Does cooking vary according to the altitude?

When I visit my daughter in the French Alps, I often cook traditional Quebec recipes. On more than one occasion, the usual cooking time has turned out to be too short and I’ve had to raise the oven temperature. Is there a standard conversion factor? Is elevation an issue for Canadian cooks?

The higher you go, the lower the atmospheric pressure and the lower the boiling point of a liquid—boiling water isn’t as hot in the mountains as at lower elevations, so food takes longer to cook. At sea level, water boils at 100°C (212°F). For every 293 metres (961 feet) in elevation, the boiling point drops 1°C (1.8°F). That means water boils at about 96.6°C (206°F) where your daughter lives. The difference may seem small, but it’s enough to affect cooking times and oven temperatures. When cooking on the stove, the only way to speed things up is to use a pressure cooker; otherwise, you’ll just have to allow more time. When baking and roasting, you should add 15°C (25°F) to the specified oven temperature. If you’re baking cakes and muffins, it’s also wise to reduce your leavening agents (baking powder, baking soda) by 10% or 0.5 ml (1/8 teaspoon) for every 5 ml (1teaspoon) called for in the recipe. The majority of Canadians don’t have to worry about the effects of elevation: most people in Ontario, Quebec, British Columbia and the Atlantic provinces live less than 100 metres above sea level, where the drop in boiling point isn’t measurable with standard kitchen thermometers. At nearly 1,100 metres—high enough to bring water’s boiling point down to about 96.2°C (205°F)—Calgary is the country’s highest major city. Residents of Edmonton (668 m) and Regina (577 m) will see a noticeable but minimal difference.