**Popcorn typically pops when the kernel reaches about 180°C (356°F). Yes, a 250°C oven is hot enough, and kernels can pop in a covered roasting pan.**

The temperature varies slightly between kernels. In a **2015 study**, researchers heated popcorn in an oven: 34% of the kernels popped at 170°C, and 96% popped at 180°C. Earlier measurements put the popping temperature around 177–187°C. [Popcorn: critical temperature, jump and sound](https://pmc.ncbi.nlm.nih.gov/articles/PMC4345489/)

Inside each kernel, heat raises the pressure of its trapped moisture. When the hull ruptures, the sudden pressure drop lets the hot water expand into vapour, puffing up the softened starch.

**The kernel temperature and oven setting are different things.** The oven needs time to heat the pan and the kernels; setting it above 180°C helps them reach popping temperature faster. Research comparing heating in oil and air confirms that heat transfer affects how quickly kernels pop. [Kinetics of Popping of Popcorn](https://www.cerealsgrains.org/publications/cc/2005/January/Pages/82_1_53.aspx)

For your roasting pan, I’d expect popping to work, but **a stovetop pan is easier to control for a good batch**. My practical concern with the oven is that early-popped pieces remain exposed to heat while the slower kernels finish. At 250°C, that gives you less margin before scorching.

If you want to experiment:

- Start with a small batch in a **fully preheated oven around 200°C**; treat this as a starting point.
- Use a roomy, oven-safe metal pan, with kernels in a single layer and plenty of space for expansion.
- Cover with an oven-safe lid that allows some steam to escape.
- Stay nearby and remove the pan promptly when popping slows substantially.

So: **about 180°C inside the kernel; 250°C will work, but I’d start lower for an oven trial.**