How to Prevent Sugar from Crystallizing

Co-authored by Kyle Hall

Last Updated: August 25, 2021 References

Dessert and candy recipes often require cooking sugar into syrup. It can be tricky to get sugar syrup right, and you might find yourself getting a grainy, thick, or hard mixture instead of the result you want.^{[1]
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How do sugar crystals form?

Sugar crystals form after heated sugar molecules cool down into a hard structure. Sugar will latch onto other particulates like burnt caramel or dirt, so once some sugar crystalizes, it’s likely the crystallization will spread.^{[2]
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- Use a wet pastry brush to scrape off any crystals you see forming on the pot to prevent more buildup.^{[3]
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- Some candy and desserts like fondant and fudge depend on crystallization, so check your individual recipe to make sure you’re getting the right level of crystallization.

Why is my sugar crystallizing?

Unclean pots and pans, hard water, excessive stirring, and impure sugar can all cause sugar to crystallize. Sugar will latch onto particulates like minerals in the water or even foreign objects like your stirring spoon.^{[4]
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- Thoroughly dry your pots and pans before using them to prevent sugar from clumping in water droplets.
- If you have water with a high mineral content (“hard water”), invest in a water filter or purifying pitcher.^{[5]
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- To avoid impure sugar, use a clean scoop when you measure out the sugar. For instance, if you scoop flour with one measuring spoon, don’t re-use the spoon for sugar.^{[6]
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How can I prevent sugar from crystallizing?

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Instead of bringing the sugar-water mixture to a boil, only bring the mixture to a simmer. Then, partially cover the pan/pot and continue simmering for 10 minutes. The lower heat allows the sugar to dissolve more evenly.^{[7]
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- As an alternative solution, before cooking, add corn syrup or a mild acid like lemon juice, vinegar, or cream of tartar to break up crystallization. This method may still result in some crystallization after 48 hours.
- For the sugar-water ratio of 2:1 needed for rich syrup, add ¼ teaspoon of either corn syrup or a mild acid. Adding more of the syrup or acid will affect the flavor noticeably.
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Stirring or bumping the pot can result in sugar clumping together and hardening into crystals. If you’re making syrup with water, stir the sugar into the water to fully dissolve it before you add heat.^{[8]
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- Use a clean spoon every time you need to stir. The same goes for candy thermometers and any utensils. Particulates on the dirty equipment will result in crystallization.

How do I fix crystallized sugar?

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If your sugar has already crystallized in a pot or pan, add more water and return the mixture to a boil to dissolve the crystals. Use a small amount of water (the exact amount doesn’t matter because it will evaporate).^{[9]
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- Start with a low heat to ensure the sugar doesn’t burn. Once the crystals have dissolved, you can refer back to the original recipe for heat settings.
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If your crystallized sugar is already in a plastic container (particularly with honey or maple syrup), set the container in a bowl of warm water.
- If the sugar crystallization is in a glass jar, don’t set the jar in hot water or it may shatter. Scrape the contents into a pot and use low stovetop heat to break up the crystallization.^{[10]
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How do I clean crystalized sugar off my pans?

Add enough water to cover the hardened sugar and bring it to a boil. The boiling water will break up the crystalized sugar.^{[11]
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- To keep your pots and pans crystal-free, partially cover the pot while you’re cooking the sugar. The steam will make the pot slippery enough to prevent crystals from adhering to the sides.