How to Read a Candy Thermometer
Never burn a pot of sugar again.
A candy thermometer is a handy tool to have in the kitchen, especially if you’re an avid baker and/or sugar enthusiast. Along with typical temperature measurements on your thermometer, you’ll notice phrases that alert bakers when their mixture of granulated sugar and water has reached the temperature that will yield a desired level of consistency in their final product. As the sugar continues to boil, the water evaporates and the sugar concentration increases, changing the density and pliability of the sugar.
Before the thermometer was a standard fixture in the kitchen, baker’s used the cold water test to determine stages of caramelizing sugar. A spoonful of sugar syrup is dropped in a cold water bath, and the shape that takes form in the water helped determine how concentrated the sugar was. If the sugar looked like stringy ropes, it was in the “thread” phase or if it formed a hard solid ball, it was in the “hard crack” phase. This is where the names of the stages designated on most candy thermometers originated.
Sugar starts boiling at 212 F° and will remain clear until 320 F°, when it begins to take on color. Within this temperature range, sugar transforms from a thin clear syrup, to a light caramel sauce. Various types of candy begin to take form at the varying stages within this range as well. You can make soft candies like caramels on the lower temperature scale, or hard candies like lollipops at the higher end. There are factors other than the temperature that affect your sugar syrup such as sugar-water ratio, cookware material, cookware color, and how evenly your cookware distributes heat; therefore, the temperatures are divided into ranges.
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When your mixture had reached the desired temperature, it is recommended to suspend cooking any further. Simple syrup is created as soon as the sugar starts to boil, you can remove it from the heat at this point and mix it into your favorite cocktails. Do keep in mind that when you’re dealing with boiling-hot sugar, you should never stick your fingers in the pot or taste the syrup at any time while it is hot. The sugar retains temperatures hot enough to leave a serious burn. You also want to avoid walking away from a pot of boiling sugar—your sugar solution can burn in a matter of seconds. All of that said, once you familiarize yourself with the process of working with sugar, you’ll quickly develop a better eye for the changes in your sugar as it boils. It’s not as scary as it seems, I promise.
Here is the breakdown of how to read and understand the temperature ranges and the sugar concentration indicated on your candy thermometer.
(230° to 235°F/106° to 112°C)
Sugar concentration: 80%
Thread is the early stage of sugar syrup that forms thin strands when drizzled and cooled. The syrup can be used to make meringue and syrups in this stage.
(235° to 240°F/112° to 16°C)
Sugar concentration: 85%
At the soft ball stage, the sugar syrup is viscous and when dropped in water, it forms a ball but quickly loses it shape when taken out of the water. Sugar syrup at this stage is right for fondant, fudge, pralines, and penuche.
(245° to 250F°/118° to 120°C)
Sugar concentration: 87%
The sugar syrup is very tacky and thick this point. If you drop it in water, it will form a loose ball, but will be sticky to the touch. Caramel candies are cooked to this stage, and the sugar syrup’s reaction with cream gives the sweet treat its signature color.
(250° to 265°F/121° to 130°C)
Sugar concentration: 90%
At the hardball stage your sugar forms a ball and holds its shape when dropped in cold water with some resistance and buoyancy. The textures of nougat, marshmallow, gummy candies are created at this stage.
(270° to 290°F/132° to 143°C)
Sugar concentration: 95%
Soft crack is the stage when sugar is pliable and can be pulled with your fingers. Chewy, sticky candies like taffy, butterscotch, and toffee are made in this phase.
(300° to 310°F/149° to 154°C)
Sugar concentration: 94%
Lollipops, brittles, and hard candies are created at the hard crack stage. When the sugar syrup is dropped in cold water it will completely solidify.
(320° to 335°F/160° to 170°C)
Sugar concentration: 100%
The sugar mixture starts to break down and takes on a light brown color. This is the temperature where caramel develops a bright nutty flavor. When your sugar starts to brown, do not walk away from the pot. The sugar heats faster and burns easily at this point. If you want a golden caramel sauce, you can begin to remove it from the heat at this temperature range.
(340° to 350°F/171°C)
Sugar concentration: 100%
Here is the sweet spot to add your heavy cream to the sugar syrup and stop the cooking process to make a deeply colored, robustly flavored caramel sauce. Remove your pot from the heat and do not proceed to cook further.
You have burnt your sugar syrup into a black, sticky disaster. It’s best to allow the sugar to cool, throw away, and start over. (Pro-tip: Boiling water can help remove the burnt-on caramel from your pan.) There is nothing to salvage. Nice try, but try again.