how come my brisket takes so long?

[jerseydrew]

everywhere i see that it should take roughly 1.5 hours per lb. this is my second time cooking a 4 lb flat. first one was 10 hours and this one has been on for 8 so far and is only at 172 degrees. i'm cooking at 225.

 

[tjohnson]

crank it up to 275°

 

[rdknb]

the 1.5 hour hardly ever works for me, as I do not foil.  As said about raise the temp.

 

[jerseydrew]

i have a butt in the smoker going all night i don't want to mess with the temp too much so i bumped it to 235. i might try something higher next time.