How to heat a spiral ham without drying it out: times, temperatures and the USDA safety rules

A spiral ham from the store is already cooked. Heating it is a warming job, not a cooking job, and the usual mistake is leaving it in too long: the slices are cut all the way to the bone, so they dry out fast. USDA FSIS publishes the method and the safe temperatures. Read the label first, because the times and the target temperature depend on what kind of ham you bought.

Read the label first

Label says	What it means	Heat to
Fully cooked / ready to eat, packed at a USDA-inspected plant (most spiral hams)	Safe to eat cold; you're only warming it	140°F
Cooked, but repackaged at the store (deli-wrapped)	Treat as a leftover	165°F
Cook before eating, or a fresh ham	Raw or partly cooked	145°F, then rest 3 minutes
Leftover cooked ham	Already cooked once	165°F

USDA FSIS says a ham that needs cooking but looks ready to eat must carry a prominent statement such as "cook thoroughly" and cooking directions on the label. FoodSafety.gov's chart gives the same temperatures.

How to heat a spiral ham (USDA's method)

1. Take it out of the packaging and set it in a roasting pan; a half ham sits steadiest cut side down. Save any glaze packet for the end.
2. Cover the entire ham with heavy aluminum foil, sealed at the edges. That's USDA's instruction for reheating a spiral-sliced ham in a conventional oven.
3. Heat at 325°F for about 10 minutes per pound. An 8 lb half ham is roughly 80 minutes. USDA's oven temperature for ham is never below 325°F.
4. Check the center, away from the bone, for 140°F. A leave-in probe means you don't have to unwrap it to look; the thermometer guide covers placement and the ice-water accuracy check.
5. Glaze at the end, uncovered. USDA notes that heating makes glaze melt and run off, so add it when the ham is nearly hot and put it back in uncovered just long enough to set. Sugar glazes scorch quickly, so watch it.
6. Cut along the bone to free the slices and serve. Only need a few slices? FSIS says individual slices can be warmed in a skillet or microwave.

Prefer it cold? USDA says spiral hams are best served cold, for the same reason: heating dries them and runs the glaze. A cold or room-temperature platter also frees the oven for everything else, which matters on a one-oven day. The one-oven schedule shows where a ham fits around the turkey and sides.

USDA ham timetable (oven at 325°F)

Cook before eating (heat to 145°F, rest 3 minutes):

Cut	Weight	Minutes per pound
Whole, bone-in	10–14 lb	18–20
Half, bone-in	5–7 lb	22–25
Shank or butt portion, bone-in	3–4 lb	35–40
Arm picnic shoulder, boneless	5–8 lb	30–35
Shoulder roll (butt), boneless	2–4 lb	35–40

Fully cooked (warm to 140°F; 165°F if repackaged or leftover):

Cut	Weight	Minutes per pound
Vacuum-packed, boneless	6–12 lb	10–15
Spiral cut, whole or half	7–9 lb	10–18
Whole, bone-in	10–14 lb	15–18
Half, bone-in	5–7 lb	18–24
Arm picnic shoulder, boneless	5–8 lb	25–30
Canned ham, boneless	3–10 lb	15–20

Fresh ham, uncooked (cook to 145°F, rest 3 minutes): whole leg, bone-in, 12–16 lb: 22–26 minutes per pound; whole leg, boneless, 10–14 lb: 24–28; half, bone-in, 5–8 lb: 35–40.

Country ham is dry-cured and salty. USDA says to soak it 4 to 12 hours (or longer) in the refrigerator to cut the salt, cover it with water and boil it 20 to 25 minutes per pound, then drain, glaze and brown it at 400°F for 15 minutes. FSIS also says to follow the manufacturer's cooking instructions.

How much to buy

USDA's serving guide: 1/4 to 1/3 lb per person for boneless ham and 1/3 to 1/2 lb per person for bone-in (which includes spiral hams). For 12 people that works out to roughly 4 to 6 lb bone-in at the upper end, more if you want leftovers. If ham is a second main next to the turkey, the food-per-person guide has the turkey numbers to balance against.

Holding and leftovers

• On the buffet: USDA says to keep hot ham at 140°F or above, or serve it cold. The buffet guide covers chafing dishes and the 2-hour rule.
• Refrigerate within 2 hours of coming out of the oven, in shallow containers.
• Storage times (USDA FSIS): spiral-cut ham and cooked leftovers, 3 to 5 days in the fridge or 1 to 2 months frozen. A whole cooked ham in its store wrap, 7 days; a store-wrapped half or slices, 3 to 5 days. An unopened vacuum-sealed cooked ham with no date, 2 weeks (or the use-by date if it has one). Canned, shelf-stable ham, 2 years in the pantry. An uncut country ham, up to a year at room temperature.
• Reheating leftovers: to 165°F. The leftovers guide has the full fridge-and-freezer chart for the rest of the meal.