Autumn is coming, which means marshmallow season is just around the corner. Whether you toast these fluffy candies over a campfire, float them in a mug of hot cocoa, or simply eat them plain, ’mallows are a quintessential fall and winter treat. A little patience and a whole lot of science goes into making these confections—and you don’t even need a candy thermometer to whip them up from scratch.
Sugar science 101
Understanding the marshmallow-making process requires some elementary knowledge of how sugar changes during candymaking, as a major component of delicious, fluffy marshmallows is a thick sugar syrup. From the thread stage all the way up to the hard crack stage, the consistency of this sweet goop is vitally important to the end product.
Most home marshmallow-makers aim for the soft ball or firm ball stages, which refer to the consistency a small dollop of boiled sugar exhibits when dropped into a cup of cold water. The New York Times, Food Network, Alton Brown, and Epicurious all suggest heating your sugar to 240 degrees Fahrenheit—the upper end of the soft ball stage. Other recipes say a little hotter is better, recommending the firm ball stage at 242 to 245 degrees. Some candymaking guides even place marshmallows in the hard ball category of 250 to 265 degrees.
All that can be intimidating and stressful, and not everyone has a candy thermometer at hand. Our recipe, however, forgoes the precise temperature monitoring that many recipes call for. Instead, we’ll use timing and a real-time consistency test to check that our sugar is ready to whip into marshmallows.
Warning: Boiled sugar is tricky to work with—it’s sticky, changes states quickly, and can cause nasty burns. Never leave it unattended while it’s heating, and keep a bowl of cold water nearby in case any gets on your bare skin.
- Time: 45 minutes, plus 4-6 hours to set
- Cost: $10
- Difficulty: Hard
- 2 cups of granulated white sugar
- ½ cup of light corn syrup
- 3 quarter-ounce packets of unflavored gelatin powder (around 7 teaspoons)
- 1 tablespoon of vanilla extract
- Pinch of salt
- ½ cup of powdered sugar
- Cooking pot
- Large bowl
- Small dish
- Electric mixer with a whisk attachment
- Baking pan
- Plastic wrap
- Sharp knife
1. Line your baking pan with buttered plastic wrap. This may sound strange, but you’re about to create an incredibly sticky substance. Everything that touches your marshmallows, including tools and utensils, should be greased to prevent sticking.
2. Pour a half-cup of cold water into your mixing bowl, then sprinkle the gelatin powder into it. Don’t stir—just leave the gelatin to soak and “bloom” for around 10 minutes while you complete steps 3 through 6.
3. Combine a half-cup of water, the corn syrup, and the granulated sugar in a cooking pot. Whisk these ingredients together, then put your utensils aside and place a small dish of cool water next to your cooking surface.
4. Bring the sugar mixture to a boil over medium heat. Resist the urge to stir it—any unnecessary agitation can disrupt the boiling process and coax the sugar back into a solid form. Instead, simply swirl the cooking pot occasionally to distribute the heat.
- Pro tip: If you see sugar crystals forming around the edges of the pot as the mixture heats up, place a lid on the pot for a minute or two. The condensation that builds up under the lid will drip back down the sides of the pot, washing these crystals back into the mixture below.
5. Cover the mixture with a lid and let it boil for 60 seconds without stirring.
6. Reduce the heat and check your consistency. Taking care not to disturb the boiling sugar mixture too much, scoop up a small amount with a spoon and drop it into your dish of water. The syrup should form into a soft, squishy ball with a consistency similar to a chewy caramel candy. If it does, move on to step 7. If it doesn’t, check below for how to proceed:
- If the syrup dissolves into the water or forms thin, loose threads that can’t be easily gathered into a ball, it’s in the thread stage. Boil your sugar on medium heat for 1 minute longer and perform this test again with a fresh dish of water.
- If the syrup forms a hard, tacky clump or thick threads that can’t be easily formed into a ball, you’ve boiled the mixture for too long. Add a small amount of water and bring the mixture to a boil again, then redo the test with a fresh dish of water.
- If the syrup has taken on an orange or brown color without a burnt smell, you’ve made caramel. Pat yourself on the back and dip some apple slices in it, then start the sugar mixture from scratch.
- If the syrup begins to look or smell burnt, it probably is. Turn off the heat, soak your cooking pot—inside and out—in hot water until everything is cool enough to handle, and wash the burnt sugar out. Then, start the sugar mixture from scratch.
7. Wait for the bubbles to subside, then pour the sugar syrup into your mixing bowl and mix on medium-low speed. If possible, let the syrup run down the inside of the mixer’s bowl before it comes into contact with the gelatin below—this will cool it down a bit.
8. Add the pinch of salt and increase the mixer speed to medium-high.
9. Beat the marshmallow mixture for 10 to 12 minutes. It should nearly triple in size and acquire the white, fluffy consistency we all know and love. It will also cool to just above room temperature during this time.
- Note: You can do this with a handheld electric mixer, but your arms will thank you if you use a stand mixer.
10. Add the vanilla extract and beat until just combined.
11. Pour your marshmallow “dough” into the prepared pan and let it rest for 4 to 6 hours. Cover it with another buttered sheet of plastic wrap to protect the surface. Don’t put it in the fridge or freezer to speed up the cooling process—this will lead to tough marshmallows.
12. Slice and dust your finished marshmallows. Use a sharp knife greased with butter to cleanly slice the finished marshmallows. Powder them generously on all sides with powdered sugar. They are now ready to gift, roast, eat, and enjoy.