Volume to weight for cooking ingredients.
Milliliters (volume) only equal grams (weight) for water (density 1.0 g/mL). Every other substance differs: oil is lighter (0.88-0.92 g/mL), honey is much heavier (1.42 g/mL), and milk is slightly heavier than water (1.03 g/mL). This means 250 mL of honey weighs 355g, while 250 mL of oil weighs only 220g — a 60% difference. For dry ingredients the discrepancy is even larger and less predictable (flour density depends on how settled it is). Always check the specific gravity of your ingredient for accurate conversions.