Science of Candy: What's Special About Fudge? | Exploratorium (2024)

What’s special about fudge?

Science of Candy: What's Special About Fudge? | Exploratorium (1) Fudge is one of the rare exceptions to the rule that sugar crystals are not desirable in candy. 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. 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. If you stir during this cooling phase, you increase the likelihood that seed crystals will form too soon.

Science of Candy: What's Special About Fudge? | Exploratorium (2) A seed crystal is a surface that sucrose molecules (that's the sugar) can begin to attach themselves to—it could be a few sucrose molecules stuck together, a piece of dust, or even a little air bubble. Once a seed crystal forms, it grows bigger and bigger as the fudge cools. A lot of big crystals in fudge makes it grainy.

By letting the fudge cool without stirring, you avoid creating seed crystals. Stirring would help sucrose molecules "find" one another and start forming crystals. Stirring also introduces air, dust, and small dried bits from the walls of the saucepan—all potential seeds for crystal formation.

When the fudge has cooled to about 110° F, you want to start the crystallization process. You start to stir, and keep stirring, until the candy becomes thick. The more you stir, the more crystal seeds you get. But instead of getting a few huge crystals (and grainy candy), you get lots and lots of tiny crystals, which make for thick, smooth candy.

There are two other candies that deliberately employ sugar crystals. One is fondant, a wetter version of fudge that you find inside soft-center chocolates. The other is rock candy, for which a sugar solution is left for days to form enormous crystals.

Think you get it? Try making fudge or rock candy yourself!

Science of Candy: What's Special About Fudge? | Exploratorium (2024)

FAQs

Science of Candy: What's Special About Fudge? | Exploratorium? ›

Fudge is one of the rare exceptions to the rule that sugar crystals are not desirable in candy. 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.

How does fudge relate to chemistry? ›

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 science behind candy making? ›

Heating up the solution forces the sucrose molecules to break up and caramelize. But when we do that, the sugar molecules really want to crystallize back into their solid form. Candy-makers use that crystallization process, and some strategic interference, to create the candies that we know and love.

What is the secret to good fudge? ›

Valuable tips for successful fudge
  • Don't stir during cooking. Fudge can be cooked on the stove or in the microwave. ...
  • Avoid crystallization. During cooking, sugar crystals can stick to the sides of the pan. ...
  • Let cool before beating. After being cooked, the sugar must crystallize again to create fudge. ...
  • Beat the mixture.

Why must fudge be vigorously beaten after it has cooled to a specific temperature? ›

Beating after cooling

This fudge cooled until it reached 43 to 45 °C (109 to 113 °F) before being beaten. It has a smooth and creamy texture, just how we like it. Here's why: syrup becomes quite viscous (thick) while cooling, and this slows the movement of sugar molecules.

What makes fudge special? ›

Fudge is one of the rare exceptions to the rule that sugar crystals are not desirable in candy. 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.

What is the principle of fudge? ›

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).

How to make fudge more solid? ›

How do you fix fudge that is too soft? Bring the fudge back to a boil with 1–2 US tbsp (15–30 ml) of cream. If your fudge is soft or runny, it probably didn't come up to a high enough temperature while it was cooking. Put it back into the saucepan and add 1–2 US tbsp (15–30 ml) of 35% fat whipping cream.

Why is my 3 ingredient fudge not setting? ›

Why won't my 3 ingredient fudge set? This often happens when the condensed milk and chocolate chip mixture isn't hot enough to start.

What would cause fudge not to harden? ›

The main reason is that your Fudge has not reached the optimum temperature. If your mixture only reaches 110 or 112 degrees Celsius it will always be soft. That's why we recommend investing in a sugar thermometer. Another reason your Fudge is not setting is that the ratio of liquid to sugar is too high.

Why do you use a wooden spoon for fudge? ›

In his book On Food and Cooking, food scientist Harold McGee writes, “A metal spoon can induce crystallization by conducting heat away from local areas of the syrup, cooling them and so leaving them supersaturated [causing crystallization].” He recommends using a wooden spoon, which doesn't conduct heat.

Why can't you make fudge when it's raining? ›

As strange as it sounds, it is a fact that weather affects fudge making. This is because when the weather is damper with an increased humidity level your Homemade Fudge Recipe will take longer to boil.

What happens if you boil fudge too long? ›

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.

How is chocolate related to chemistry? ›

The main flavor compounds in chocolate are polyphenols, present in raw cocoa bean and going through various forms during production, and pyrazines formed during production, followed by aldehydes, ketones, and esters.

How is food related to chemistry? ›

Chemical substances can play an important role in food production and preservation. Food additives can, for example, prolong the shelf life of foods; others, such as colours, can make food more attractive. Flavourings are used to make food tastier.

What's chocolate and how does its chemistry inspire such cravings? ›

Chocolate is the richest natural source of theobromine, but coffee and tea contain some of it too. Theobromine chemically resembles caffeine and has a similar stimulating effect on our brains. The combination of theobromine and caffeine found in chocolate is believed to create the small lift we feel after eating it.

Is fudge a mixture? ›

Although fudge often contains chocolate, fudge is not the same as chocolate. Chocolate is a mix of cocoa solids, cocoa butter and sometimes sugar and other flavorings and is hard and brittle. Fudge is a mixture of sugar, dairy and flavorings that is cooked and cooled to form a smooth, semi-soft confection.

Top Articles
Latest Posts
Article information

Author: Tuan Roob DDS

Last Updated:

Views: 6338

Rating: 4.1 / 5 (42 voted)

Reviews: 81% of readers found this page helpful

Author information

Name: Tuan Roob DDS

Birthday: 1999-11-20

Address: Suite 592 642 Pfannerstill Island, South Keila, LA 74970-3076

Phone: +9617721773649

Job: Marketing Producer

Hobby: Skydiving, Flag Football, Knitting, Running, Lego building, Hunting, Juggling

Introduction: My name is Tuan Roob DDS, I am a friendly, good, energetic, faithful, fantastic, gentle, enchanting person who loves writing and wants to share my knowledge and understanding with you.