouldn't be fully cooked, unless you have a rig with extremely high convective efficiency, meaning it is has optimal heat flow through the smoke chamber which allows for faster cooking at lower temps than the average smoker is capable of achieving. I'm thinking your chamber temp gauge is reading way too low, by maybe 60-70* or more, which would mean you cooked @ over 250*. This is highly possible, if the brisket was fully cooked in that short of a time period.
Smoking with a wood fired rig should give the deepest smoke penetration out of all other types of heating, and I get a nice smoke ring if I start out at lower temps and then bump to 225* or so with propane or charcoal fired rigs. The smoke ring, as we refer to it by, is actually initiated by the burning of fuels which create NO2 (nitrogen dioxide) in the cooking chamber, and therefore will not happen in electric smokers unless excessive amounts of smoke wood are used and are burning more rapidly than needed to produce smoke.
If I start out with higher temps, I do notice a slightly less pronounced smoke ring with less penetration, and this is pretty normal. As the meat cooks and the internal temp rises, the smoke reaction begins to taper off, and eventually ceases @ about 140* I/T, hence, lower start-up temps giving the most depth of smoke ring in uncured meats.
Eric