The centerpiece of many holiday dinners and Sunday gatherings is the ham. While it may look intimidating due to its size and weight, the majority of hams purchased at your local grocery store are “fully cooked” or “city hams.” This means the hard work—the curing and the initial cooking—has already been done for you. Your job in the kitchen isn’t actually to “cook” the meat in the traditional sense, but rather to reheat it gently so it reaches a safe, appetizing temperature without losing the juices that make it delicious.
Understanding the timing and temperature requirements is the difference between a succulent, tender slice of pork and a dry, leathery disappointment. This guide breaks down exactly how long to cook a cooked ham, the best methods for preserving moisture, and how to achieve that perfect caramelized glaze.
Determining the Type of Ham in Your Kitchen
Before you set your oven timer, you must identify exactly what kind of ham you have. Most commercial hams are labeled as “fully cooked,” but there are subtle variations that affect heating times.
Fully Cooked Bone-In Ham
These are the traditional whole or half hams. Because the bone is still present, heat travels differently through the meat. They often take a bit longer per pound than boneless versions but are widely considered to be more flavorful and moist.
Spiral-Sliced Ham
A favorite for convenience, these hams are pre-sliced all the way to the bone. While they make serving a breeze, they are much more susceptible to drying out because the heat can penetrate between the slices. They require a lower temperature and a tighter seal during the reheating process.
Boneless Ham
These hams have had the bone removed and the meat pressed into a uniform shape. They heat up more quickly and are very easy to carve, making them ideal for smaller gatherings or quick family meals.
The Science of Reheating Without Drying Out
The biggest mistake home cooks make is treating a pre-cooked ham like a raw turkey. If you blast a cooked ham at high heat for several hours, you will squeeze the moisture out of the muscle fibers, leaving the meat tough.
The USDA recommends that pre-cooked hams be reheated to an internal temperature of 140 degrees Fahrenheit. This temperature is high enough to ensure any surface bacteria are neutralized but low enough to keep the proteins from tightening and becoming rubbery.
Choosing the Right Oven Temperature
The gold standard for reheating ham is 325 degrees Fahrenheit. This “low and slow” approach allows the heat to gradually reach the center of the ham without scorching the exterior. Some experts even suggest going as low as 275 degrees Fahrenheit for spiral-sliced hams to provide even more protection against moisture loss.
The Role of Moisture and Steam
To keep your ham juicy, you should create a “steam chamber.” Place the ham in a roasting pan with about a half-cup of liquid at the bottom. Water works fine, but using apple juice, orange juice, or chicken broth adds a subtle layer of flavor. Covering the pan tightly with heavy-duty aluminum foil is the most critical step—it traps the steam and prevents the oven’s dry air from wicking away the meat’s natural juices.
Time Per Pound Guidelines for Every Cut
While every oven is different, you can estimate your total kitchen time using these standard weight-based calculations. These times are based on an oven temperature of 325 degrees Fahrenheit.
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Whole Bone-In Ham (10 to 14 Pounds)
For a massive whole ham, plan for 15 to 18 minutes per pound. This means a 12-pound ham will take roughly 3 hours to reach the target internal temperature.
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Half Bone-In Ham (5 to 7 Pounds)
Smaller half hams require slightly more time per pound because of the ratio of surface area to weight. Expect 18 to 24 minutes per pound. A 6-pound half ham will usually be ready in about 2 hours.
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Spiral-Sliced Ham
Because these are already sliced, they heat more efficiently. Aim for 10 to 12 minutes per pound. It is vital to check these hams early, as they can go from “perfect” to “dry” very quickly.
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Boneless Ham (6 to 12 Pounds)
Without the bone to act as an insulator, these hams heat up in about 10 to 15 minutes per pound.
The Art of the Perfect Glaze
The glaze is what transforms a standard ham into a showstopping centerpiece. However, timing is everything. Most glazes contain high amounts of sugar—whether from brown sugar, honey, or maple syrup. If you apply the glaze at the beginning of the cooking process, the sugar will burn long before the ham is hot in the center.
When to Apply Glaze
Wait until the last 20 to 30 minutes of the reheating time to apply your glaze. At this point, the ham should be nearly at its target temperature. Remove the foil, brush the glaze generously over the surface, and return the ham to the oven uncovered.
Increasing the Heat for Caramelization
If you want a truly crackling, caramelized crust, you can increase the oven temperature to 375 degrees Fahrenheit or 400 degrees Fahrenheit once the glaze is applied. Keep a very close eye on it; you want the sugar to bubble and brown, not turn black. Basting the ham once or twice during this final window will help build up a thick, glossy lacquer.
Essential Preparation and Finishing Steps
To ensure the best possible results, follow these professional tips for preparation and serving.
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Scoring the Ham
For non-spiral hams, use a sharp knife to score the surface of the fat in a diamond pattern, making cuts about a quarter-inch deep. This doesn’t just look beautiful; it creates channels for the glaze to seep into the meat and allows the fat to render more effectively.
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The Importance of the Rest Period
Once the ham reaches an internal temperature of 135 degrees Fahrenheit to 140 degrees Fahrenheit, remove it from the oven. Tent it loosely with foil and let it rest for 15 to 20 minutes. During this time, the juices that were pushed toward the center by the heat will redistribute throughout the meat. If you carve it immediately, those juices will run out onto the cutting board, leaving the meat dry.
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Using a Meat Thermometer
Relying on a clock alone is risky. Factors like the initial temperature of the ham and the accuracy of your oven can change the timing significantly. An instant-read meat thermometer is the only way to be 100% sure. Insert the probe into the thickest part of the meat, making sure it doesn’t touch the bone, which can give a false high reading.
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Reheating Leftover Ham Slices
If you are only reheating a few slices for a quick meal, the oven method is still preferred but can be much faster. Place the slices in a single layer in a baking dish, add a tablespoon of water or broth, and cover tightly with foil. Heat at 325 degrees Fahrenheit for about 10 minutes.
For an even faster option, you can use a skillet over medium heat with a splash of water. Flip the slices frequently to ensure they warm through without searing or drying out.
Frequently Asked Questions
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Can I eat a fully cooked ham without reheating it?
Yes, a ham labeled “fully cooked” is safe to eat cold right out of the package. It has already been heated to a safe temperature during processing. However, most people prefer the texture and flavor of the ham when it has been warmed through and glazed.
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Why did my ham turn out tough and dry?
The most common cause of dry ham is overcooking or using a temperature that is too high. If the internal temperature exceeds 145 degrees Fahrenheit, the meat begins to lose its moisture rapidly. Additionally, failing to cover the ham with foil during the majority of the reheating process allows steam to escape, which dries out the exterior.
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How long can I keep cooked ham in the refrigerator?
According to food safety guidelines, cooked ham should be consumed within 3 to 5 days if kept in a refrigerator set to 40 degrees Fahrenheit or lower. For longer storage, you can freeze the ham for up to 2 months, though the texture may change slightly upon thawing.
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Do I need to wash the ham before cooking it?
No, you should never wash raw or cooked meat. Washing meat can splash bacteria onto your kitchen surfaces, increasing the risk of cross-contamination. Simply pat the ham dry with paper towels if there is excess moisture on the surface before you begin your preparation.
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Is it better to cook ham at 325°F or 350°F?
For a pre-cooked ham, 325 degrees Fahrenheit is generally better. The lower temperature provides more even heating and significantly reduces the risk of drying out the edges before the center is warm. Use 350 degrees Fahrenheit only if you are in a significant hurry and are monitoring the internal temperature very closely.