How Long to Smoke a Brisket at 250F {Budget for an Extra Two Hours!}

When you are planning out your barbecue session it can be tricky figuring out how long to smoke a brisket.  There are a lot of variables that go into this equation but the biggest one if you are wrapping the brisket and if so, are you using aluminum foil or butcher paper. 

A general guideline is, if you are cooking “Low and Slow” at 250F, then a 12 pound brisket will take between 10-15 hours depending upon if you choose to wrap it in butcher paper, aluminum foil or leave it unwrapped.  

Use the chart below to estimate cook times for different sized briskets.

Keep reading and we will cover the limitations of these guidelines PLUS why you need to budget an extra two hours.

Limitations of Time Guidelines for Smoking Briskets at 250F

The guidelines given above are for a full sized packer brisket.  The guidelines start to break down when you are smoking smaller pieces like a 3.5 pound section of brisket flat.

A small section of brisket, say 3-4 pounds, will still take at least 5 hours to cook and that is if you are wrapping in foil after it has smoked for at least 2 hours.  The reason the time per pound guidelines break down for smaller cuts is that the real variable is not the weight of the brisket.  The variable that actually matters is the thickness of the meat.

In full sized briskets there is usually a direct correlation between weight and thickness.  For example, a 12 pound full packer brisket will be around 1.5 inches thick in the flat while a 17 pound brisket might be around 2.5 inches thick.  It makes sense that the thicker brisket is going to take longer to cook.

However, if we sliced off a four pound section of the flat from the 17 pound brisket it is still going to be about 2.5 inches thick and need a long time to cook.

Brisket is a tough piece of meat and you are going to need a lot of time to get it tender.  The chefs at Cook’s Illustrated explain that brisket takes so long to get tender because the meat has a high level of insoluble collagen.  The insoluble collagen found in brisket takes much longer to break down than the soluble collagen found in other braising cuts.

A thick, four pound section of brisket is still going to have plenty of insoluble collagen.

Another factor that causes deviations from the time/temperature guides is the nature of the beef itself.  The fat content between a Select, Choice and Prime brisket are extremely different and this will impact cook times.  In general, the higher the quality of the beef the quicker it will cook.  This is especially true when you bump up in quality and cook a Wagyu brisket.

Why Does Wrapping a Brisket at 250F Speed Up The Cook?

The use of butcher paper and aluminum foil serves two purposes.  The first purpose is to protect the brisket from taking on additional smoke that would impact the flavor and appearance of the bark.

The second purpose is that wrapping the brisket helps it push through “The Stall”.  The Stall is the point in which the internal temperature of the brisket will not budge for a couple of hours and is caused by evaporative cooling.  The team at Texas A&M University did a demonstration of cooking briskets either wrapped or unwrapped side by side and showed how wrapping helps the brisket push through the stall faster.  Here is a link to the graphical data as well as the original article.

While wrapping the brisket in either butcher paper or aluminum foil helps the brisket push through the stall there are trade offs between the two materials.  When you wrap with aluminum foil for get a tighter seal which really speeds the cook up.  It is commonly held that a brisket wrapped in butcher paper will have a better bark than one wrapped in aluminum foil as the butcher paper lets he brisket “breathe” while the aluminum foil can cause the bark to get soggy and “washed out”.

How Do You Know When The Brisket Smoked at 250F Is Done?

The biggest mistake people make when smoking a brisket is they take it off the pit before it is finished.  An undercooked brisket is going to be tough, dry and not a fun eating experience.

There are two ways to tell when a brisket is finished.  The first in that the internal temperature of the flat will be between 200F-210F.  The real test for doneness is when you insert your thermometer into the flat it simply slides through the meat.  You don’t even need a thermometer to do this test.  You can take a wooden skewer and as soon as it is able to slide through the point like it is going through warm butter then you have a finished brisket.

One way people mess up on determining doneness is by measuring the temperature of the point instead of the flat.  A brisket is composed of two muscles, the fatty “point” and the lean “flat”.  Because the point is so fatty it will ALWAYS finish cooking before the flat.  The point will get to 205F and be probe tender while the flat might only be at 190F and is still tough.

The work around is that once the point is fished you can separate it from the flat.  You can wrap the point in foil to keep it warm and return the flat to the pit to finish cooking.  Alternatively, now is the time to cut the finished point into cubes, apply sauce and a little more rub, then put back on the smoker to make burnt ends.  By the time the burnt ends are ready the flat should be as well!

The Last Step (Extra Time After Smoking at 250F)

If you can plan ahead and have a few extra hours to spare then you can follow the lead of the competition brisket masters and take your brisket to a whole other level.

One of the best brisket cooks in the country is Myron Mixon. Myron has stated multiple times that the most important factor in making an awesome brisket is to start with amazing meat (he cooks American Wagyu).  Myron says the second most important factor is to wrap the finished brisket in foil, place in an insulated cooler, and allow it to rest for 2-4 hours before slicing.  Multiple competition pitmasters have said the exact same thing.  By the way, here is the link to Myron’s complete brisket recipe.

I know that after smoking a brisket for 12 hours that you just want to cut into it and start devouring the slices but, if you have the time and patience, letting it rest in a warm location for a few hours is going to make a HUGE difference.