Extreme heat does more to our food than make it harder to source and more expensive; it can also alter its taste and composition. After a summer of severe heatwaves in 2026, France has had to rewrite its rules surrounding its wine and cheese production. The hot, dry weather pushed France’s grapes to ripen unusually quickly, increasing Champagne’s alcohol strength from 13% to 15% in bottles aged this year. In 2026, France’s cattle were forced to eat far more dried foliage than regular grass, changing the composition of many of the country’s famous cheeses. Extreme heat also affects lettuce, putting the plant under stress and causing it to grow prematurely, which gives it a bitter taste. Studies have found that heat-stressed hens tend to eat less, causing them to lay fewer eggs, which are significantly lighter and have weaker shells. According to a major 2025 study, heatwaves may cause such changes in the chemistry of the soil that it increases how much arsenic ends up in rice, making it dangerous to eat. Rising temperatures can also affect our seafood, making oysters riskier to eat, as bacteria flourish particularly well when the water is warm.