Grill Pork Loin: 15-20 Min Per Side to 145°F

Grill pork loin for 15-20 minutes per side over medium heat (350–400°F) until it reaches 145°F internally, then rest 3 minutes. This precise timing ensures safe, juicy results without drying out the meat – the critical sweet spot every griller needs to know.

Your Complete Guide to Perfectly Grilled Pork Loin

Nothing beats the smoky flavor of perfectly grilled pork loin, but timing mistakes turn this premium cut into dry disappointment. After decades of testing variables from grill type to meat thickness, we've pinpointed the exact window for foolproof results. Forget guessing games – this guide delivers science-backed timing you can trust.

Why Timing Matters: Safety Meets Perfection

Undercooked pork risks foodborne illness, while overcooked meat becomes tough and dry. The USDA’s revised safety standards confirm pork is safe at 145°F internal temperature with a 3-minute rest. This modern guideline replaced outdated 160°F recommendations after extensive research showed lower temperatures eliminate pathogens while preserving moisture.

Pork Loin Thickness	Grill Temp	Approx. Cooking Time	Target Internal Temp
1.5 inches	350–400°F	15–18 min per side	140°F (will rise to 145°F)
2 inches	350–400°F	18–22 min per side	140°F (will rise to 145°F)
2.5+ inches	325–375°F	22–25 min per side	140°F (will rise to 145°F)

Pre-Grill Prep: Setting Up for Success

Temperature equilibrium is non-negotiable. Pull pork loin from the refrigerator 45 minutes before grilling. Cold meat cooks unevenly, creating gray bands near the surface while the center remains underdone. Pat the roast completely dry with paper towels – moisture is the enemy of proper searing. For best results, apply a light coating of oil and your preferred rub 30 minutes pre-grill to allow flavors to penetrate without drawing out moisture.

The Grilling Process: Your Step-by-Step Timeline

Phase 1: Grill Setup (5 Minutes)

Preheat your grill to medium (350–400°F). For charcoal, arrange coals for two-zone cooking. For gas, light only half the burners. This creates crucial indirect heat zones for finishing if flare-ups occur.

Phase 2: Searing (8–10 Minutes)

Place pork loin directly over heat. Sear undisturbed for 4–5 minutes per side until deep golden-brown. Resist the urge to move it – proper searing requires contact time. If flare-ups happen, temporarily move to indirect zone.

Phase 3: Precision Cooking (10–15 Minutes)

Move pork loin to indirect heat. Cover the grill and cook until internal temperature reaches 140°F. This is where most mistakes happen: rely solely on a digital thermometer, not time estimates. Insert it horizontally into the thickest part, avoiding bone or fat.

Phase 4: The Critical Rest (3 Minutes)

Transfer pork loin to a cutting board, tent loosely with foil, and rest for exactly 3 minutes. This allows juices to redistribute – skipping this step causes 20% moisture loss when slicing. The internal temperature will rise 3–5°F during rest, hitting the safe 145°F mark.

Avoiding Common Timing Pitfalls

Grill temperature fluctuations dramatically impact cooking time. Windy conditions or frequent lid-lifting can extend grilling by 25%. Always use a grill thermometer – built-in hood thermometers are notoriously inaccurate. For thicker cuts (over 2 inches), reduce heat to 325°F after searing to prevent exterior burning before the center cooks through. Never press down on the meat with your spatula; this squeezes out precious juices and accelerates drying.

When Thermometers Aren't Available: Visual Cues

While a thermometer is essential for food safety, these visual indicators provide secondary confirmation:
• Firm-but-yielding texture when pressed (like the base of your thumb)
• Clear juices (not pink) when pierced deeply
• Internal color transition from pink to pale tan
Note: Color alone is unreliable – some marinades or rubs affect appearance. Always verify with temperature.

Pro Tips for Consistent Results

For restaurant-quality results, try these chef-tested techniques:
• Reverse sear method: Cook indirectly at 275°F until 130°F, then sear for 90 seconds per side
• Brine for insurance: Soak in 4 cups water + ¼ cup salt + 2 tbsp sugar for 1–4 hours to boost moisture retention
• Thermometer placement: Insert probe horizontally through the side for most accurate core reading
• Wind mitigation: Position grill perpendicular to wind direction to maintain stable temperatures

FAQs: Your Timing Questions Answered

Can I cook pork loin faster at higher heat?

No. High heat (above 450°F) creates a tough exterior before the center reaches safe temperature. The 350–400°F range ensures even cooking without burning.

What if my pork loin is done early but not at 145°F?

Return it to indirect heat immediately. Remove only when thermometer confirms 145°F after resting. Early removal risks trichinosis from undercooked pork.

How does grill type affect cooking time?

Charcoal grills typically cook 5–8 minutes faster than gas at equivalent temperatures due to radiant heat. Pellet grills add 3–5 minutes because of lower heat density. Always verify with a thermometer.

Why rest for exactly 3 minutes?

USDA research shows 3 minutes allows muscle fibers to reabsorb juices without overcooking. Shorter rests cause moisture loss; longer rests let carryover cooking exceed 145°F.