Only One Kind of Corn Actually Pops
Popcorn is maize that bursts when heated. It works because of a hard hull and a precise amount of water trapped inside each kernel.
Popcorn is a variety of maize whose kernels explode when heated. Not all corn does this. The kernel needs a hard hull and about fourteen per cent moisture; heat turns that water to steam until the pressure bursts the hull and the starch inside turns inside out. Sweetcorn and field corn simply scorch.
- Corn that bursts when heated. *A bag of popcorn.*
- The snack made from it. *Popcorn at the cinema.*
- Popcorn as a modifier. *Popcorn ceiling.*
Word forms
| Form | Word | Example |
|---|---|---|
| Noun | popcorn | Salted popcorn. |
| Verb | pop | The kernels pop. |
| Related | kernel | An unpopped kernel. |
| Related | maize | A field of maize. |
| Related | hull | The tough hull. |
How it is used in a sentence
- Popcorn is cheap to make and expensive to buy.Which is why cinemas sell it.
- Store kernels in an airtight jar.Drying out stops them popping.
- Only a few kernels failed to pop.Usually because they had lost moisture.
Why it pops
- Hard hull — holds pressure until it fails suddenly
- About 14% water — too little and it will not pop
- Around 180°C — the temperature at which the hull gives way
- Starch — gelatinises and expands as the steam escapes
- Old maids — the industry term for kernels that never pop
An American compound of *pop* and *corn*, recorded from the 1820s. *Corn* means maize in America and any grain crop in older British usage.
Why do some kernels not pop?
Usually because they have dried out or their hull is damaged, so steam escapes before the pressure can build.
Does *corn* mean maize everywhere?
No. In Britain corn traditionally meant the leading local grain, usually wheat. Maize is the unambiguous word.