There's a lot of physical chemistry involved in making old fashioned fudge. The recipe calls for combining and boiling milk, bitter chocolate or cocoa, and sugar together until the temperature of the syrup reaches 238 degrees F (114o C), pouring the seething mixture into a bowl, cooling to 115 degrees F (46 degrees C), and then beating until the surface shine disappears. If you don't follow the cautions in the recipe -- wash down the sides of the pan with a wet pastry brush or cover the pan for a few minutes early in the cooking process; don't scrape the pan; don't disturb the candy until it's cooled; don't let anything, even a speck of dust, fall into the cooling syrup -- you are very likely to wind up with a coarse, gritty mass instead of creamy fudge.
Sugar dissolves far less readily in cold liquids than in hot. There is no way that two cups of sugar will dissolve in a cup of milk at room temperature. Heating the sugar and milk mixture allows the milk to dissolve more and more sugar, and by the time the mixture is boiling, all the sugar is dissolved. The general principle is that at a particular temperature, a given solvent (in this case, milk) can dissolve only so much of a particular solute (sugar). When the milk has dissolved all the sugar it can hold, and there is still some undissolved sugar left, the mixture is said to be saturated. The higher the temperature, the more concentrated the saturated solution becomes.
Water (and milk) boil at 212 degrees F (100 degrees C) at sea level, but the sugar changes that. In general, a solid dissolved in a liquid makes it harder for the liquid molecules to escape. Consequently, the solution has to be hotter for the liquid molecules to get away at the same rate, and the boiling point rises.
In our fudge, the rise in boiling temperature is an exact function of the amount of sugar in the solution. Consequently, we can use the temperature of the boiling syrup to tell when enough water has boiled away to give the syrup the right ratio of sugar to water. For fudge and similar creamy candies, the syrup should boil at a temperature 26 degrees F (14 degrees C) hotter than the boiling point of plain water.
Some of the initial water in the syrup has now boiled away. Because the sugar couldn't dissolve completely until the mixture was near boiling, the syrup reaches saturation very soon after it starts to cool. If you've done everything right, however, sugar does not come back out of solution. Instead, the syrup continues to cool as a supersaturated solution. The solid phase -- in this case, sugar -- cannot start to crystallize without something to serve as a pattern, or nucleus. However, if a single sugar crystal is present, the syrup will start to crystallize, the crystals will grow steadily as the syrup continues to cool, and the result will be very grainy fudge.
This is why most fudge recipes require that the sides of the pot be washed down early in the cooking process, either with a wet pastry brush or by putting the lid on the pan for about three minutes to remove any sugar crystals clinging to the container walls. It is also why the recipes specify that the sides and bottom of the pan should not be scraped into the bowl where the candy is to cool. There is too much chance of scraping in a stray sugar crystal.
As the cooling syrup gets more and more supersaturated, its tendency to crystallize becomes even stronger. Even a speck of dust can start the process if all the candy contains is sugar, milk, and chocolate. Using more than one kind of sugar can counter this tendency. Most fudge recipes contain either corn syrup (which contains glucose instead of the sucrose of table sugar) or cream of tartar (which breaks sucrose into glucose and fructose). The different sugars tend to interfere with each other's crystallization and minimize the chance that the candy will crystallize too soon. They must be used in moderation, however -- too much and the fudge will remain a thick syrup forever!
The final stage is stirring the syrup when it is lukewarm to promote crystallization all at once throughout the candy. Disturbing (stirring) a very supersaturated solution causes many crystals to form at once. Because they compete with each other for the dissolved sugar, none can grow very large. The result is the proper creamy texture of fudge and the change in appearance from shiny (supercooled liquid) to dull (a mass of very tiny crystals).
FAQs
When making fudge, heat and acid work together to convert sucrose – basic white sugar – into its two components, glucose and fructose. When these sugars are present, they prevent sucrose from turning into big sugar crystals.
