If you have ever stood in the grocery store aisle staring at a shrink-wrapped ham, you have likely noticed a common label: “fully cooked.” This label is both a blessing and a source of confusion. On one hand, it means the heavy lifting of curing and smoking is already done. On the other hand, it leads to the inevitable kitchen conundrum: how long do you cook a cooked ham for without turning it into a salty piece of leather?
Since the ham is technically ready to eat right out of the package, your goal isn’t actually “cooking” in the traditional sense. Instead, you are aiming for a gentle reheating process that preserves the juices while achieving a safe and palatable internal temperature. Whether you are prepping for a holiday feast or a simple Sunday dinner, mastering the timing and temperature is the secret to a centerpiece that guests will actually want seconds of.
Understanding the Pre-Cooked Ham Basics
Before setting the timer, it is vital to understand what you are working with. Most hams sold in supermarkets are “city hams,” which means they have been wet-cured and then smoked or heated by the manufacturer. Because they have already been brought to a safe temperature during processing, you are essentially just warming them up for service.
There are three main types of pre-cooked hams you’ll encounter:
- First is the bone-in ham, which many enthusiasts swear by for better flavor and a more traditional presentation.
- Second is the boneless ham, which is easier to slice but can sometimes dry out faster if over-reheated.
- Finally, there is the spiral-cut ham, which is pre-sliced all the way to the bone. While incredibly convenient, spiral hams are the most delicate because the slices provide more surface area for moisture to escape.
General Timing Rules for Reheating
The standard rule of thumb for reheating a fully cooked ham is to aim for about 10 to 15 minutes per pound. This range accounts for different oven temperatures and ham sizes. However, the most common oven setting for this task is 325 degrees Fahrenheit. At this moderate heat, you provide enough warmth to penetrate the center of the meat without scorching the exterior.
For a whole bone-in ham weighing between 10 and 14 pounds, you should plan for a total time of about 2 to 3 hours. For a smaller half-ham, usually between 5 and 7 pounds, the time drops to roughly 1.5 to 2 hours. If you are working with a boneless ham, which is often more compact, you should lean toward the lower end of the time scale, around 10 to 12 minutes per pound.
The Importance of Internal Temperature
While time is a helpful guide, internal temperature is the only true measure of success. The USDA recommends reheating a fully cooked ham to an internal temperature of 140 degrees Fahrenheit. If the ham was not packaged in a USDA-inspected plant, you should aim for 165 degrees Fahrenheit for safety, but for the vast majority of store-bought hams, 140 degrees Fahrenheit is the magic number for peak juiciness.
Using a meat thermometer is non-negotiable here. You should insert the probe into the thickest part of the meat, making sure not to hit the bone, as the bone conducts heat differently and will give you an inaccurate reading. Once the thermometer hits 135 degrees Fahrenheit, it is time to take it out of the oven. The “carry-over cooking” that happens while the meat rests will bring it up to that final 140 degrees Fahrenheit mark perfectly.
Step-by-Step Reheating Strategy
To ensure your ham stays moist during its time in the oven, you need a strategy beyond just setting a timer. Start by removing the ham from the refrigerator about 30 to 60 minutes before you plan to cook it. This takes the chill off and allows for more even heating.
Place the ham in a roasting pan, flat-side down. To create a moist environment, add about half a cup of liquid to the bottom of the pan. This could be water, apple cider, orange juice, or even a splash of ginger ale. The liquid will steam inside the oven, preventing the meat from drying out.
The most critical step is wrapping the ham. Use heavy-duty aluminum foil to cover the entire roasting pan tightly. If you have a spiral ham, this is even more important because those pre-cut slices are prone to curling and drying. By sealing the pan, you trap the moisture inside, essentially braising the ham in its own juices.
Adding the Glaze and the Final Blast of Heat
If you are planning to use a glaze, you have to adjust your timing. Most glazes contain high amounts of sugar, which will burn if left in the oven for the entire duration. You should only apply your glaze during the last 20 to 30 minutes of the reheating process.
Once the ham reaches about 130 degrees Fahrenheit, remove it from the oven and carefully peel back the foil. Turn the oven heat up to 400 degrees Fahrenheit. Brush your glaze generously over the surface, making sure to get into the crevices of a spiral ham. Put it back in the oven, uncovered, for about 10 to 15 minutes. Watch it closely; you want the sugar to caramelize and bubble into a beautiful mahogany crust, but it can go from perfect to burnt in a matter of seconds.
Alternative Cooking Methods
The oven isn’t the only way to handle a pre-cooked ham. If your oven is occupied by side dishes, the slow cooker is a fantastic alternative. For a small to medium-sized ham, place it in the slow cooker with a bit of liquid and cook on Low for 4 to 6 hours. This method is incredibly forgiving and produces an exceptionally tender result.
If you have an electric roaster oven, follow the same time and temperature guidelines as a standard oven. These are particularly useful for large holiday gatherings when you are working with a 15-pound whole ham that might struggle to fit in a standard kitchen oven.
Resting is Not Optional
Once the ham is out of the oven, the hardest part begins: waiting. You must let the ham rest for at least 15 to 20 minutes before carving. Resting allows the muscle fibers to relax and reabsorb the juices. If you slice into it immediately, all that moisture you worked so hard to preserve will spill out onto the cutting board, leaving the meat dry. Keep it loosely tented with foil during this time to retain the heat.
Common Mistakes to Avoid
- The most common mistake is cooking the ham at too high a temperature. Some people think that cranking the oven to 400 degrees Fahrenheit will speed things up, but all this does is toughen the protein and dry out the exterior while the middle stays cold. Low and slow is always the winner for ham.
- Another mistake is over-glazing. While a thick crust is delicious, too much liquid glaze can actually wash away the natural saltiness of the ham or make the skin soggy. Balance is key.
- Finally, never skip the liquid in the pan. Even if the ham is wrapped in foil, that small amount of steam at the bottom makes a world of difference in the final texture.
Frequently Asked Questions
How long do you cook a pre-cooked ham per pound at 325 degrees Fahrenheit?
For a standard fully cooked ham, you should reheat it for 10 to 15 minutes per pound at 325 degrees Fahrenheit. This ensures the center reaches the desired 140 degrees Fahrenheit without the outside becoming overdone.
Do you have to cook a ham that is already fully cooked?
No, you do not technically “have” to cook it. Since it is fully cured and smoked, it is safe to eat cold right out of the package. However, most people prefer the texture and flavor of a ham that has been warmed through and glazed.
How do I keep my spiral ham from drying out?
The best way to keep a spiral ham moist is to wrap it tightly in heavy-duty aluminum foil and add a small amount of liquid, like water or juice, to the bottom of the roasting pan. Additionally, avoid overcooking it; once it hits 140 degrees Fahrenheit, it should be removed from the heat immediately.
Can I reheat a cooked ham in a slow cooker?
Yes, a slow cooker is an excellent tool for reheating a pre-cooked ham. Place the ham in the crock with about half a cup of liquid and cook it on the Low setting for about 4 to 6 hours until it is heated through.
What is the safe internal temperature for reheating ham?
The USDA recommends that a fully cooked ham be reheated to an internal temperature of 140 degrees Fahrenheit. If the ham was not processed in a federally inspected plant or if you are unsure of its origin, it is safer to reheat it to 165 degrees Fahrenheit.