Sweetness perception: impression, not sugar
The standard
A perceived sweetness arises in the mouth, not in the laboratory: it depends on how sugar, alcohol, acidity and tannin balance one another.
Criteria
- Residual sugar provides the basic stimulus but does not determine the impression alone
- Alcohol and glycerol raise perceived sweetness, acidity and tannin lower it
- The impression concerns the overall effect, not a measured quantity
- Two wines with the same residual sugar can taste differently sweet
Distinction
Sweetness perception ≠ residual sugar: residual sugar is the measured quantity, the perceived sweetness its impression after balancing by acidity and alcohol. Sweetness perception ≠ fruit aroma: ripe fruit can feign sweetness without any sugar present.