Sea level recipes will typically fall into a gooey mess that never really completely sets up. If it does manage to rise and set before it falls, the cake is often coarse in texture, dry, and dense. What's the secret for successful cake baking at this altitude?
One big clue is the PH of the batter. In high altitude situations, cake batters need to set up faster to avoid falling in the oven. It just so happens that an acidic batter will set-up faster in the oven, preventing an extended baking time which can dry out a cake. Also, the faster a cake sets up after it has risen, the less chance it has of falling into an unsightly mess. Increasing the acidity of a batter can be as simple as swapping out the milk in a recipe for low-fat buttermilk, or using sour cream, or plain yougurt in a batter.
Another baking trick is strengthening the cake structure. This is usually done by decreasing the sugar a bit, adding a bit more flour, and usually adding an extra egg. Also, for cake recipes that call for dutch processed cocoa, natural cocoa is always preferred in high altitude cake baking. The extra acidity from the natural cocoa helps to strengthen the cake batter.
High altitude cakes also typically need their leavening agents decreased from anywhere from 1/4 tsp. to 1/2 tsp (this depends on the elevation and the individual make-up of the recipe). Leavening agents (here, we are talking about baking powder and baking soda) simply work better at high altitudes because of lower air pressure. Simply speaking, there is less weight (air pressure) pressing down on the surface of the cake, so it takes less work from the leavening agents to make a cake rise. Too much leavening will cause a cake to either bubble over in the oven or cause the cake to rise too fast before the structure is finished setting--causing the cake to eventually collapse.
The last adjustment for a high altitude cake is increasing the moisture to prevent a dry cake. This is typically done by increasing the liquid (often buttermilk) by a couple of tablespoons.
For a more detailed look at high altitude cake baking and for some really great recipes that work at a variety of altitudes, I highly recommend the book Pie in the Sky: High Altitude Baking. This amazing book is written by Susan Purdy, who meticulously tested and retested a wide variety of baking recipes at several different altitudes--including 10,000 feet. It's an invaluable resource that I use constantly.
This cake, Basic 1-2-3-4 Cake, is an old American standby. It's been around since the introduction of baking powder and baking soda (baking powder is a combination of soda and cream of tartar--a by-product of an acidic mold naturally found on grape skins). By the beginning of the 20th century, every housewife and hired household cook knew this recipe by heart. With the advent of the electric hand mixer in the early 40's, this cake was a standard addition to every dessert and coffee table in America.
Not only is this cake easy and fast to whip up, it is extremely versatile, lending itself to any combination of flavor additions and frostings.
This 5,000ft version swaps out the traditional milk for buttermilk (for acidity), and the cake is strengthened by decreasing the sugar and leavening, and increasing the flour and the egg. Also, the buttermilk is slightly increased to keep it moist.
The standard flavoring is usually vanilla, but you can use any combination of extracts up to 3 tsp. My favorite is 1.5 tsp vanilla and 1.5 tsp lemon extract.
Basic 1-2-3-4 Cake for 5,000 feet
Pan Preparation: 2, 9 inch round cake pans or 3, 9 inch round cake pans, sprayed with flour spray (or greased and floured) and the bottoms lined with parchment rounds. If using 2, 9 inch cake pans, the layers may need to be split if you want to make a 3-4 layer cake.
Alternately, a 9x13 inch cake pan can be used, prepped as above. This recipe will also make about 15-18 standard cupcakes. Line the cupcake pan with appropriate liners and scoop batter about 2/3 full.
Oven Time & Temp: Preheat oven to 375 for standard electric oven or 350 for convection oven. Place oven rack in the center of the oven. Bake the cake layers for 25-30 minutes for standard electric oven and 20-25 minutes for convection oven. A toothpick should come out clean.
**A 9x13 inch cake will take about 30-35 minutes to bake
**Cake pans may need to be rotated about 22-26 minutes into the bake cycle, when the cake is fully risen and almost completely set and is just lightly browned on the edges.
3 c. + 3 TBS bleached, all-purpose flour, sifted first and then measured**
2 tsp. baking powder
.5 tsp. table salt
2 cups minus 2 TBS sugar
2 tsp. vanilla extract (or any combination of extracts or flavorings, up to 3 tsp. total)
5 Large, whole eggs, room temperature
1 c. + 3 TBS. low-fat buttermilk, slightly room temp (should not be chilled, let it sit at room temp for 15 minutes or so)