3,000-year-old honey found in Egyptian tombs is still edible. This is because honey contains about 80% sugars with close to no free water. It contains hydrogen peroxide released slowly by the glucose oxidase enzyme. It is also acidic, with a pH between 3.

3,000-year-old honey found in Egyptian tombs is still edible. This is because honey contains about 80% sugars with close to no free water. It contains hydrogen peroxide released slowly by the glucose oxidase enzyme. It is also acidic, with a pH between 3.2 and 4.5 which is close to vinegar. This combination of factors makes honey hostile to microbial life.