The first solid chocolate bar was invented in 1847 by Joseph Fry in Bristol, England.

In 1828, a Dutch chemist named Coenraad van Houten invented the cocoa press. This machine squeezed the fat, called cocoa butter, out of roasted cacao beans. It left behind a dry cake that people ground into cocoa powder for drinks.Joseph Fry found a new use for these ingredients in 1847. He mixed extra cocoa butter back into the powder and added sugar. This created a thick paste that stayed solid at room temperature. He called his invention 'delicious chocolate for eating.'The texture of a chocolate bar depends on how the cocoa butter crystals form. Cocoa butter is a special fat that can harden into six different shapes. Fry's method allowed the fat to cool into a stable structure. This gives chocolate its firm snap when you break it.This specific crystal structure also makes chocolate melt at about 93 degrees Fahrenheit. This temperature is just below the heat of a human body. Because of this, the solid bar stays firm in your hand but melts quickly on your tongue.Fry's company began mass-producing the 'Fry's Chocolate Cream' bar in 1866. This bar is still sold in stores today. It is the oldest chocolate bar brand in the world.