A fully cooked ham is one of the most convenient centerpieces you can choose for a holiday feast, a Sunday dinner, or a large family gathering. Because the meat has already been cured and smoked (or boiled), you aren’t actually “cooking” it in the traditional sense. Instead, your goal is to preserve the flavor, maintain the moisture, and bring it up to a palatable, safe temperature without turning it into a dry, salty brick. Knowing exactly how long to heat a fully cooked ham is the difference between a succulent, tender slice of meat and a dinner disaster.
In this comprehensive guide, we will break down the timing for various types of ham, the best methods for heating, and how to ensure your dinner remains the star of the show.
Understanding Your Ham Type
Before you set your timer, you must identify what kind of ham you have sitting in your refrigerator. Not all “fully cooked” hams are created equal, and their shape and preparation style will dictate your oven time.
Boneless vs. Bone-In Hams
Boneless hams are often pressed into a round or oval shape. These heat relatively quickly because the heat can penetrate the center without the obstruction of a bone. Bone-in hams, however, offer superior flavor and a more traditional appearance. The bone acts as a conductor of heat but also adds mass, meaning these usually require a bit more time per pound to reach the desired internal temperature.
Spiral Cut vs. Whole Hams
The spiral-cut ham is a modern convenience favorite. It comes pre-sliced all the way to the bone, making serving a breeze. However, because the meat is already sliced, it is significantly more prone to drying out. If you are heating a spiral-cut ham, your timing and moisture-locking techniques (like foil wrapping) are more critical than with a whole, unsliced ham.
The Standard Rule of Thumb for Timing
The most reliable way to calculate your heating time is by weight. For a standard oven set to 325°F, you can generally follow these estimates to reach an internal temperature of 140°F:
- Whole Bone-In Ham: 18 to 24 minutes per pound.
- Half Bone-In Ham: 22 to 25 minutes per pound.
- Boneless Ham: 15 to 20 minutes per pound.
- Spiral-Sliced Ham: 10 to 15 minutes per pound (lower timing is better to avoid drying).
If your ham is exceptionally large (over 15 pounds), you may find that the outer layers begin to overcook before the center is warm. In these cases, it is often better to aim for the lower end of the time spectrum and rely on a meat thermometer.
Step-by-Step Instructions for Oven Heating
The oven is the most common and effective tool for reheating a ham. To ensure the meat stays juicy, follow this structured approach.
Preparation and Preheating
Start by preheating your oven to 325°F. While the oven warms up, remove the ham from its packaging. If there is a plastic disc over the bone, be sure to discard it. Place the ham in a heavy roasting pan. For bone-in hams, placing the flat side down (the cut side) helps keep the juices inside the meat.
Adding Moisture
Since the oven is a dry heat environment, you need to create a “steam room” for your ham. Pour about a half-inch of liquid into the bottom of the pan. Plain water works, but for added flavor, consider using apple cider, pineapple juice, or even a splash of ginger ale. This liquid creates steam that circulates under the foil.
Wrapping Securely
Tightly cover the roasting pan with heavy-duty aluminum foil. If the ham is too tall for the pan, you can create a “tent” with the foil, ensuring the edges are crimped tightly against the rim of the pan. This prevents the moisture from escaping.
Advanced Heating Methods
While the oven is the gold standard, other appliances can be used depending on your schedule and the size of the ham.
The Slow Cooker Method
If you have a smaller ham (usually 5 to 8 pounds) or a boneless variety, the slow cooker is an excellent tool for maintaining moisture. Place the ham in the crock, add a half cup of liquid, and heat on “Low” for 4 to 6 hours. Because the slow cooker uses trapped steam, the ham remains incredibly tender. Check the internal temperature after 4 hours to ensure you don’t overprocess the meat.
The Roaster Oven
For very large gatherings where your main oven is occupied by side dishes, a standalone electric roaster oven is a lifesaver. Set it to 325°F and follow the same timing rules as a conventional oven. Because roaster ovens are smaller and more contained, they often cook slightly faster, so start checking the temperature about 30 minutes before the calculated end time.
The Role of the Glaze
The glaze is what gives a holiday ham its signature “wow” factor. However, timing the glaze is a common mistake.
Most glazes contain high amounts of sugar (honey, brown sugar, or maple syrup), which can burn easily. Do not apply the glaze at the beginning of the heating process. Instead, wait until the ham has reached about 130°F (usually about 20 to 30 minutes before it is finished). Remove the ham from the oven, increase the temperature to 400°F, and brush the glaze liberally over the surface. Return it to the oven uncovered for the remaining time until the glaze is bubbly and caramelized.
Safety and Temperature Standards
According to the USDA, a “fully cooked” ham that was packaged in a federally inspected plant can technically be eaten cold right out of the package. However, if you are reheating it for a meal, it should reach an internal temperature of 140°F.
If you have a ham that was not packaged in a federal plant (perhaps from a local butcher or a “fresh” ham that you cooked yourself previously), it must be reheated to a safer 165°F. Always use a digital meat thermometer inserted into the thickest part of the meat, making sure not to touch the bone, which can give an inaccurately high reading.
Resting the Meat
Once the timer goes off and the thermometer confirms your ham has reached 140°F, the most important step begins: the rest. Remove the ham from the oven and let it sit, still covered in foil, for at least 15 to 20 minutes.
During this time, the juices that have been pushed to the surface by the heat will redistribute throughout the meat. If you slice the ham immediately, those juices will run out onto the cutting board, leaving the meat dry. Resting also allows the internal temperature to rise slightly (carryover cooking), ensuring a warm center.
Troubleshooting Common Issues
What if the ham is still cold in the middle?
If your timer goes off but the center is still chilly, don’t panic. Re-wrap the foil tightly and add another 15 to 20 minutes. If the outside is getting too dark, lower the oven temperature to 300°F to allow the heat to penetrate more slowly.
How to fix a dry ham?
If you accidentally overcooked the ham and it feels dry, your best friend is the pan sauce. Take the juices from the bottom of the roasting pan, whisk in a little Dijon mustard and honey, and drizzle it over the slices before serving. This adds immediate moisture and fat back into the meat.
FAQs
Can I heat a fully cooked ham from frozen?
It is highly recommended to thaw your ham completely in the refrigerator before heating. Thawing usually takes 24 to 48 hours depending on the size. If you must heat it from frozen, you will need to increase the heating time by approximately 50 percent and keep it tightly covered to prevent the exterior from drying out while the interior thaws.
Do I need to score the ham?
Scoring is not strictly necessary for heating, but it is excellent for aesthetics and flavor. If you are using a glaze, cutting a diamond pattern about a quarter-inch deep into the fat layer allows the glaze to penetrate the meat and creates those beautiful crispy edges.
How do I keep a spiral-cut ham from drying out?
Spiral-cut hams are the most delicate. To keep them moist, heat them “face down” in the pan, wrap them very tightly in foil, and consider adding a bit more liquid to the bottom of the pan. Avoid overcooking; once it hits 140°F, take it out immediately.
What is the best liquid to put in the roasting pan?
While water works, flavorful liquids are better. Pineapple juice is a classic pairing for ham. Other great options include orange juice, apple juice, dry white wine, or even a mixture of water and balsamic vinegar.
How long can I keep leftover heated ham?
Once you have reheated your ham, leftovers should be refrigerated within two hours. They will stay fresh in the fridge for 3 to 5 days. For longer storage, you can freeze the slices for up to two months. Leftover ham is perfect for split pea soup, breakfast omelets, or classic ham and cheese sliders.