Deductive Method

The Deductive Method — The Grid

skill-metadata

• skill-id: sommelier/tasting-evaluation/deductive-method
• skill-type: knowledge
• parent: sommelier/tasting-evaluation
• version: 1.0.0
• references: deductive-method/references/deductive-grid-schema.md

description

Encodes the CMS Deductive Tasting Grid as structured reasoning knowledge. Covers the full four-phase sequence — Sight, Nose, Palate, Conclusion — and teaches students to build a logical evidence chain from visual observation through to grape, region, and vintage identification. Essential foundation for blind tasting, exam preparation, and structured wine description.

When This Applies

Use this skill when the user is:

• Working through a blind tasting and needs to know what to observe and in what order
• Describing a wine in structured, exam-ready language
• Trying to identify a wine from its observable characteristics
• Preparing for CMS (Court of Master Sommeliers), WSET, or BNIC exams
• Learning to write a professional tasting note
• Conducting pairing research that requires understanding a wine's structural profile

The Grid Structure

The deductive grid is not a checklist. It is a detective's case file built in real time.

Each phase produces evidence. Each piece of evidence narrows the field of possibilities. By the time you reach the Conclusion, you have assembled enough facts to make an informed deductive leap — not a guess, but a reasoned argument.

The sequence is non-negotiable:

1. Sight — Establishes what the wine looks like before any expectation is formed by smell or taste. Color, clarity, and development are assessed cold.
2. Nose — First sensory engagement. Condition is assessed first (clean or flawed?). If flawed, the investigation pivots to fault diagnosis before continuing. If clean, intensity, development, and aroma categories are mapped.
3. Palate — The structural measurement. Sweetness, acid, tannin, alcohol, body, texture, and finish are assessed in sequence. These are the data points that will drive the conclusion.
4. Conclusion — The deductive leap. Using all evidence from Sight, Nose, and Palate together, reason toward: grape variety (or blend), region/appellation, vintage range, and quality level.

Think of it this way: Sight is the crime scene. Nose is the witness statement. Palate is the forensic evidence. Conclusion is the closing argument.

SIGHT

Clarity

• Clear — No suspended particles; normal and expected in most commercial wines
• Hazy — Could indicate unfiltered/unfined wine (common in natural wines, some Champagnes sur lie), a fault (protein instability, refermentation), or simply serving temperature effects. Note without alarm; context matters.

Brightness

• Dull — May indicate age, filtration issues, or low acidity
• Bright — Normal healthy wine
• Day-Bright — Vivid, luminous; often signals freshness and good acid
• Brilliant — Exceptional clarity and luminosity; often young, high-acid wines or precisely made still wines

Color — White Wines

Work from youngest to oldest. Color deepens with age, botrytis, oxidation, and warmer climates.

Color — Red Wines

Red wines lose color and shift from blue/purple hues toward garnet and then brick/tawny as they age.

Rim Variation

The color at the rim (thin edge of the tilted glass) vs the core (center of the wine) is one of the most reliable age indicators.

• No variation (rim = core) — Young wine; anthocyanins still fully intact
• Color difference (rim paler/more orange than core) — Age; anthocyanins are polymerizing and precipitating. An orange or brick rim on a red wine is a strong indicator of maturity (5+ years, or earlier in a warm vintage or lighter variety like Pinot Noir)
• Wide variation — Significant age; the wine is in or past its window

Viscosity / Legs / Tears

The streaks of wine that run down the inside of the glass after swirling are caused by the Marangoni effect — surface tension differential between water and alcohol.

• Thick, slow legs → Higher alcohol and/or residual sugar
• Thin, fast legs → Lower alcohol
• What they do NOT indicate: Quality. Legs/tears are not a quality marker. Never use them to compliment or criticize a wine. This is one of the most common misconceptions in wine service.

Gas Bubbles

• Persistent fine bubbles rising from a point — Traditional method sparkling wine (tirage creates nucleation points)
• Few large bubbles at rim — Charmat/tank method or slight carbonation
• Bubbles in a still wine — Possible slight refermentation in bottle; may be a flaw, or intentional in some styles (Vinho Verde, Txakoli, Muscadet pétillant naturel)

Sediment

• Fine powdery deposit — Tartrate crystals (not a fault; temperature-induced precipitation); or fine lees in unfiltered wine
• Chunky dark sediment — Tannin-pigment polymers from age in red wine; expected in aged Cabernet, Vintage Port, old Rhône
• Cork bits — Service issue, not a wine fault

Staining

• Deep staining on the glass above the wine line — High extract, likely a full-bodied, concentrated red; also older wines where tannin polymerization has created sediment

NOSE

Step 1 — Condition: Clean vs Flawed

Before anything else: is the wine clean?

• Clean — Proceed with intensity, development, and aroma assessment
• Flawed — Stop. Identify which fault descriptor applies. Route to fault-diagnosis skill for systematic identification and "send it back?" protocol. Common triggers: wet cardboard (TCA/cork taint), vinegar (VA), nail polish (ethyl acetate), rotten eggs (reduction/H2S), musty basement (TCA), bandaid (brett). Do not continue the grid until condition is assessed.

Intensity

How powerfully do the aromas present themselves without swirling, and after?

