A succulent, glazed ham is the centerpiece of many celebrations, from Easter brunches to Christmas dinners. However, because most hams purchased at the grocery store are already “city-hams”—meaning they are precooked or smoked—the challenge isn’t actually cooking the meat, but reheating it without drying it out. Knowing exactly how long cooked ham in oven should stay is the difference between a tender, juicy slice and a salty piece of leather.
In this comprehensive guide, we will break down the timing for various types of ham, the ideal internal temperatures to reach, and the techniques that ensure your holiday roast remains the star of the show.
Understanding Your Ham Type Before You Heat
Before you can calculate your timing, you must identify exactly what kind of ham you have. Most “cooked” hams fall into two categories: bone-in and boneless.
Bone-In Cooked Ham
Bone-in hams are generally considered more flavorful because the bone helps conduct heat and adds depth to the meat’s profile. These take slightly longer to heat through because the bone acts as an insulator initially.
Boneless Cooked Ham
These are pressed into a specific shape for easy slicing. Because there is no bone to navigate, heat penetrates the center more quickly. However, boneless hams are more prone to drying out if left in the oven even ten minutes too long.
Spiral-Sliced vs. Whole
Spiral-sliced hams are pre-cut by the manufacturer. While convenient, they are the most delicate. The “how long” factor is critical here because the heat can easily slip between the slices, evaporating moisture and leaving the edges tough.
General Rules for Timing and Temperature
The goal for a precooked ham is to reach an internal temperature of 140°F. Since the meat is already safe to eat, you are simply warming it to an appetizing level.
The Low and Slow Method
To maintain moisture, it is best to keep your oven at a moderate temperature. Most experts recommend setting your oven to 325°F. At this temperature, a whole, bone-in cooked ham typically requires 15 to 18 minutes per pound.
Calculating by Weight
If you have a half-ham (usually 7 to 10 pounds), the timing shifts slightly. You should estimate about 18 to 24 minutes per pound. For a smaller boneless ham, you can usually expect 10 to 15 minutes per pound.
Step-by-Step Instructions for Reheating
To get the best results, you shouldn’t just toss the ham in a pan and hope for the best. Follow these steps to ensure the timing yields a perfect result.
Preparation and Wrapping
Remove the ham from the refrigerator about 30 to 60 minutes before you plan to put it in the oven. Taking the chill off the meat helps it heat more evenly. Wrap the ham tightly in heavy-duty aluminum foil. This is the most important step in the reheating process; it traps the steam and prevents the exterior from becoming “jerky-like” while the center warms up.
Adding Moisture
Place the wrapped ham in a roasting pan. Many chefs recommend adding about half a cup of water, apple cider, or white wine to the bottom of the pan before covering the whole thing with a lid or a secondary layer of foil. This creates a small steam chamber.
Monitoring the Internal Temperature
About 30 minutes before your calculated time is up, begin checking the internal temperature with a meat thermometer. Insert it into the thickest part of the meat, making sure not to touch the bone. Once it hits 135°F, it is time for the final stage: the glaze.
The Glazing Phase: Adding 15 Minutes
The glaze is what gives a ham its beautiful mahogany sheen and sweet-savory crust. However, because glazes contain high amounts of sugar, they will burn if they are in the oven for the entire reheating process.
When to Glaze
Increase the oven temperature to 400°F. Carefully remove the ham from the oven and peel back the foil. Brush your glaze (usually a mix of brown sugar, honey, mustard, or cloves) generously over the surface. Return the ham to the oven, uncovered.
The Final Blast
Bake for an additional 10 to 15 minutes. Watch it closely; you want the sugar to bubble and caramelize but not turn black. This final step brings the internal temperature from 135°F to the target of 140°F.
Factors That Influence How Long Your Ham Takes
Not every oven is calibrated the same way, and not every ham is the same shape. Several variables can alter your timing by 20 minutes or more.
Oven Calibration
If your oven runs hot, you may find your ham reaches 140°F much faster than the “per pound” rule suggests. Conversely, if you are also baking side dishes like scalloped potatoes or green bean casserole at the same time, the oven temperature may drop due to the overcrowding, requiring more time for the ham.
The Shape of the Meat
A long, thin ham will heat much faster than a round, bulbous “football” shaped ham. The closer the center of the meat is to the surface, the faster the heat will reach it.
Spiral Slicing Risks
If your ham is spiral-sliced, reduce your estimated time by about 2 minutes per pound. Because the slices are already separated, the heat doesn’t have to work as hard to get to the middle. This is the ham variety that is most often overcooked and ruined.
Rest Time: The Final Step
Once the ham reaches 140°F and the glaze is set, remove it from the oven. This is where many home cooks go wrong—they slice it immediately.
Allow the ham to rest, tented loosely with foil, for at least 15 to 20 minutes. During this time, the juices redistribute throughout the meat. If you cut it immediately, the juices will run out onto the cutting board, leaving the meat dry. Furthermore, residual heat will carry the temperature up a few more degrees, ensuring it is piping hot when it hits the plate.
Summary Table for Quick Reference
To make your holiday planning easier, here is a breakdown of estimated times for a 325°F oven:
- For a Bone-in Whole Ham (12 to 16 lbs): 15 to 18 minutes per pound.
- For a Bone-in Half Ham (7 to 9 lbs): 18 to 24 minutes per pound.
- For a Boneless Ham (5 to 8 lbs): 12 to 15 minutes per pound.
- For a Spiral-Sliced Ham (7 to 9 lbs): 10 to 12 minutes per pound.
Always remember that these are estimates. Your meat thermometer is your only true guide to success.
Frequently Asked Questions
Can I reheat a cooked ham at a higher temperature to save time?
It is not recommended to reheat a cooked ham at temperatures higher than 325°F for the duration of the process. High heat causes the muscle fibers to contract and squeeze out moisture, resulting in a tough texture. It is better to start early at a lower temperature and let it warm gradually.
What if my ham is labeled “Ready to Cook” instead of “Fully Cook”?
This is a critical distinction. A “Ready to Cook” ham must be cooked to an internal temperature of 160°F to be safe for consumption. This will take significantly longer—usually 20 to 25 minutes per pound at 325°F. Always check the packaging carefully to ensure you aren’t just warming up raw pork.
Should I leave the ham in the plastic mesh while heating?
No, you should remove all plastic packaging, including any mesh or “socks” the ham may have come in, before putting it in the oven. However, if there is a small plastic disc covering the bone end, make sure to pop that off as well, as it can melt or cause odors.
How do I prevent a spiral ham from drying out?
The best way to protect a spiral ham is to place it cut-side down in the roasting pan. This protects the vulnerable slices from direct exposure to the air. Additionally, wrapping it very tightly in foil and adding a liquid (like pineapple juice or water) to the pan creates a moist environment that saves the slices.
Is it safe to eat a “Fully Cooked” ham cold?
Yes, a ham labeled “Fully Cooked” is safe to eat straight out of the package. Reheating is purely for flavor and preference. If you are serving a ham for a summer picnic or as part of a sandwich platter, you don’t need to put it in the oven at all, which saves you the trouble of calculating timing entirely.