When first learning how to smoke brisket, you'll likely find yourself at a point where you need to wrap the meat.
There are a number of different opinions on when it's best to wrap brisket. The ideas range from various internal temperatures, color changes on the meat, timed increments, and feel. In my opinion, a combination of these factors is best.
Personally I want at least 5-6 hours of smoke and a dark, mahogany-colored bark. Typically when those two things happen, the internal temperature has reached the point where the brisket is stalling (150-170F). The fat should also feel like you're pushing into a marshmallow and have a slight jiggle. All of these factors combined result in the best time to wrap.
Brisket is wrapped in order to combat a phenomenon called "evaporative cooling." Essentially, as the meat "sweats" it causes moisture to evaporate which cools the meat down.
You can equate this phenomenon to human physiology; Humans sweat in order to cool their body's down.
As the temperature of the cold meat continues to rise, the evaporation rate increases until the cooling effect essentially balances out the heat input.
The result is what's known as the brisket stall or plateau. Evaporative cooling occurs until all the moisture on the surface is gone.
The above is an important realization as most of the bark formation occurs after the start of the stall.
A lot of resources/people will tell you to wrap right at the start of this process - usually at a measured internal temperature of 150F - rather than during it.
In my opinion, their logic is flawed and you can output better brisket by waiting a bit longer.
Brisket will tend to stall at around 155 - 165F internally. During the stall the brisket may even drop in internal temperature.
For some reason, a lot of people will immediately wrap their brisket as soon as it reaches 150F. In my opinion, wrapping at this stage is ill informed.
For starters, the brisket flat and the brisket point will almost always probe at different temperatures. In most cases, the point will finish before the flat.
The pictures below were taken at the same time in two different parts of the brisket.
Brisket flat temperature probing 147.2F:
Brisket point temperature probing at 158.7F:
My best advice is to probe the thickest part of the flat and to not worry about the point - the point contains more fat and will probe tender much faster. Be sure to measure internal temperatures from this same area throughout the cook.
Once the brisket has remained in the stall for quite a while, it will start to develop an outer crust or "bark."
If you're going to wrap based on internal temperature, wait until the thickest part of the flat is at least 170F.
When smoking brisket, if you wrap too early, you risk ruining the bark or having a lack there of.
As the brisket continues to smoke, the rub will start setting up and the crust/bark will take on a red/mahogany color.
Here's a picture of brisket being put on my smoker at 11:34 am.
Here's a photo of the brisket at 1:41 pm.
Here's the brisket at 3:57 pm:
Here's the brisket at 4:27 pm:
The overall smoke time above is 5 hours.
Learning what to look for in terms of color-change is something you'll learn over time and it's hard to explain exactly what to look for. Essentially you want the exterior to be a deep, dark mahogany color.
There are a few issues with wrapping too early.
The first one has to do with not enough smoke. Depending on the material you use to wrap you can even prevent the infiltration of smoke.
For instance, if you opt to completely wrap in Aluminum foil (also called a Texas Crutch) you will prevent all smoke from penetrating the wrap since aluminum foil is non-porous.
The second has to do with the rub.
Aluminum foil is notorious for ruining bark. Since it's non-porous, the build up of moisture has to go somewhere which is on the brisket itself. If the bark hasn't set, it will simply wash away or turn mushy.
To avoid mushy bark, people will often use butcher paper as it's porous. With that said, the same issue applies as the amount of smoke penetration is essentially insignificant.
However, you can get away with wrapping earlier without entirely ruining the bark as the paper absorbs fat and moisture.
Using specific timed increments rarely makes sense when smoking meat. However, typically after 5-6 hours of smoking brisket, the meat has taken on enough wood smoke flavor.
At this point the bark has likely developed and your internal temperature has likely reached 165-170F.
This number is highly variable though and depends on the temperature you smoke at (I prefer 250F), the size of the brisket - especially if it's trimmed (8-12 lbs is a good size), even your smoker and it's design.
To reiterate: The wrap materials above will impede the penetration of smoke. Meaning, if you're smoking on a charcoal smoker, you should not be adding wood chunks after you wrap.
Technically at this point you're just using the smoker for heat/BTU output. You could even bring the wrapped brisket indoors and put it in your oven at 250F. Electricity is cheaper than charcoal and your brisket doesn't know the difference in heat source.
Granted, your house will smell like smoked brisket for a while. My personal preference is to use my Masterbuilt Electric Smoker to hold overnight.
The above brisket received 5 hours of post-oak wood smoke before being put into a tin-foil boat.
I typically will only start touching the rendered fat when the color has changed to look like the above.
Trying to explain what something feels like over the internet is fairly hard to do but the best description I can give is that the rendered fat will start to feel like a soft marshmallow and have a slight jiggle.
There are so many different opinions on this topic. Over the years I've tried the usual methods: aluminum foil, butcher paper, and no wrap.
For the past two years, my preference has been to do a tin-foil boat; I first saw this method done by Chud's BBQ - who is actually an Alumni of my Highschool - Bradley Robinson (talk about a small world).
In my opinion, it's truly the best way to get the benefits of aluminum foil - getting past a stall - while still maintaining the bark.
The method is as simple as placing the brisket fat-side up in the center of two sheets of aluminum foil. You then curl the foil up so that it creates a "boat" around the perimeter of the brisket.
When I first started smoking brisket I tried aluminum foil and quickly changed to butcher paper; I wasn't quite satisfied with either output. I then tried not wrapping and didn't enjoy waiting hours on end for the stall to pass.
The foil boat is a happy medium. You get great fat rendering, bark, and a cook that's faster than not wrapping.