Cooking Thanksgiving at high altitude: what changes for the turkey, the sides and the pies

USDA FSIS says most cookbooks count 3,000 feet and above as high altitude. Up there the air pressure is lower, so water boils at a lower temperature and moisture evaporates faster. Altitude doesn't change the oven, though. Here is how that plays out across the Thanksgiving menu.

What changes and what doesn't

Dish or method	At altitude	Source
Roast turkey in the oven	No change. Sea-level times and temperatures (325°F, USDA's timetable, 165°F)	USDA FSIS
Boiled potatoes, simmered stock, giblets, braises	Longer. Up to a quarter more time at 5,000 feet for simmered meat	USDA FSIS
Gravy, cranberry sauce, anything reduced	Evaporates faster; cover pots and watch thickness	USDA FSIS
Slow cooker sides	Simmers cooler; start on high	USDA FSIS
Pressure cooker	Most useful tool up high; follow the maker's altitude adjustment	USDA FSIS
Hard-cooked eggs (deviled eggs)	Longer	Colorado State
Yeast rolls	Rise faster; watch the dough, not the clock	Colorado State
Pie crust	Little change; bake in the lower third	Colorado State
Cream-pie fillings and puddings	Above 5,000 feet, cook over direct heat	Colorado State
Cakes and quick breads	Above 3,000 feet: hotter oven, less leavening and sugar, more liquid	Colorado State
Candy, caramel, candied nuts	Lower the finishing temperature	Colorado State

How much lower water boils

Colorado State University Extension's table:

Elevation	Water boils at
Sea level	212°F
2,000 feet	208°F
5,000 feet	203°F
7,500 feet	198°F
10,000 feet	193°F

USDA's rule of thumb is a drop of just under 1°F for every 500 feet. Water at a rolling boil in Denver is still about 9°F cooler than at sea level, so it cooks more slowly.

The turkey

USDA FSIS says oven temperatures aren't affected by altitude: use the sea-level times and temperatures for oven-roasting meat and poultry. Roast at 325°F on the USDA timetable, rest it 20 minutes, and check for 165°F in the thickest part of the breast, the innermost thigh and the innermost wing. The thermometer guide shows the three spots.

Two things still change:

• Drier air. USDA notes that foods dry out faster at altitude and suggests covering them during cooking. A loose foil tent over the breast once it has browned, or an oven bag, keeps more moisture in.
• Braised or simmered turkey parts. Legs, wings or a neck cooked in liquid follow the moist-heat rule: up to a quarter more time at 5,000 feet.

Frying. USDA's general altitude advice for deep-fat frying is to lower the oil temperature about 3°F for every 1,000 feet, so food doesn't brown outside before it cooks inside. USDA doesn't publish a separate altitude number for whole turkeys, and the fire safety checklist explains why fire officials discourage oil fryers. If you fry anyway, the thermometer has the final say.

Sides, gravy and stock

• Potatoes and root vegetables boil cooler, so they take longer. Start them earlier than the recipe says and test with a fork.
• Giblet or neck stock for gravy simmers longer. The giblets guide has the method; allow up to a quarter more time at 5,000 feet.
• Gravy and sauces evaporate faster. Keep a lid on the pot and a little extra broth on hand.
• Stuffing dries out faster. Cover the dish, and bake it to 165°F whether it's in the bird or not.
• Deviled eggs. Colorado State's example is that a 3-minute egg can take 5 minutes at 5,000 feet. Hard-cooked eggs need extra time too, so cut one open before you peel the batch.

The sides timing guide gives the sea-level order. Up high, move the boiled items earlier in that order.

Slow cookers and pressure cookers

USDA says slow cookers simmer at a lower temperature up high, so:

• Use a setting that keeps the food at 200°F or higher; check with a thermometer.
• Start on high for the first hour.
• Don't lift the lid. USDA says each peek can cost 20 minutes or more of heat recovery.
• Put thawed food in, never frozen.

USDA calls a pressure cooker a necessity for many foods at high altitude, because it raises the boiling point back up. Use the altitude adjustment in your cooker's manual.

Pies, rolls and cakes

Pies. Colorado State says pie crusts generally aren't affected, though a little more liquid may help the texture. Bake in the lower third of the oven so the bottom crust doesn't go soggy. For cream pies and puddings above 5,000 feet, cook the filling over direct heat rather than in a double boiler. The pie timeline covers baking and storage.

Yeast rolls. Dough rises faster at altitude. Colorado State suggests letting it rise only until just doubled, using a little less yeast or punching it down for a second rise, and choosing flour with at least 12 percent protein. Watch the dough, not the clock.

Cakes and quick breads. Above 3,000 feet, Colorado State's adjustments for each teaspoon of baking powder and each cup of sugar and liquid in the recipe:

Change	3,000–6,500 ft	6,500–8,500 ft	8,500–10,000 ft
Baking powder, per teaspoon	Reduce 1/8 tsp	Reduce 1/8 to 1/4 tsp	Reduce 1/4 tsp
Sugar, per cup	Reduce 0 to 1 Tbsp	Reduce 0 to 2 Tbsp	Reduce 1 to 3 Tbsp
Liquid, per cup	Add 1 to 2 Tbsp	Add 2 to 4 Tbsp	Add 3 to 4 Tbsp
Oven temperature	Raise 15 to 25°F	Raise 15 to 25°F	Raise 15 to 25°F

Start with the smaller change. Colorado State's guide notes that cookies usually need only small changes; chilling the dough helps keep them from spreading.

Candy, caramel and candied pecans. Colorado State says to lower the finishing temperature by about 2°F for every 1,000 feet. To be exact, boil water, read your thermometer, and subtract that from 212°F. Lower the recipe's temperature by the difference.

Food safety doesn't change

Altitude changes how long food takes to cook, not the safe temperatures. Cook poultry and stuffing to 165°F and reheat leftovers to 165°F. Keep hot food at 140°F or above and get it into the fridge within 2 hours. The buffet guide and leftovers guide have the rest.