When I first moved from California to Utah back in 2002 I had no idea what I was going to face when it came to my baking. Pan after pan of my cookies were flat frisbees and my cakes all sank in the middle. I remember thinking, "Well, I used to be able to bake." I came very close to giving up on baking cookies and cakes, which would have been such a sad thing!
I didn't know anything about how high altitudes effected baking; I didn't even know it could effect baking. Then one day a friend handed me a cookie. It was so much better than what I'd been pulling out of my oven and I asked her what recipe she used. Her response, with a shrug: "I just followed the high altitude instructions on the bag of chocolate chips."
What did ya say?
I started reading whatever I could find about high altitude baking, beginning with the directions on a similar bag of chocolate ships, and have since been able to rescue all of my sea-level recipes. A very, very happy thing :)
If you want a really good book about high altitude baking, I highly suggest Pie in the Sky by Susan G. Purdy. I thought I liked to experiment with different versions of recipes--I can't imagine how many iterations of the recipes in this book she had to go through to find the ones that worked at the various elevations! She's kind of my hero. Anyway, she has put together a very good book with explanations, etc. In fact, when I just could not get a scratch yellow cake to work, it was her book that finally filled in the gaps I was missing. I was finally successful; you can get the recipe HERE, as well as read more about my high-altitude cake adventure.
In the meantime, here are a few things I learned about high altitude baking:
1. Decrease the sugar. Sugar behaves differently at higher altitudes, though I don't know why. It could have something to do with the boiling point of water (see #3 below). Decreasing the amount of sugar seems to help with the goofiness. Unfortunately (or not, depending on how much you like to experiment, and whether or not you have people to eat all the not-perfect cookies) there isn't an exact amount or percentage that works for every cookie recipe, so it may take you a few batches to find the right amount. As an example, for the recipe for My Favorite Chocolate Chip Cookies, I decreased both the white and brown sugars from 1 cup each to 3/4 cup each.
2. Increase the flour. It doesn't take much to make a difference, usually just a tablespoon or two, to add the additional structure needed to help keep cookies from going flat, and cakes and brownies from sinking.
3. Increase the water/liquid. Water reaches its boiling point at a lower temperature the higher you go in elevation, so the idea is that you need to add a little bit more to the recipe to keep it from going dry. Again, you have to kind of experiment to find the right amount, just know that it doesn't take much, like the additional flour. And, sometimes you don't actually need any additional liquid. Did I already say it's not an inexact science? lol.
But that's basically it. Three things to monkey around with.
What's that, dear reader? What about store-bought cake and brownie mixes? First, don't follow the high-altitude instructions on the package. Then, this is what I do for store-bought mixes:
For cake mixes: Add 1 1/2 tablespoons flour to the dry mix. Replace the water with buttermilk and increase the amount to 1 1/3 cups. I don't change the oil amount but I do use melted butter instead of oil. I don't change the eggs and I don't change the oven temperature; bake until the cakes pass the toothpick test. Whys: The additional flour and the buttermilk help with stability and Sinking Cake Syndrome, and the buttermilk also cuts down on the sweetness of the store mixes. I use butter instead of oil because I like how it tastes better and because I've pretty much stopped using vegetable or canola oil.
For brownie mixes: Add 1 1/2 tablespoons flour to the dry mix. I use melted butter instead of oil in brownie mixes, too, again for taste and not-using-canola-oil reasons, not for high-altitude reasons. I also add 1 cup miniature chocolate chips, because, well, chocolate chips just make things better (exceptHomemade Hot Chocolate Mix,) I don't change the oven temperature, and I take them out of the oven while they are still pretty underdone so they will be fudgy after they've cooled; I usually bake them at 350deg for 28 minutes.
That's pretty much what I've learned--I'll add more to this page as I learn more.