Deductive Wine Tasting: Building a Defensible Blind Conclusion
Deductive Wine Tasting is the domain where the exam tests whether you can identify a wine blind by building a defensible evidence chain, not by guessing. At Master Sommelier level, examiners expect a structured grid, precise descriptors, and a conclusion that follows from the observations.
The grid as evidence chain
Use the CMS deductive grid in order: appearance, nose, palate, conclusions. Record clarity, intensity, color and rim variation; then condition, intensity, aroma families and development; then sweetness, acidity, tannin, alcohol, body, mousse, flavor intensity, flavor characteristics, length and complexity. The conclusions must state quality, age, grape variety, country, region, appellation, vintage and style as appropriate.
Structural signatures
Read structure before flavor. Cool climates usually give higher acidity, lower alcohol and leaner body; warm climates give riper fruit, higher alcohol and fuller body. Tannin comes from grape skin, seed and stem contact plus oak. High acid with low alcohol suggests a cool site; high alcohol with low acid suggests a warm site or late pick. Use aroma only after structure narrows the field.
Worked example
A wine is pale ruby with medium+ acidity, medium+ tannin, medium alcohol, medium body, aromas of red cherry, rose, tar and dried herbs, and a long finish. Pale color plus high acid suggests a cool-climate red, but medium+ tannin rules out Pinot Noir. Red cherry, rose and tar are the classic Nebbiolo signature; medium alcohol and high acid fit Barolo better than warmer Langhe Rosso. Conclusion: Nebbiolo, Barolo, Piedmont, Italy, relatively cool vintage such as 2016, high quality. The reasoning is defensible because structure first eliminated competitors, then aroma confirmed the grape.
Traps
Do not name a grape before checking structure; do not confuse oak (vanilla, toast, cedar) with grape aroma; do not ignore vintage conditions (rain, heat, frost) that alter acid and ripeness; do not use vague descriptors such as 'nice' or 'earthy' without qualification; do not skip the quality statement; do not let a single aroma dominate the conclusion. Examiners penalize a correct guess with no reasoning as heavily as a wrong deduction.