The centerpiece of a holiday feast or a Sunday dinner is often a beautiful, glazed ham. However, because most hams purchased at the grocery store are already fully cooked or cured, the challenge isn’t actually cooking the meat—it’s reheating it without turning it into a dry, salty brick. Learning how to heat up a ham in the oven requires a delicate balance of moisture control, temperature management, and timing. Whether you are working with a massive bone-in spiral ham or a smaller boneless variety, the goal is a juicy, tender interior with a sticky, caramelized crust.
Understanding Your Ham Before You Start
Before you even preheat your oven, you need to know exactly what kind of ham you have sitting in your refrigerator. Most hams sold in modern supermarkets are labeled as “fully cooked,” “precooked,” or “city hams.” These have been brined and often smoked, meaning they are technically safe to eat straight out of the package. Your job is simply to bring them up to a palatable serving temperature.
If you happen to have a “fresh ham,” you are dealing with raw pork that requires full cooking to an internal temperature of 145°F followed by a rest. Conversely, a “country ham” is a dry-cured, shelf-stable product that is incredibly salty and usually requires soaking in water for 24 hours before it even touches an oven. For the purposes of this guide, we will focus on the most common variety: the fully cooked city ham.
Preparing the Ham for the Oven
Preparation is the secret to moisture. If you take a ham out of the plastic and toss it onto a baking sheet, the oven’s dry air will wick away the juices.
Room Temperature Transition
For the best results, take the ham out of the refrigerator about 1 to 2 hours before you plan to heat it. Bringing the meat closer to room temperature ensures that the center heats up more quickly, preventing the outer layers from overcooking while you wait for the middle to get warm.
Choosing the Right Pan
You need a sturdy roasting pan or a large 9×13-inch baking dish. The pan should have sides deep enough to hold liquid and the ham’s natural drippings without spilling. If you have a roasting rack, use it. Elevating the ham allows the heat to circulate evenly around the bottom, preventing the underside from becoming soggy.
The Secret to Moisture: Liquid and Foil
A ham is essentially a large muscle, and heat is its enemy when it comes to hydration. To fight the drying effects of the oven, you must create a steamy environment.
Adding Liquid to the Pan
Add about a half-inch of liquid to the bottom of your roasting pan. Plain water works fine, but you can add layers of flavor by using apple cider, orange juice, pineapple juice, or even a splash of white wine. As the oven heats up, this liquid will evaporate, creating a humid “sauna” for the meat.
The Double-Wrap Method
Tightly wrap the ham itself in heavy-duty aluminum foil. If you are using a roasting pan, you can also cover the entire pan tightly with foil. The goal is to create an airtight seal. This traps the steam against the meat, forcing moisture back into the fibers as the temperature rises.
Setting the Correct Oven Temperature
When it comes to reheating a precooked ham, low and slow is the golden rule. You are not trying to sear the meat; you are gently nudging it to a serving temperature.
Set your oven to 325°F. Some chefs prefer an even lower 275°F or 300°F if they have plenty of time, but 325°F provides a good balance between efficiency and quality. High temperatures, such as 400°F, will cause the proteins to contract and squeeze out all the delicious juices, leaving you with a rubbery texture.
Calculating Heating Time
The amount of time your ham spends in the oven depends entirely on its weight and whether it is bone-in or boneless.
Bone-In Ham Timing
A whole or half bone-in ham usually requires about 15 to 18 minutes per pound. For example, a 10-pound ham will take roughly 2.5 to 3 hours to heat through. The bone acts as a conductor of heat, but it also adds mass that takes time to warm up.
Spiral Sliced Ham Timing
Spiral hams are incredibly popular because they are easy to serve, but they are the most prone to drying out because the slices allow heat to penetrate the interior more quickly. These usually require less time, often 10 to 12 minutes per pound. Because of the slices, it is even more critical to keep these hams tightly wrapped in foil.
