How to Heat Treat Flour to Make it Safer

Want to enjoy your favorite no-bake dessert but don’t want to take the risk of eating raw flour? It’s not foolproof, but heat-treating flour may help make your flour safer to consume. Even better, it’s versatile—you can heat treat flour in an oven, microwave, or skillet—and it only takes a few minutes. We’re here with everything you need to know about heat-treating flour, plus we have tips on sifting and storing your flour from baker Jessica Banh and professional chef Ollie George Cigliano.

How do you heat-treat flour?

Baker Craig Watson says to spread the flour in an even layer about ¾ in (1.9 cm) thick on a baking sheet lined with parchment paper. Bake the flour for about 6 minutes at 400 °F (204 °C), then stir and check with an instant-read thermometer to ensure the flour has reached 165 °F (74 °C).

Section 1 of 7:

Heat Treating Flour in an Oven

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Spread the flour in a thin layer on a parchment paper-lined baking sheet. Preheat your oven to 400 °F (204 °C) and spread a piece of parchment paper across a baking sheet. Measure out the flour you want to heat treat and use a spatula to spread it out in an even layer on the baking sheet. To ensure the flour heats through, only use enough to make a ³⁄₄ in (1.9 cm) layer across the baking sheet.^{[1]
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- Baking tip: Use a little more flour than you’ll need for your recipe. Even with parchment paper, some of the flour might stick to the bottom of the pan. Don’t try to scrape off any of the flour that’s stuck to the pan—it will be clumpy and may taste burnt.^{[2]
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Bake the flour for 6 minutes at 400 °F (204 °C). Put the baking sheet in the oven and set a timer. After 6 minutes, take out the baking sheet and use your spatula to stir the flour.^{[3]
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- Stirring the flour will help ensure that the heat is distributed evenly.
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Check the temperature with an instant-read thermometer. If any spots read less than 165 °F (74 °C), put the baking sheet back in for two minutes at a time until the flour reaches the target temperature.^{[4]
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- Safety tip: Checking the flour in several places will help ensure it’s all heated evenly. Make sure every section reads at least 165 °F (74 °C) for the safest results.

Section 2 of 7:

Heat Treating Flour in the Microwave

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Pour your flour into a microwave-safe bowl. As long as you’re using a microwave-safe bowl, you can heat-treat as much or as little flour as you’d like. If you use more than the recipe calls for, store it in an airtight container until you need it. Just note that if you use a lot of flour, you might need to heat it a little longer to bring it up to temperature.^{[5]
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- Not sure how to tell if a container is safe for the microwave? Check for a stamp on the bottom that looks like 2–3 wavy lines. It may also say “microwave safe” on the bottom.
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Microwave the bowl on high for 30 secs., then stir and repeat as needed. When the microwave stops, stir the flour well with a heat-safe spoon or spatula. After you stir, use an instant-read thermometer to check the temperature of the flour. Keep microwaving in 30-second intervals until the thermometer reads 165 °F (74 °C).^{[6]
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- Safety tip: Test the temperature of the flour in several places—if any readings show less than 165 °F (74 °C), put the flour back in for another 30 seconds.

Section 3 of 7:

Heat Treating Flour in a Skillet

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Stir the flour constantly so it doesn’t scorch. After about 3 minutes, take the pan off the element, stir the flour again, and check the temperature with an instant-read thermometer. If every reading is at least 165 °F (74 °C), let the flour cool, then use it.^{[7]
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When and why should you heat treat flour?

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Heat treat flour to reduce bacteria when you want to make no-bake treats. Because flour can contain bacteria like salmonella and E. coli, you shouldn’t consume it raw. Heat-treating may make it safer to eat, so it’s a better choice for recipes like edible cookie dough and no-bake cakes. It may also make homemade play doughs safer for children.
- Safety info: There’s some concern that heat-treatingheat treating flour in the home won’t sufficiently kill all harmful bacteria, so it may be safer to avoid eating raw flour if you’re immunocompromised or otherwise vulnerable to illness, even if it’s heat-treatedheat treated.^{[8]
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Section 5 of 7:

Using & Storing Heat-Treated Flour

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Using the flour before it’s cooled could affect the finished dish’s temperature and texture, so wait about 30 minutes before you add it to your recipe. If you’re in a hurry, put the bowl in the fridge for a few minutes, stirring occasionally until the flour is evenly cooled.^{[9]
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Heat-treating flour can cause lumps. To properly sift flour, Banh recommends “passing it through a sieve to knock out any clumps and so it will be fine and fluffy.”^{[10]
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Jessica Banh
Pastry Chef

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Store the flour in an airtight container for up to 10 months. Cigliano says, “Store your flour in airtight plasticware or a glass mason jar. That will keep it fresh and pest-free for up to 10 months.”^{[11]
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Ollie George Cigliano
Private Chef & Food Educator

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- Cigliano adds, “If you vacuum seal the flour, it can last for up to two years.”^{[12]
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  Ollie George Cigliano
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Section 6 of 7:

What is heat-treated flour?

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Uncooked flour can harbor bacteria like salmonella and E. coli. These bacteria are normally destroyed when the flour is cooked. If you’re planning to add flour to a no-bake recipe, heat-treating the flour first may help kill these bacteria, making it safer to eat.

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FAQs

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Can you heat-treat cake mix? Yes, you can heat-treat cake mix using the exact same method you’d use to heat-treat flour.
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Can you heat treat flour in an air fryer? No, the air will blow the flour around. This will make a big mess and could even be a fire hazard.
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Can you heat treat flour in advance? Yes, you can heat-treat flour in advance. According to Cigliano, if you properly store flour, it can stay fresh for up to 10 months, or longer if you vacuum seal it.^{[13]
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Ollie George Cigliano
Private Chef & Food Educator

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Can you heat treat flour without a thermometer? To ensure your flour is heated to a safe temperature, it’s best to use an instant-read thermometer. They’re fairly inexpensive and available online or at any big-box store.