Q. Can you please explain the formula for temperature adjustment at high altitude for making toffee?
A. High altitude can do strange things to the baking and candy-making process. Reliable, time-tested recipes suddenly fail, producing fallen cakes, burnt pastries, or sticky candy. The thinner air at higher altitudes means adjustments to recipes, ingredients, or procedures are often necessary to produce satisfactory results. Fortunately, there is a formula for candy-making that makes it easy to know how to adjust your recipes. For every 500 feet above sea level, subtract 1 degree F from the required candy temperature. So if you are at 2000 feet above sea level, and you're making caramels that require you to cook them to 245 degrees F, you would instead cook your caramels to 241 F.
Truthfully, this formula comes from some of my cooking reference books. I personally live at sea level, and have never tried making candy at high altitudes, so I would love to hear from readers who have. If you live at high altitude, what adjustments, if any, do you make in your candy-making or baking? Have you noticed a difference in your recipes compared to when you make them at sea level? Are there any recipes that just won't work, no matter what changes you try?