Nutrition and applied sciences
Nutrition and applied sciences tests the physiology and chemistry behind what you taste and serve, plus the health and legal facts a sommelier must state accurately.
Alcohol and energy
- Ethanol provides about 7 kcal per gram - more than carbohydrate or protein (4 kcal/g), less than fat (9 kcal/g).
- A US standard drink contains 14 g of pure ethanol; a UK unit is 8 g.
- Grams of alcohol = volume (ml) × ABV × 0.789. A 750 ml bottle at 13% ABV: 750 × 0.13 = 97.5 ml, × 0.789 = 76.9 g, about 5.5 US standard drinks.
- Dry wine can still be calorie-dense through alcohol; sweetness adds sugar calories on top.
Sulphites and other compounds
Sulphur dioxide is added as an antioxidant and antimicrobial. In the US, wines with 10 ppm or more must state "contains sulfites"; the EU requires the same declaration and sets maximum total SO₂ levels. Sulphite sensitivity is real, but true allergy is uncommon; alcohol, histamine and dehydration are more often behind headaches. Red wine carries more histamine and tannin than white.
Metabolism and physiology
Alcohol is oxidized by alcohol dehydrogenase to acetaldehyde, then by aldehyde dehydrogenase to acetate. Genetic variants, notably ALDH2 in East Asian populations, cause flushing and raised risk. Aroma is perceived retronasally as well as orthonasally; astringency is a tactile sensation, not a taste.
Worked example
A 175 ml glass of 14% ABV wine: 175 × 0.14 = 24.5 ml ethanol × 0.789 = 19.3 g, or about 1.4 US standard drinks and roughly 135 kcal from alcohol alone.
Traps
Equating dryness with low calories. Confusing sulphite sensitivity with sulphite allergy. Blaming every headache on sulphites rather than alcohol, histamine or dehydration.