I’ll start with an aside: Over dinner a while back, upon hearing me use the term “high altitude” in reference to cooking, my friend Steve kindly corrected me, explaining that what we’re talking about is actually high-elevation cooking. See, altitude refers to things hanging out above the earth’s surface (like a bird, or a plane. Or Superman!). Elevation refers to the distance land rises above sea level. As a former English major and a person who generally finds rules and logic comforting, this was a deeply satisfying revelation (I’m also a fan of the Oxford comma, by the way. Wynken, Blynken, and Nod, people. It’s the only way). HOWEVER. I also understand that the accepted terminology is “high altitude cooking.” And it would be a long haul to change that convention. So high-altitude is what we’re gonna say here. Even though we know it’s wrong.
Okay, dispensing with that, let’s talk about what happens when we cook way up high. If you’ve baked anything from a mix, or perused the back of a Toll House bag, you may have noticed “high altitude” directions. Folks who live where I live, at 9,600 feet, enjoy rolling our eyes at those directions. They sometimes work, but usually … no. One size does not fit all. It’s important to understand that the effects of altitude are magnified as you go up in elevation. Meaning, a recipe that works at 5,000 feet might need further adjustments at 7,500 feet, and radical changes at 10,000 feet. I live at 9,600 feet, so my recipes are adjusted accordingly. If you live lower (or, bless you, higher), you may need to make a few tweaks (see Adjustments, below) to the recipes on the blog.
Here’s a rundown of the major factors:
MOISTURE
It’s dry up here, folks. Deee-rrrryyy. Lack of humidity is great for keeping your hair frizz-free, but if you try to make your grandma’s snickerdoodle recipe from Florida, you’re likely to be disappointed.
The higher the elevation, the faster moisture evaporates. In cooking, this can result in an unintended change in the ratio of liquid to solids. The liquid in your freshly-made cake batter, for example, can quickly and silently begin evaporating – without any visible sign – to the point that your recipe ends up with a too-high concentration of sweetener, fat, and flour, and not enough moisture. This can alter the structure and texture of the recipe and result in a sunken cake that’s dry around the edges and raw in the middle.
LEAVENING
At high elevations, the atmospheric pressure is lower. Leavening gases produced by baking soda, baking powder, or yeast are what help baked goods puff up and rise, but with less atmospheric pressure forcing them down, they can rise up fast, all hysterical-like, and then fall flat. Wah-wah. This overbubbling of gases can also affect the texture of cakes and cookies by producing a coarse, rather than small and tender crumb, and even result in total collapse (due to expanding and bursting cell walls). In my experience, this is usually an issue only for cakes and cookies; muffins and loaf-type cakes are not usually at risk of falling (though they sometimes still need adjustments for texture and moisture).
TEMPERATURE
As elevation rises, water boils at increasingly lower temperatures (around 195°F at 9,500 feet, compared to 212°F at sea level). Foods cooked in water (such as custard), by water (such as steamed vegetables), or containing a lot of liquid (such as a cake) can take longer to set or finish than you might be used to.
When baking, you may want to play around with setting your oven temperature a little higher (15 degrees or so) in order to give your recipe a chance to set quickly before it over-expands and collapses. But check baking duration carefully. And sometimes, baking temp needs to be decreased, not increased. It’s complicated. We’ll figure it out together.
FLAVOR
The dryness that sapped the moisture from your cake batter also, of course, affects your body. Dryness affects the tissues in our noses (and hence our ability to detect nuances of scent which are integral to taste) as well as our taste buds. Here’s a fun party trick: stick out your tongue and wipe it dry with a paper towel. Then sprinkle a little sugar on it. Nothing much, right? Then stick your tongue back in your moist mouth (sorry for saying moist). Voila – sweet! Proof that moisture affects flavor perception. Science is neat.
A 2010 German study testing airline food found that elevation can reduce our perception of sweet, salty, and spicy flavors by up to 30%. Here on earth we’re talking about elevations of 5,000-10,000 feet, not 30,000 feet, but anyone who has spent significant time at high elevation knows how it can sap you of moisture (and has the wrinkles to prove it).
When it comes to baked goods, be aware that adjusting recommended amounts of sugar is tricky because it affects structure and texture as well as flavor. Generally, it’s not wise to add more sugar to a recipe- in fact, cookies and cakes often benefit from reducing sugar for added physical stability. But adding a bit more salt can, interestingly, intensify the flavor of sugar. I almost always increase salt and spices by at least little bit in my recipes.
ADJUSTMENTS FOR BAKING
I am reluctant to advise on “standard” adjustments because every recipe is different and what works beautifully for one type of recipe may bomb completely in another. And many recipes need little or no adjustment from standard sea-level directions. That said, below are some across-the-board adjustments you can try if your recipe is flopping. You may need to experiment a bit with more than one approach.
IF YOUR COOKIES SPREAD AND/OR ARE DRY
… increase flour (one tablespoon per cup) for strength (but beware, too much flour can make cookies and bars tough and dry)
… decrease sugar (two tablespoons per cup)
… add an egg or egg yolk (for extra moisture and stabilizing protein)
… decrease baking soda/powder (about 1/4 tsp per tsp)
… raise oven temp by 15-25 degrees and watch carefully for doneness (could be faster or slower than recommended time)
IF YOUR CAKE COLLAPSES, IS DRY, OR IS NOT COOKED EVENLY
… add a bit more liquid (2-3 tablespoons per cup)
… replace milk with buttermilk, or mix in a little lemon juice (acidity helps batter set faster)
… increase flour (two tablespoons per cup)
… add an egg (for moisture and stabilizing protein)
… decrease sugar (two tablespoons per cup)
… decrease baking soda/powder (about 1/4 tsp per tsp)
… don’t overmix (and whip too much air into the batter)
… raise oven temp by 15 degrees and watch carefully for doneness (could be faster or slower than recommended time)
IF YOUR RECIPE TASTES FLAT OR BLAND
… increase salt and spices by 1/4 -1/2 tsp per tsp
… get creative with other flavorings: use extracts, coffee, citrus zest, nuts, etc. to add complementary nuances.