Food is chemistry that you can eat. Five facts for your next dinner.
1. Why onions make you cry
Cutting an onion releases sulfur compounds that react with the water in your eyes to form a mild sulfuric acid. Your eyes produce tears to wash it out. Chilling the onion first slows the reaction.
2. Why koshary (and most stews) tastes better the next day
Starches from the pasta and rice absorb flavour overnight. Acids mellow. Fats distribute. The same dish at 4pm and 4pm-the-next-day are genuinely different.
3. Why the middle of a cake cooks last
Heat travels through cake slowly — about 1cm per 10 minutes at oven temperature. A 10cm cake needs its middle to endure an hour of heat flow.
4. Why rice needs to rest after cooking
Moisture inside each grain needs time to equalise. Lift the lid too early and the outer grains are soft while the inner ones are still firm.
5. Why freshly-baked bread stales faster in the fridge than on the counter
Cold temperatures accelerate retrogradation — the crystallisation of starch — which is what makes bread go stale, not dehydration. Fridge is the worst place for bread.