Although not required, it can be easier to chop up the bacon if you put it in the freezer for 20-30 minutes.
Although using stock for the liquid will enhance the dish, I've used water with this recipe before and it still tastes great.
If you are using store-bought stock that's high in sodium you won't need to add as much salt as I did.
Using 3 chipotles creates some real heat! For a milder version use only 1-2 chipotles. Also note that in a pinch you can substitute fresh jalapenos for the chipotles.
I typically use half of the batch to make a bean puree.