How Long to Smoke a 12 lb Brisket Flat at 225°F
Smoke a 12 lb brisket flat for about 15h at 225°F, then rest 60 minutes. Pull at 203°F internal.
Last updated 2026-05-21 · By SmokerCookTime editorial team
Quick answer
A 12 lb brisket flat smoked at 225°F takes about 15h in the smoker, plus a 60-minute rest. Pull at 203°F internal temperature. Wrap in butcher paper at 165°F internal.
At a glance
- Smoker temp: 225°F
- Cook time: 15h (75 min per lb)
- Internal target: 203°F
- Wrap at: 165°F internal
- Rest: 60 minutes minimum
- Total time: 16h
Cook time at a glance
| Smoker temp | Approx cook time | Total with rest |
|---|---|---|
| 225°F | 15h | 16h |
| 250°F | 13h 30m | 14h 30m |
| 275°F | 12h 18m | 13h 18m |
Internal temperature target
Pull the brisket flat when the thickest part hits 203°F on a probe thermometer. Wrap at 165°F internal in butcher paper or foil.
Technique note
Wrap in butcher paper at 165°F internal to push through the stall. Rest in a dry cooler for the full hour.
Recommended pitmaster books
Franklin Barbecue: A Meat-Smoking Manifesto (Spiral Bound)
The bible of central Texas brisket. Aaron Franklin's full method — fire management, salt-and-pepper rub, the wrap, slicing. Spiral-bound so it stays flat at the smoker.
Franklin Smoke: Wood, Fire, Food (Spiral Bound)
Franklin's wood-pairing reference plus 70+ recipes beyond brisket. The best book for understanding how different woods change the cook.
Smokin' with Myron Mixon (Spiral Bound)
Competition recipes from a four-time world BBQ champion. Brisket, ribs, pork shoulder, chicken — Mixon's exact rubs and injections. Spiral-bound and grease-resistant.
Yellowstone: The Official Dutton Ranch Family Cookbook (Spiral Bound)
Chuckwagon-style cooking inspired by the Yellowstone ranch — smoked meats, cast-iron classics, outdoor cooking. The crowd-pleaser of the four.
Frequently asked
How long does it take to smoke a 12 lb Brisket Flat at 225°F?
About 15h of smoke time, plus a 60-minute rest. Total 16h. Cooking time is an estimate — pull at 203°F internal.
What internal temperature should a Brisket Flat reach?
Pull at 203°F internal temperature. Use a probe thermometer; do not rely on time alone.
Should I wrap a Brisket Flat during the smoke?
Yes — wrap at 165°F internal in butcher paper or foil to push through the stall.
How long should a Brisket Flat rest after smoking?
Rest for at least 60 minutes — this is non-negotiable for redistributing juices and finishing carryover cooking.