High elevation can change the candy game. Learn essential tips & techniques for high altitude candy making, to ensure your sweets come out flawlessly every time.

Close-up of blue and white striped saltwater taffy.

🗻 Understanding the challenges of high altitude cooking

Living at a high altitude isn’t all fun and games and sweeping vistas: it can also mean frustration in the kitchen. From deflated cakes to dense bread to burnt toffee, the unique conditions created by higher elevations can wreak havoc on otherwise-reliable baking and candy recipes.

Fortunately, there are some adjustments you can make to compensate for the effects of living thousands of feet above sea level. Armed with a little knowledge and a trusty candy thermometer, you can figure out your specific altitude conditions, and learn what recipe and temperature changes you need to make for culinary success.

This guide will cover the effects of altitude on candy-making, and provide two different ways to calculate temperature adjustments. Here’s everything you need to know to make perfect high altitude toffee, fudge, caramel, and more!

Table of Contents

Hand inserting a thermometer in a a teal saucepan filled with water.

🍬 How does altitude affect candy making?

At higher elevations, water boils at a lower temperature, which can throw off traditional candy recipes calibrated for sea level conditions. Additionally, reduced air pressure can affect the structure and texture of your sweets.

What candies are affected by altitude?

When we talk about altitude and candy making, we are specifically talking about candies that start with a cooked sugar syrup, including old-fashioned fudge, caramels, toffee, taffy, and traditional fondant. Because these recipes involve boiling sugar and water together, the lower boiling point of water has a big impact on them. In these cases, you will need to reduce your target cooking temperature to account for the higher altitude. The reduction amount varies, depending on your precise elevation.

Candies that do not involve boiling water, like chocolate-based confections, aren’t affected in the same way, and you shouldn’t have to calculate temperature changes to your chocolate candies.

Pumpkin fudge in a beige box.

🌡Altitude temperature adjustments

There are two methods for determining your temperature adjustment: a simple formula, or a boiling water test. If you are using the formula method, you will still want to test and calibrate your thermometer regularly to be sure that it’s accurate.

The High Altitude Formula

This is the general formula for determining how to adjust your cooking temperature:

For every 500 feet above sea level, subtract 1° F from the final temperature.

Example: if you live at 2000 feet above sea level, you would subtract 4° from your recipes. If you were making a candy recipe that calls for the candy to be cooked to 245° F, you would only cook it to 241° F.

The benefit of using this formula is that it is SUPER easy. The downside is that it’s just a general guideline, and does not take into account how accurate (or inaccurate!) your thermometer is. For real precision, you need to put on your scientist pants and do the boiling water thermometer test.

Thermometer in a pot of boiling water to test its calibration.

The High Altitude Thermometer Test


  • Fill a medium saucepan with 3-4 inches of water. Bring the water to a rolling boil, and let it boil for 2-3 minutes before inserting your thermometer.
  • Insert your thermometer into the pot of boiling water, making sure that the bulb is fully submerged, but not touching the bottom or sides of the pan, since this can give you an inaccurate reading.
  • Keep the thermometer in the boiling water for one minute, then check the temperature. (Some digital thermometers can give a near-instant reading, but mercury thermometers usually need more time to come to temperature.)
  • If you are using a mercury thermometer, make sure you are at eye level with the temperature markings so you get an accurate reading.


At sea level, water boils at 212° F, or 100° C. Take note of your thermometer’s boiling water reading, and calculate the difference between that and 212° F. This is your temperature adjustment, and you should use it whenever candy recipes call for a specific temperature.

Example: if your thermometer displays 207° F in boiling water, that is 5 degrees less than 212° F. You now know that you need to subtract 5 degrees from your desired temperature outcome when you use that thermometer. So if a candy recipes calls for the candy to be cooked to 245° F, you should only cook it to 240° F.

Vanilla bean marshmallows on a red platter.

💡 Tips and FAQs  

  • It’s not enough to just do the thermometer test once. Over time, thermometers can become less accurate, so it’s important to test your thermometer regularly and see if your temperature adjustment number has changed.
  • If you find yourself getting wildly different numbers from test to test, or if your number is very far off from the formula estimation, test it several times in a row and see if you get consistent readings. If you don’t, it is probably time for a new thermometer.
Pot of boiling candy with a hand holding a candy thermometer in the water.

(You can see my water boils well below 212° F, because I live at a higher altitude.)

High altitude living has its share of low points, but bad candy doesn’t have to be one of them. Conquering the art of candy making at high altitudes is no small feat, but if you embrace the challenge and make the necessary adjustments, your candy skills can soar even higher than your elevation.

🍭 More Candy Tips:

Meet Elizabeth!

Hi, I’m Elizabeth — a trained pastry chef, cookbook author, video instructor, and your new Baking BFF! I’m going to teach you everything you need to know to be a sugar hero. ❤️

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  1. I’m having an issue with making English Toffee. I have made this for years but have just moved to Las Vegas and I cannot get the English Toffee to brown up. It just gets foamy and sugary. Can you please tell me how to fix this? Please help.

    1. Hi Chris, I’d be happy to help you troubleshoot this. Can you share the recipe you’re using? When you say “foamy and sugary,” do you mean it develops sugar crystals during the cooking process? Or something else? Assuming you are talking about sugar crystals, crystallization is a common problem in a lot of toffee/caramel recipes, and can usually be avoided with some recipe/behavior modifications. One thing that helps prevent crystallization is using either an acid (like a bit of lemon juice, vinegar, or baking soda) in the recipe, or an invert sugar like corn syrup or glucose syrup. If your recipe doesn’t contain any of these, crystallization is much more likely to occur. Additionally, I always recommend brushing down the sides of the pan with a wet pastry brush to prevent sugar crystals from clinging on to the sides and re-crystalizing the mix. And finally, avoid stirring the candy once it comes to a boil – agitating the mixture is much more likely to introduce sugar crystals.

      Re the toffee not browning, are you using a candy thermometer? What temperature are you cooking the sugar to? Most toffee recipes call for a very high temp (+/- 300F) and at that point sugar does start to caramelize – if you are cooking it this high and not seeing browning, what are you seeing? If you could provide me with a few more details I can hopefully be more specific with my suggestions.

      The last thing I will say is to look at the ingredients & equipment you’re using. Is your stove significantly different than what you had before? For example, could it be that the “medium” heat you used to use is different than the “medium” heat your current stove provides? As for ingredients, different areas sometimes carry different brands – are you using the same brands you used to? A change in butter or sugar brand could be the reason behind disappointing candy. For sugar, I always recommend C&H or Domino brand – they are made with cane sugar, unlike a lot of store brands that are made with beet sugar or a blend. I’ve found in my experience that beet sugar is a lot more unpredictable, but cane sugar gives me very consistent results. Similarly, with butter, some brands have a lot more water than others, which can really affect the texture of your candy. So take a look at ingredients and see if you can spot any changes there.

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