Toasting dried chiles until they smell awake
Ok, this is the part of the marinade where people either get it right away or they burn a whole batch and have to start over. I've done both. We're gonna aim for the first one.
Dried chiles are where most of your al pastor flavor actually lives, more than the pineapple, more than the spice mix. But dried chiles are also just sitting there dead until you wake them up with heat. That's the toasting step. You're not cooking them, you're not browning them like meat. You're waking them up.
What you need
Guajillos and anchos, mostly. Maybe a couple arbols if you want heat, but go light there, they're a different animal. Stem them and shake out the seeds first — tear the top off, crack it open, dump the seeds in the trash, not down your sink. A dry cast iron pan or a comal if you have one. No oil. This is a dry toast.
The actual technique
Pan on medium, no oil, let it heat up while you're stemming chiles so you're not standing around waiting on it — this is that mise en place thing again, get everything ready before the flame's doing anything.
Lay the chiles flat in the pan, skin side down first. You want them making full contact. Give it about 20 to 30 seconds, then flip. Another 20 to 30 on the other side. That's it. That's the whole toast.
Here's what you're watching for: the chile should puff up slightly, get a little shiny and pliable, and — this is the real test — smell like something. Toasty, a little sweet, almost like raisins or dried fruit. That smell is the whole point. When it hits your nose and you think "oh, that's awake now," you're done. Pull it.
If you smell anything acrid or sharp, you've gone too far. That's burnt chile, and burnt chile is bitter in a way you cannot fix later. Not "spicy" bitter. Ashtray bitter. It'll wreck the whole batch of marinade because a little burnt chile ruins a lot of good ones.
The story behind this one
I learned this exact phrase — toast em till they smell awake — from the dad in my mission branch in Kyiv. He'd do this whole spread out of an apartment kitchen that had no business producing al pastor, and he showed me the chile step maybe four times before I asked if I could try it myself.
First time I did it solo, no supervision, I got cocky and let them go too long because I was talking to somebody and lost track. Burned the whole batch to bitter black. I was so embarrassed I did a DI run that same day for a new pan because I didn't even want to look at the one I'd scorched. Kept the lesson though. Smell, not time. Your nose knows before your eyes do.
After the toast
Once they're toasted, soak them in hot water for 15 to 20 minutes until soft and pliable. That's what makes them blend into a smooth marinade instead of leaving little bits of tough skin in there. Don't skip the soak, and don't use boiling water straight off the stove, hot tap water or just-off-boil is fine.
Here's the thing on seasoning too, while we're at it — people think the marinade is done once the chiles and spices are blended, but you still gotta salt it and taste it like it's its own dish. A flat marinade almost always means it needed more salt, not more of some other ingredient. Taste it plain off a spoon before it ever touches the pork.
A word on batching this
I'll be honest with you about something. I once made a giant batch of this marinade thinking I'd freeze half and have "meal prep" for the next month, real proud of myself for planning ahead. Found it in the deep freeze eight months later, freezer burned, totally unusable. The planning guy in me wrote a check the follow-through guy never cashed.
So make what you need for this cook. If you want extra, freeze it in a labeled bag with a date on it, and actually use it inside a month. Don't be me.
Before next time
Grab a bag of dried guajillos and anchos from Macey's or wherever you shop — check the Mexican foods aisle, they're usually cheap and sold loose or in small bags. Have them ready to stem and toast when we meet next.