Checking for Doneness
The only way to be 100% sure your ham is ready is to use a meat thermometer. You are looking for an internal temperature of 140°F. Insert the thermometer into the thickest part of the meat, making sure not to touch the bone, as the bone will give a falsely high reading.
The Art of Glazing
A ham isn’t complete without a glaze. Whether it’s a classic brown sugar and mustard rub or a honey-pineapple glaze, the timing of the application is vital.
Most glazes contain high amounts of sugar. If you put the glaze on at the beginning of the heating process, the sugar will burn and turn bitter long before the ham is warm. Instead, wait until the ham has reached an internal temperature of about 130°F.
Remove the ham from the oven and increase the oven temperature to 400°F. Carefully peel back the foil—watch out for the steam!—and brush the glaze generously over the entire surface. Return the ham to the oven, uncovered, for 10 to 15 minutes. This high-heat blast will caramelize the sugars, creating that iconic glossy, dark crust. You can even baste it a second time halfway through this final window for an extra thick coating.
Resting the Ham Before Carving
Once the ham reaches 140°F and the glaze is perfectly tacky, remove it from the oven. This is the most underrated step: let the ham rest.
Transfer the ham to a carving board and tent it loosely with foil. Let it sit for at least 15 to 20 minutes. During this time, the muscle fibers relax and reabsorb the juices. If you cut into it immediately, the moisture will run out onto the board, leaving the meat dry. Resting ensures every slice is as succulent as the first.
Storing and Using Leftovers
If you find yourself with an abundance of ham after the meal, wrap the leftovers tightly in plastic wrap or aluminum foil and refrigerate within two hours. Ham stays fresh in the fridge for 3 to 5 days. For longer storage, you can freeze ham for up to 2 months.
Leftover ham is incredibly versatile. Beyond the standard sandwich, consider dicing it for omelets, adding it to a creamy split pea soup, or tossing it into a carbonara pasta. The bone itself should never be thrown away; it is a flavor powerhouse for stocks and bean stews.
Common Mistakes to Avoid
One common error is overcooking. Remember, you aren’t “cooking” the ham; you are “warming” it. Every degree over 140°F is pulling moisture out of the meat.
Another mistake is forgetting to score the ham. If you have a ham that isn’t spiral-sliced, use a sharp knife to cut a diamond pattern into the fat cap about a quarter-inch deep. This allows the glaze to penetrate the meat rather than just sliding off the surface.
Finally, don’t skimp on the foil. If the foil rips, replace it. A small hole can let out enough steam to significantly dry out the exterior of the ham.
Frequently Asked Questions
- Can I heat up a ham in a slow cooker?
- Yes, you can heat a ham in a slow cooker if it fits. This is an excellent method for keeping the meat moist. Add a small amount of liquid to the bottom and cook on low for 4 to 6 hours. However, you won’t get the same caramelized crust that an oven provides unless you finish it under the broiler for a few minutes.
- Do I need to wash the ham before putting it in the oven?
- No, you should never wash raw or precooked meat. Rinsing the ham can splash bacteria around your kitchen sink and countertops. Any surface bacteria will be destroyed by the heat of the oven, and the brine is already part of the flavor profile.
- What should I do if my ham is too salty?
- If you suspect the ham is overly salty, you can soak it in cold water for a few hours before heating, changing the water every hour. For a precooked ham that is already being heated, using a sweet glaze like honey or maple syrup helps balance the saltiness on the palate.
- 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 pan. This protects the individual slices from direct exposure to the air. Additionally, ensure the foil wrap is very tight and consider adding a bit more liquid to the bottom of the pan to increase steam.
- How many people will a ham feed?
- As a general rule of thumb, plan for about 3/4 pound of bone-in ham per person, or 1/2 pound of boneless ham per person. This accounts for the weight of the bone and ensures you have enough for everyone to have seconds, with a little left over for sandwiches the next day.