Two days before Christmas, Chris emailed me a recipe from a co-worker for something called “Glass Candy.” This co-worker had brought some to a work party and he thought it would be something I’d like to make. I’d never tried making candy before, but it looked pretty easy.
I started making the candy after lunch on Christmas Eve. First, I coated a cookie sheet with powdered sugar. Then I combined sugar, water, and Karo syrup in a pot. Then I read the next step: “Boil until the mixture reaches a hard crack about 300 degrees.”
No problem. I had a thermometer. But as I stood at my stove, the sugar mixture already heating to a bubbling syrup, and looked down at my thermometer, I was dismayed to see that it had a maximum temperature reading of 220 degrees. What could I do?
I considered the reference to a “hard crack.”Was “hard crack” an actual candymaking term? I had thought it was just a description chosen by the writer of the recipe, but if were a “technical” term used in candy making, perhaps it held the solution to my problem.
I flipped open my new 2006 edition of The Joy of Cooking to the chapter about candy, where I found a description of how to check the readiness of sugar syrup without a thermometer, using the cold water test. It was followed by illustrations.
Apparently the hard-crack stage occurs between 300 and 310 degrees Fahrenheit. Toffee, nut brittles, and lollipops are all cooked to the hard-crack stage. The hard-crack stage is the highest temperature a cook is likely to see specified in a candy recipe. At these temperatures, there is almost no water left in the syrup.
To perform a cold water test, you drop a little of the molten syrup in cold water. At the hard-crack stage, it will form hard, brittle threads that break when bent.
So! I could check the readiness of the candy without an accurate thermometer.
But, even with an answer in hand, I was nervous. I had never tried anything like this before, and I had no one to show me how to do it right—just a set of illustrations and some reading done on the spot while the pot was boiling.
I used my thermometer to tell me when the mixture has passed 220 degrees. Then I began testing the sugar syrup by scooping a small amount of it on a metal spoon (that I warmed in a nearby jar of warm water) and dropping it into a small bowl of cold water. The first time I did this, the syrup formed a liquid-y thread in the cold water but did not ball up or harden. My cookbook told me that this is called the thread stage.
I tested the syrup several more times. Each time it did something different when dropped in the cold water:
- Formed a soft, flexible ball that flattened when I removed it from the water (soft-ball stage, 235° F–240° F)
- Formed a firm ball that remained malleable when removed from the water and flattened when squeezed (firm-ball stage, 245° F–250° F)
- Formed thick, ropy threads as it dripped from the spoon into the water, then formed a hard ball in the water and did not flatten when removed, although it could be squashed (hard-ball stage, 250° F–265° F)
- Formed threads and not a ball in the water. When removed from the water, the threads were flexible, not brittle, and bent before breaking (soft-crack stage, 270° F–290° F)
- Formed hard, brittle threads that, once removed from the water, broke when bent (hard-crack stage, 300° F–310° F)
When the syrup reached the last stage, I immediately added several drops of blue food coloring and about two splashes of anise flavoring. (I was so nervous that I forgot to measure the anise I used, but I’d estimate I used a couple of teaspoons.) Then I poured the mixture onto the prepared cookie sheet and let it cool completely.
When the sheet of candy was cooled to the touch, Chris and I shattered it with the edge of a meat tenderizer and placed the pieces in a glass dish. The candy looked just like pieces of blue glass and tasted like licorice.
Making glass candy for the first time was not as easy as it looked. It’s probably just as well that I didn’t know how nerve-wracking it would be, because I might not have tried it. Now, on the other side of my first candy adventure, I can say that the science experiment of progressing through the stages of cooking sugar syrup using the cold water test was pretty darn fascinating.
I’m looking forward to trying candy again. And I won’t have to do it without a clue as to the actual temperature next time, because my mother-in-law just gave me an old candy thermometer to use, one that most definitely reads up to 300 degrees.
2 cups sugar
1 cup water
¾ cup Karo syrup
Flavoring (peppermint, anise, etc.)
Prepare a cookie sheet by coating with powdered sugar.
Combine in a pot sugar, water, and Karo syrup. Boil until the mixture reaches a hard crack about 300 degrees.
(Note: if using the cold water test to check the syrup’s readiness, look for the syrup to form, after being dropped in the cold water, hard, brittle threads that break when bent. CAUTION: To avoid burns, allow the syrup to cool in the cold water for a few moments before touching it.)
Quickly stir in desired flavor and food coloring. Note: it probably will take twice as much as you think it should.
Pour onto prepared cookie sheet. Allow to cool for a bit. If desired, sprinkle top with powdered sugar. (I liked it without the powdered sugar on top.) Allow to cool completely.
Break apart (the edge of a meat tenderizer works well) and enjoy!