What is the process of making fudge? ›
Commercial fudges are generally prepared by mixing milk, corn syrup (glucose), sugar, fat, a little salt, and suitable flavoring matter such as chocolate; cooking the resulting mixture to a temperature of about 235 F. to 245 F., while agitating the mix; cooling the mix to a temperature between 90 F.
What is the principle of fudge? ›
Principles of quality fudge
The key to creamy, luscious fudge is controlling crystal formation. If the sucrose (table sugar) crystals are small, the fudge will feel creamy and smooth on your tongue. But if the crystals are large, the fudge develops a crumbly, dry, or even coarse texture.
What type of solution is fudge? ›
Heating the syrup to a high temperature and then allowing it to cool, undisturbed, produces a supersaturated solution—this means that the solution contains more sugar molecules than would normally be possible at room temperature.
What makes fudge hard or soft? ›
If there is too much evaporation, when the cooking time is too long, there will not be enough water left in the fudge and it will be too hard. Conversely, if the cooking time is too brief and there is not enough evaporation, too much water will remain and the fudge will be too soft.
What is fudge explained? ›
fudge, creamy candy made with butter, sugar, milk, and usually chocolate, cooked together and beaten to a soft, smooth texture. Fudge may be thought of as having a consistency harder than that of fondant and softer than that of hard chocolate.
What is fudge technically? ›
Fudge is a dense, rich confection typically made with sugar, milk or cream, butter and chocolate or other flavorings. The base for fudge is boiled until it reaches the soft-ball stage (135 to 140 degrees F), then stirred or beaten as it cools to minimize the formation of sugar crystals.
What causes fudge to set? ›
The amount of time you cook fudge directly affects its firmness. Too little time and the water won't evaporate, causing the fudge to be soft. Conversely, cook it too long and fudge won't contain enough water, making it hard with a dry, crumbly texture.
What makes high quality fudge? ›
Candy that isn't cooked long enough will end up too soft; overcooking makes fudge crumbly or hard. High-quality fudge has many small crystals. If the process of crystallization begins too early, fewer crystals form and they become much larger.
What would cause fudge not to harden? ›
Homemade Fudge Doesn't Always Set
If your fudge doesn't firm up after a few hours, you either have too high an amount of liquid to sugar, or your mixture hasn't reached the soft-ball stage. Using a candy thermometer can help home cooks avoid this problem.
While you ultimately want crystals to form, it's important that they don't form too early. The key to successful, nongrainy fudge is in the cooling, not the cooking. The recipe calls for heating the ingredients to the soft-ball stage, or 234° F, then allowing it to cool undisturbed to approximately 110° F.
What is fudge terminology? ›
When fudge is a verb, it means to avoid straightforwardly answering a question or addressing a subject: "Just answer my question and don't fudge the issue!" Fudge is an American word from college slang meaning "a made-up story." Definitions of fudge. soft creamy candy. types: chocolate fudge.
How was fudge invented by mistake? ›
Fudge creation is often attributed to a happy accident in a confectionery experiment. The story goes that a batch of caramels went awry — “fudged,” in the parlance of the time — leading to the birth of this new sweet treat. This error resulted in the soft, creamy confection we now know as fudge.
How does fudge get its texture? ›
Small sugar crystals give you a smooth melt in the mouth texture. The secret to smooth fudge is to let the sugar syrup cool undisturbed until it reaches about 110°F and then beat it until no longer shiny.
What gives fudge its texture? ›
Tiny microcrystals in fudge are what give it its firm texture. The crystals are small enough, however, that they don't feel grainy on your tongue, but smooth. While you ultimately want crystals to form, it's important that they don't form too early.
Is making fudge considered baking? ›
Fudge is always a no-bake dessert and can be completely stove- and oven-free if you follow our method for how to make microwave fudge. That means it's a chocolate dessert idea that will keep your oven cool on even the steamiest days of summer.
