Why popcorn pops
Each kernel of popping corn holds a tiny drop of water inside a hard, airtight skin. Heated to around 180°C, the water turns to steam, the pressure builds, and the skin bursts, turning the soft starch inside into a white foam that sets instantly. People have been popping corn for thousands of years: cobs of popcorn about 6,700 years old have been found in Peru.
POPCORN only reached cinemas in the 1930s. Owners of grand picture houses had thought it messy and cheap, but during the Great Depression it was one of the few treats people could afford, and street sellers were doing so well outside that cinemas began selling it themselves. In 1945 an American engineer called Percy Spencer noticed that a chocolate bar in his pocket had melted while he stood near a radar machine. One of the first things he tested next was a bag of corn kernels, which popped, and the microwave oven was on its way.
Crisps are older than the story
A popular story says that CRISPS were invented in 1853 at a hotel in Saratoga Springs, New York, by a chef called George Crum, who sliced potatoes paper-thin to annoy a customer who complained his fried potatoes were too thick. Nobody has found any evidence for it, and a recipe for potatoes fried in thin shavings had already appeared in an English cookbook in 1817.
In 1920 the Smith's company in London began selling crisps with a twist of salt in a little blue paper bag inside the packet, so customers could salt them themselves. The first flavoured crisps came much later. In 1954 Joe Murphy, who ran the Tayto company in Ireland, worked out how to add a flavouring during manufacture, and cheese and onion was born. Americans call crisps CHIPS.
Around the snack cupboard
The PRETZEL comes from southern Germany, and its loops are often said to have been shaped by monks to look like arms folded in prayer, though that story is hard to prove. It has been the sign of German bakers for centuries. CRACKERS began life as ship's biscuits, hard, dry and able to last for months at sea.
Peanuts are not really NUTS at all but legumes, like peas and beans, and they grow underground. Cashews grow on the outside of a fruit, inside a shell that contains an oil which burns the skin, so they are always sold shelled and cooked. OLIVES are too bitter to eat straight from the tree and have to be soaked in brine or water for weeks to make them edible.
HUMMUS is the Arabic word for chickpeas. Lebanon and Israel have competed to make the world's largest plate of it, and in 2010 cooks in Beirut made one weighing more than ten tonnes. JERKY takes its name from charqui, a word in Quechua, the language of the Incas, for dried meat, which kept for months in the cold, dry mountain air. Our Incas page covers the empire.
RAISINS are grapes dried in the sun until they lose most of their water. TRAIL MIX, a handful of nuts, raisins and chocolate carried on long walks, is known in America as gorp. A PITA puffs up in a hot oven as steam lifts the top from the bottom, leaving a pocket to fill with a DIP. The WAFER, BISCUIT, YOGURT and FRUIT in the grid round out the snack cupboard.