Rib Exterior Tough

Need some more details. The outside being tough usually is overcooked. Since you're steaming them (foil) they get done faster and I never have ribs take 5 hours unless they are Full Spares (not St. Louis)

I hate the X-X-X method because no one takes into account the weight of the rack of ribs.

How much did your rack weigh?

What kind of rib?

Tell us a little more about your process (in the foil) and after the foil)

Yes I agree, I usually never do 5 hours. I do adjust as needed to doneness. Usually 2 hours no foil, then butter, brown sugar meat side down in foil for as needed till doneness I'm looking for, then uncover and flip over, sauce and put it back in the smoker for about 30-60 minutes. Using Compart spares - 2.25/2.5 lbs per rack.

Assuming you do toothpick for tender...

I've found that foiling with a sugar component will produce the results you describe...more so with Spares vs backs.

My assumption is the brown sugar/honey/Agave caramelizes the out layer of meat do to higher temps resulting from the foiling process. That said, I've tasted ribs, which were foiled, that weren't chewy on the edges. Most of those were allowed to steam off when done, refoiled and held in a Cambro for 30-60 minutes +\-. Perhaps the resting period was a factor.

You didn't mention the inclusion of apple juice in the pouch. When I did pouch ribs, I added a cpl TBSP's of AJ. The absence of it would intensify the sugar caramelization

Yes I do toothpick, but I did not add AJ. They were vented, rewrapped and allowed to rest for about 30-45 minutes in 180 holding. Thinking the sugar may be the key.

Consider substituting Parkay for the Butter. Brown sugar & butter makes more of a crust.

Sorry, said butter, meant Parkay.