The simple reason is that your candy has too much moisture. This issue might be caused by one or more things. It is critical to cook all of the water out of the sugar/corn syrup/water combination while producing hard candy. The longer you cook it, the less moisture there will be and the clearer your candy will be.
Start with a ratio of 1:1 sugar to corn syrup. Use as much sugar as necessary until the mixture reaches 250 degrees F (121 C). Do not go above this temperature because it will cause the candy to burn. Once the mixture reaches this temperature, slowly add in enough water for the liquid to become opaque. You should only need about 3 tablespoons of water per 2 cups of sugar. Let the mixture cool completely before proceeding further.
Now, heat the mixture in a large saucepan over low heat until it reaches 110 degrees F (43 C). While still hot, drop small amounts of the mixture onto a plate covered in powdered sugar. If the mixture is clear after cooling, it will be fine for selling at room temperature. Otherwise, refrigerate or freeze the candy before serving.
Hard candies usually have a grainy texture due to the sugar crystallizing during cooking. However, since we are making something that will be sold at a grocery store, we do not want to damage the product so do not rush the heating process.
What's the deal with my hard candy becoming mushy and sticky? If any sugar granules remain, they will continue to dissolve in the liquid mass causing the mixture to become sloppy and gummy.
To fix this, reduce the temperature of the cooking process or increase the amount of time you cook the mixture slowly. Either way, you want to make sure that none of the water remains in the mixture.
If you're making marshmallows, it's important to remove the pan from the heat before the mixture reaches 160 degrees F because once that temperature is reached, the sugar will begin to melt immediately, causing the mixture to turn into a syrupy mess - not what you are looking for!
For hard candy and caramels, cooking the mixture until it is slightly darker than honey colored means that the water has been driven off and the remaining ingredients are completely dissolved into a single mass. If you over-cook them, the result will be a brittle candy that is difficult to chew. If you under-cook them, the mixture won't solidify properly.
Humidity is a hard candy's worst enemy. It will harden into a sticky goo. I'd put a few pieces in an airtight jar with some dry rice (or, better yet, silica gel packets) and see if it helps. Instead of powdered sugar, consider lightly coating the candies with cornstarch. This will help keep them from sticking to your teeth.
The soda's carbon dioxide bubbles were adhering to the sweets, and when enough lighter-than-soda bubbles gathered on a particular candy, they should have pushed it up through the soda. When the carbon dioxide bubbles reach the top of the drink, they may escape into the air, causing the candy to sink once again. This goes on forever unless someone pulls the bottle out of the ice cream.
In fact, this is how most soft drinks are made. The ingredients are mixed together, then carbonated water is added until the mixture reaches the correct level of fizziness. The carbonation will keep increasing as the beverage sits in the bottle or can, so don't worry about it getting too bubbly when you first pour it off of the mixer bag.
Some people think that if a piece of candy is inside a bottle of soda, then it must be part of the label. This is not true. The candy could have come from anywhere, even if it looks like it came with the label. Sometimes manufacturers put extra pieces of candy in their products as advertising gimmicks. Other times, they use candy because it's cheap ingredient filler.
People also sometimes assume that if a piece of candy is inside a bottle of soda, then it must be harmful to eat. The FDA does not test bottles of soda for toxic substances such as arsenic or lead. They only check to make sure that the product labels are accurate about what's in them.
Instead, we must employ heat. You may compel more sugar to dissolve by increasing the temperature of the liquid. This idea is critical in the production of sweets. It results in the formation of a supersaturated liquid. As the name suggests, a supersaturated solution is one that has more molecules of solute than there are available sites for them to bind to. If you increase the temperature enough, all of the sites will be filled up, and no more molecules will dissolve.
In other words, if you heat sugar water until it reaches 140 degrees F (60 degrees C), it will no longer dissolve any more sugar particles. Instead, all of the sites on each molecule are occupied, and no more can dissolve. Heating sugar creates a state of high concentration that prevents further dissolution. This is why cooking sugar-based foods like cookies or candies requires very high temperatures so as not to disturb this state.
At lower temperatures, some of the molecules would still be able to dissolve into their respective components, but at a very slow rate. For example, one study showed that heating caramel at 150 degrees F (66 degrees C) only reduced its viscosity by about 20 percent after three hours. By comparison, boiling it for the same time period reduced its viscosity by nearly 100 percent.
When manufacturing sugar-based candy or syrup, the batch can "sugar," or more precisely, crystallize, at any point during the heating process. This produces steam, which melts any sugar crystals that may have stuck to the pan's edges. Unless otherwise specified in the recipe, do not stir the syrup after it begins to boil. This will only cause the crystalized sugar to break up further.
If your syrup is very sweet, it may not need any additional sugar added to it. However, if it is slightly undercooked (140 degrees F or 60 degrees C), then a few tablespoons of sugar per cup of syrup will help it come together as a clear liquid. The sugar also acts as a natural anti-foaming agent.
Syrups used for making candies require additional sugar because they are generally cooked longer than syrups used for making jams or jellies. For example, most candy bars are cooked until they reach 240 degrees F (115 degrees C), while most jelly jars are only heated through once they reach 220 degrees F (105 degrees C). Cooking sugar for so long destroys some of its nutrients but also greatly increases its sweetness. When cooking less-sweet ingredients like fruit in sugar, add them toward the end of the cooking time so they don't lose their color or flavor.
Cooking sugar also causes certain minerals to be released from some types of clay pans. These include calcium and magnesium, which are needed for healthy teeth and bones, respectively.