Does bark set in butcher paper?

I would unwrap it and let it ride. It still may not bark up if it turned into a paste.

I would think 325 will crisp it up. Just keep an eye on it so it doesn't get away from you.

That 's beaurty of BP you bark will still develop.

Never had a brisket go that long and not develop a decent bark. Also, staying at 165 for 6 hours seems odd too. How are you measuring temps in the cooker?

Were you spritzing the whole time? That will add a lot of time to your cook while the temp tries to recover.

Yes - paper lets a nice bark form.

My bark is usually starting to develop (not completely devoloped, but a very light crust) after about 6 hours

Butcher paper will allow the meat to breath while it slightly speeds up cooking time and keeps the nice firm bark you desire.

Some butcher papers are treated with a coating, some think it is merely a wax coating. The coating may not be wax, but could more likely be a thin polyethylene coating. Either way, wax or plastic coated papers are not really suited for cooking food in them. They are designed to seal the meat in a manner to prevent loss of moisture for short term storage and/or freezing.

The preferred butcher paper has no coating of any type and is thicker, denser, and heavier in weight. Uncoated butcher paper will allow the meat to breath while it speeds up cooking time and keeps that bark nice and firm.

Spritzing only adds moisture into what should become bark.

275 for 6 hours should have set the bark up nicely. I would try not spritzing the brisket. Let it ride for the 6 hours without opening the smoker. Wrap when the bark looks good regardless of temp, let it run naked until it sets the way you want, then wrap for the duration of the cook. Also, if the rub is very thick, it can hinder the bark especially if you are spritzing the meat.