Cooking the perfect ham centerpiece is a highlight of any holiday feast, but the real challenge often lies in the reheating process. Whether you are dealing with a massive bone-in holiday ham or a convenient spiral-sliced variety, knowing exactly how long to heat up ham is the difference between a succulent, flavorful meal and a dry, disappointing one. Most hams purchased at the grocery store are labeled as fully cooked or ready to eat, which means your goal isn’t to cook the meat from scratch, but rather to gently warm it to the ideal serving temperature.
Understanding Your Ham Type Before Heating
The time required to heat your ham depends heavily on its preparation style. Before you set your timer, identify which category your ham falls into.
Fully Cooked vs. Raw Ham
A fully cooked ham has already been cured, smoked, or baked. These are safe to eat cold, but most people prefer them warm. For these, you are simply looking to reach an internal temperature of 140 degrees Fahrenheit. On the other hand, a fresh or raw ham (often labeled “cook before eating“) requires a much longer duration and a higher final internal temperature of 145 degrees Fahrenheit followed by a three-minute rest.
Spiral Sliced vs. Whole Hams
Spiral-sliced hams are pre-cut in a continuous circle around the bone. While convenient for serving, they are much more prone to drying out because the heat can penetrate the slices more quickly. Whole or “city” hams that have not been sliced retain moisture better and can handle slightly longer durations in the oven.
The Best Way to Heat Up Ham in the Oven
The oven remains the gold standard for heating a large ham because it provides even, indirect heat. The secret to success is the “low and slow” approach. Blasting a ham at high temperatures will cause the exterior to toughen before the center is even lukewarm.
To start, preheat your oven to 325 degrees Fahrenheit. This temperature is high enough to warm the meat efficiently but low enough to prevent the sugars in the glaze from burning too quickly.
Calculation by Weight
As a general rule of thumb, you should plan for 10 to 15 minutes per pound for a whole, bone-in ham. For a boneless ham, the density is higher, so you might need closer to 15 to 20 minutes per pound. If you are heating a spiral-sliced ham, the time is reduced to about 10 minutes per pound because the heat moves through the slices faster.
Moisture Control Steps
To ensure your ham stays juicy, place it cut-side down in a roasting pan. Add about half an inch of liquid to the bottom of the pan—water, apple juice, or even a bit of white wine works beautifully. The most critical step is to cover the pan tightly with heavy-duty aluminum foil. This creates a steam chamber that prevents the natural juices of the meat from evaporating.
How Long to Heat Up Ham in a Slow Cooker
If you need to free up oven space for side dishes, the slow cooker is an excellent alternative. It is essentially a self-basting environment that is nearly foolproof for preventing dryness.
For a 5 to 7 pound ham, you will typically need 5 to 6 hours on the low setting. While you can use the high setting to cut the time down to about 3 hours, the low setting is preferred for the best texture. Since most slow cookers are oval-shaped, make sure your ham fits properly so the lid can close completely. If the ham is too tall, you can create a “foil tent” over the top and then place the lid on as securely as possible to trap the heat.
Using an Air Fryer for Smaller Portions
The air fryer has become a popular tool for smaller ham roasts, typically those weighing between 2 and 4 pounds. Because air fryers use rapid air circulation, they are incredibly efficient.
Set your air fryer to 300 degrees Fahrenheit. Wrap the ham tightly in foil to protect it from the direct blast of the heating element. A 3-pound ham will generally take about 40 to 45 minutes to reach the desired temperature. If you want a crispy exterior, you can open the foil during the last 3 to 5 minutes of the process and increase the heat to 380 degrees Fahrenheit.
Mastering the Glaze Without Burning
The glaze is often the best part of a ham, but timing is everything. Most glazes contain high amounts of sugar, honey, or maple syrup, all of which burn at relatively low temperatures.
If you apply the glaze at the beginning of a two-hour heating cycle, you will end up with a blackened, bitter crust. Instead, wait until the last 20 to 30 minutes of the heating time. Remove the ham from the oven, increase the temperature to 400 degrees Fahrenheit or 425 degrees Fahrenheit, and brush the glaze generously over the surface. Return it to the oven uncovered, allowing the glaze to bubble and caramelize into a beautiful mahogany finish.
Safety Guidelines and Internal Temperatures
While the clock is a helpful guide, a meat thermometer is the only way to be 100 percent sure your ham is ready. For a ham that was packaged in a USDA-inspected plant, the target internal temperature is 140 degrees Fahrenheit. If you are reheating a ham that was previously cooked and then refrigerated at home (leftovers), the USDA recommends heating it to 165 degrees Fahrenheit to ensure any potential bacteria are eliminated.
Always insert the thermometer into the thickest part of the meat, making sure not to touch the bone, as the bone conducts heat differently and can give an inaccurate reading. Once the ham reaches the target temperature, let it rest for 15 to 20 minutes before slicing. This resting period allows the juices to redistribute, ensuring every bite is as moist as the first.
FAQs
How long do I heat a 10 pound ham?
For a 10 pound fully cooked bone-in ham in an oven set to 325 degrees Fahrenheit, you should plan for approximately 1 hour and 40 minutes to 2 hours and 30 minutes. The specific time depends on whether the ham is spiral-sliced or whole, but checking the internal temperature starting at the 90-minute mark is recommended.
Can I heat a ham from frozen?
It is strongly recommended to thaw your ham completely in the refrigerator before heating. Heating a frozen ham will result in an unevenly cooked product where the outside is dry and the inside remains cold. Thawing usually takes about 4 to 6 hours per pound. If you must cook from frozen, you will need to increase the heating time by at least 50 percent and keep the ham strictly covered to prevent drying.
Should I wrap the ham in foil?
Yes, wrapping the ham in foil is the best way to retain moisture. For spiral-sliced hams, it is almost mandatory, as the slices provide more surface area for moisture to escape. Use heavy-duty foil and ensure a tight seal around the edges of the roasting pan to trap steam inside.
Is it better to heat ham on high or low heat?
Low heat is always better for reheating ham. High heat (above 350 degrees Fahrenheit) causes the muscle fibers to contract and squeeze out moisture, leading to a rubbery texture. A temperature of 275 degrees Fahrenheit to 325 degrees Fahrenheit is the sweet spot for a juicy result.
How do I prevent my ham from drying out?
To prevent a dry ham, use a roasting pan with a small amount of liquid (water or juice) in the bottom, wrap the ham tightly in foil, and heat it “cut-side down.” Additionally, avoid overcooking by using a meat thermometer to pull the ham out of the oven exactly when it hits 140 degrees Fahrenheit.