Candy Sugar Stages: Soft Ball to Hard Crack

Candy recipes are unusually bossy about temperature. Where a stew is happy anywhere near a simmer, a caramel recipe insists on 245 degrees, not 240 and not 250. That precision is not fussiness. With sugar, temperature is a direct readout of something you cannot see, and a few degrees genuinely changes a soft chewy caramel into a hard candy. Once you understand what the thermometer is actually telling you, the named stages stop being mysterious kitchen jargon.

Temperature Is a Concentration Gauge

Start with a pot of sugar dissolved in water. As you boil it, the water steadily evaporates while the sugar stays behind, so the syrup grows more and more concentrated. Here is the key idea: the more concentrated the sugar, the higher the boiling temperature. Pure water boils at 212 degrees, but as sugar takes over the syrup, the boiling point climbs.

That means the temperature on your thermometer is really a measurement of how much water is left and how concentrated the sugar has become. When a recipe says 240 degrees, it is telling you to boil off water until the syrup reaches a specific sugar concentration. You cannot eyeball concentration, but you can read it precisely off a thermometer, which is why candy making leans on one so heavily. For more on how sugar behaves under heat, see our guide to sugar in baking .

What the Stages Mean

The traditional stage names come from an old test: drop a bit of hot syrup into cold water and see what it forms. Each name marks a concentration and the texture it produces when cooled.

The thread stage, around 230 degrees, is still mostly syrup and forms thin threads. Soft ball, around 235 to 240 degrees, forms a ball that flattens when you pick it up, the texture behind fudge, fondant, and many caramels. Firm ball, near 245 to 250 degrees, holds its shape more, used for firmer caramels and marshmallows. Hard ball, around 250 to 265 degrees, forms a chewy, holdable ball and shows up in nougat and divinity.

Push higher and the syrup starts giving up its chewiness for brittleness. Soft crack, around 270 to 290 degrees, forms threads that bend a little before snapping, the stage for taffy. Hard crack, around 300 to 310 degrees, forms threads that snap cleanly and shatter, which is what gives brittle, toffee, and lollipops their glassy, breakable texture. Beyond that the sugar begins to brown and break down into caramel , a different reaction entirely.

Why Firmer Means Hotter

The progression from soft and chewy to hard and brittle follows directly from water content. At soft ball, there is still enough water in the cooled candy to keep it pliable and chewy. As you boil to higher temperatures, you drive off more water, and the cooled candy has less and less moisture to soften it. By hard crack, almost all the water is gone, leaving nearly pure sugar that cools into a hard, glassy solid.

So the texture you want dictates the temperature you cook to, and the temperature dictates how much water you boil away. Chewy candies stop early with water still present. Hard candies go all the way to nearly dry. There is no separate ingredient that makes brittle brittle. It is the same sugar, just cooked to a higher concentration.

Precision and a Few Practical Notes

Because the stages are separated by only a handful of degrees, accuracy matters. Calibrate your thermometer by checking it in plain boiling water before you start, since boiling water should read 212 degrees at sea level and any error tells you how far off your thermometer runs. If you bake at altitude, remember that water boils lower up there, so your stage temperatures shift down accordingly, a direct cousin of the issue in our high-altitude baking guide.

Two habits save batches. Pull the pot off the heat the moment you reach your target, because a hot syrup keeps climbing from residual heat and can blow past your stage in seconds. And work quickly once you are there, since the syrup begins setting as it cools. Respect the thermometer, know your target stage before you light the burner, and candy making turns from a temperamental gamble into a reliable, repeatable bit of edible chemistry.