Of course, what everyone talks about at Al's is the Italian beef, and rightly so: it's a spectacular sandwich that deserves accolades (and has received them on Serious Eats already). But the result of all that praise is often that their excellent Italian sausage sandwich—served, just like the beef, with sweet or hot peppers on a chewy roll seemingly designed to soak up juices without losing its structural integrity—can be overlooked.
Which is a shame, because it's excellent, even if it looks rather unkempt (okay, messy). And just like the Italian beef, which is best eaten after being dunked in the delicious beefy juices, the sausage juices play an integral role in this sandwich—so long as you ask for them. (I've had the Al's Italian sausage a few times both from their original Taylor Street location and from their increasing number of franchises, and the only time it wasn't good was when the juices were left out, and it was dry).
But first, about the sausage: it's cooked on long skewers over a long, skinny row of charcoal, giving it an especially smoky flavor and charred casing, evenly cooked. Inside, it's flavored classic Italian, with whole fennel seeds and bits of chile flake.
After cooking, Al's keeps the cooked sausage in a tray, ready to be scooped into a sandwich. And it's that tray where the accumulated juices and fat—what the counter guy often calls "the gravy"—comes to rest. It's a porky, spicy soup that's just asking to be spooned on top of the sandwich. And it should be.
And with both sweet and hot peppers (the way to go is to ask for half and half), that crisp sausage, the chewy bread and all that "gravy," you've got a messy, but remarkably delicious sandwich to contend with.