Machines called refiners roll cocoa liquor until it is extremely fine, and the aim is particles of about 0.001 inch, or 0.00254 centimeters. A gauge called a Grind-o-meter can check how fine the grind is. Conching is a long stirring and heating step that follows roasting and grinding, and it can last from three hours to three days, although longer is not always better. Conching drives off water, acid and harsh flavors, and it breaks cocoa solids and sugar crystals into tiny pieces, so the chocolate feels smooth in the mouth. The speed and temperature of conching strongly affect the quality of the final chocolate.

Cocoa butter can set in six different crystal forms, named I through VI, and only one of them, Form V, gives chocolate its shine and snap. Tempering is the step that aims for Form V: the chocolate is heated, cooled and reheated to exact temperatures so that most of the cocoa butter sets in that one form. One way to do this is called seeding. Chocolate chunks that have already been tempered are stirred into melted chocolate, where they cool it and carry Form V crystals that the rest of the chocolate copies. After the cocoa mix is made, it is poured into molds, cooled, cut and wrapped, and the cooling takes at least 20 minutes to an hour.

Olmec people in what is now southern Mexico began growing cacao around 1500 B.C.E., and they likely used it for a ceremonial drink. In Europe, chocolate began as a bitter drink from the Americas, and Europeans made their own versions with cane sugar, cinnamon and other spices. Chocolate houses opened in big cities like London and Amsterdam. Chocolate reached Europe through Spain, though accounts disagree about exactly when. Hard chocolate bars did not appear until 1847, and chocolate in the 1800s was still hard to chew, so early hard chocolate was less popular than the improved kinds sold today.

Controlling sugar crystals is the main skill in candy making. Cooks stir at certain moments and keep syrup at certain temperatures to make candy grow crystals, as fudge does, or stay glass-like, as hard candy does. Corn syrup and honey interfere with sugar crystals, which keeps hard candy and caramel smooth instead of grainy. Fudge is a crystalline candy: the cook brings sugar syrup to the soft ball stage, then cools and stirs it at the right time so that many tiny crystals form, which gives a smooth texture. The hottest syrup, at the hard crack stage, makes crunchy candies like brittle and lollipops. Hard candy is a glass because its sugar is not arranged in crystals, and it is cooked very hot and then cooled quickly into a hard, brittle solid. The syrup begins to set right away, so candy makers must work fast.

The chew of a gummy comes from gelatin, a protein from animals that turns a sugary liquid into a soft gel, and the amount of gelatin sets how chewy a gummy is and how long it takes to dissolve in the mouth. Sorbitol, a sweetener used in some gummies, helps the candy keep its moisture so that it stays soft longer. Mixing the ingredients for a batch of gummies takes one to three hours, and then the batch goes to a quality control lab before it is formed.

Gummy candy is shaped in trays of starch. The candy mix is poured into dents pressed in the starch, and the starch keeps it from sticking. Making gummies the old way takes a lot of time and space: the starch trays need about 24 hours to dry, sometimes 48, so factories need large rooms with controlled temperature and humidity. Afterward, leftover starch is cleaned, dried with hot moving air and sent back to the machine, which is called a mogul.

A jelly bean has a soft middle and a hard shell made of sugar, and jelly beans are made from sugar, corn syrup and food starch. The middle and the shell usually match in flavor and color. Candy gets its bright colors from dyes that are added to it, because sugar is naturally white. The middles are shaped in trays of cornstarch, because cornstarch keeps the shape pressed into it, and a machine called a depositor squirts hot candy syrup into each tiny dent. A jelly bean is finished in a spinning pan, where sugar builds up on the soft middle and makes the hard shell, and then a glaze makes it shiny. Making one jelly bean takes 6 to 10 days from start to finish.

Most candy is made from sugar, and sugar comes from sugarcane or from sugar beets. In India, people learned to boil sugarcane juice into solid sugar, and around 250 C.E. sugar candy was made there, shaped like animals and people. Before that, the first candy in history was probably made with honey. A cave painting in Spain, about 8,000 years old, shows a person collecting honey from a beehive. Germs in the mouth use sugar to make acid, and the acid can eat tiny holes in the tooth's outer layer, so brushing teeth twice a day with fluoride toothpaste helps protect them from the damage that sugar can cause.

A 2020 study funded by the US Department of Labor and carried out by NORC at the University of Chicago estimated that about 1.56 million children were in cocoa-related child labor in Côte d'Ivoire and Ghana in 2018-19. About 95 percent of them were doing hazardous work. The study also found that in 2018-19 about half of children in cocoa-growing households were in cocoa-related child labor. The cocoa industry has promised to fix the problem. After that report, the World Cocoa Foundation, a group of cocoa and chocolate companies, said child labor remains a persistent challenge in those two countries.

Words to know

• refiners: fine-grinding machines
• tempering: heat and cool
• seeding: adding crystal starter
• conching: long stirring
• hazardous: dangerous