• Delicate — Restrained; aromas require concentration to detect; common in cool-climate aromatic whites (Mosel Riesling), aged wines where aromatics have faded
• Moderate — Clearly present but not dominating; most mid-range wines
• Powerful — Aromas leap from the glass; concentrated; common in warm-climate varieties, late harvest, some Burgundy Grand Cru

Intensity is diagnostic: high intensity + low alcohol is a marker of cool-climate concentration (sugar ripeness separate from flavor ripeness). High intensity + high alcohol is a warm-climate marker.

Development / Age

• Youthful — Primary fruit dominant; fresh, vibrant, uncomplex
• Vinous — The wine is "winey" rather than specifically fruity; some development beginning
• Developing — Secondary and early tertiary aromas emerging alongside primary fruit; the transition stage
• Complex — Multiple aroma layers; primary + secondary + tertiary all present; the wine has fully evolved
• Tired/Over the Hill — Aromas have faded, oxidized, or lost definition; the window has closed

Fruit Condition

Fruit condition tells you about climate, harvest timing, and hang time.

Fruit Types — Diagnostic Value

Citrus: Lemon, lime, grapefruit, yuzu, lemon curd

• Diagnostic: High-acid whites; cool climates; Riesling (lime, lemon), Sauvignon Blanc (grapefruit, lime), Chardonnay (lemon, grapefruit at cool end), Champagne base wines, Txakoli

Stone Fruit: Peach, apricot, nectarine, plum, cherry, cherry pit

• Diagnostic: White stone fruit (peach, apricot) = Viognier, warmer Riesling, white Burgundy, Gewürztraminer; Red stone fruit (plum, cherry) = Pinot Noir, Sangiovese, Grenache, Barbera

Tropical Fruit: Mango, pineapple, passion fruit, guava, banana

• Diagnostic: Warm climate or new world whites; Marlborough Sauvignon Blanc (passion fruit), warm Chardonnay (pineapple), Viognier in warm sites; also Champagne (pineapple, banana in riper dosage styles)

Berry Fruit: Strawberry, raspberry, blackberry, blackcurrant (cassis), blueberry, cranberry

• Diagnostic: Strawberry/raspberry = Pinot Noir, cool Grenache, Gamay; Blackberry = Syrah, Zinfandel, Malbec; Cassis = Cabernet Sauvignon (signature aroma); Blueberry = Malbec, Primitivo; Cranberry = cool-climate Pinot Noir, Nebbiolo

Tree Fruit: Apple, pear, quince

• Diagnostic: Green apple = Chardonnay (especially unoaked), Pinot Gris, Chablis; Ripe apple = Alsace Pinot Gris, aged white Burgundy; Pear = Viognier, Austrian whites, Pinot Blanc

Dried Fruit: Fig, date, raisin, prune, dried apricot, dried cherry

• Diagnostic: Age or concentration; Amarone/Recioto (dried cherry/fig); aged Barolo (dried rose, cherry); Tawny Port (fig, date, raisin); Sauternes aged (dried apricot, marmalade)

Non-Fruit Aromas

Floral

• Rose (dried vs fresh) → Pinot Noir, Nebbiolo (dried rose, violet), Gewürztraminer (rose petal), Grenache
• Violet/Iris → Nebbiolo (key signature), Malbec, Cabernet Franc
• White flowers (jasmine, honeysuckle, orange blossom) → Viognier (signature), Riesling, Muscat, Torrontés
• Acacia → Young Riesling, Soave (Garganega), Grüner Veltliner

Herbal / Vegetal

• Green pepper/capsicum (pyrazines) → Cabernet Sauvignon (cool climate), Cabernet Franc (characteristic), Sauvignon Blanc
• Asparagus → Sauvignon Blanc (can indicate overripe/under-ripe pyrazines), Grüner Veltliner
• Olive tapenade → Cabernet Sauvignon, Syrah (Provençal garrigue)
• Herbes de Provence/garrigue → Southern Rhône, Provençe, Languedoc
• Mint/eucalyptus → Australian Cabernet (Coonawarra especially), some Chilean Cabernet
• Fresh herbs (thyme, rosemary, lavender) → Grenache, Southern Rhône

Spice

• White pepper → Grüner Veltliner (signature; rotundone), Northern Rhône Syrah (signature)
• Black pepper → Syrah/Shiraz broadly, Zinfandel
• Cinnamon, clove → Gewürztraminer (spice character), some Grenache, some oak
• Star anise/licorice → Cabernet Sauvignon, Malbec, some Grenache
• Note: grape-derived spice (rotundone = pepper in GV/Syrah) vs oak-derived spice (vanilla, clove, nutmeg from barrel)

Earth / Mineral

• Forest floor, leaf litter, undergrowth → Aged Pinot Noir (Burgundy), aged Cabernet
• Wet stone, flinty, gunflint → Chablis (Kimmeridgian limestone), Loire Muscadet, Sancerre
• Chalk, limestone → White Burgundy, Champagne, Sancerre
• Volcanic ash, smoke, graphite → Etna wines, Austrian Grüner Veltliner (volcanic sites), some Ribera del Duero
• Iron, blood → Old-vine Pinot Noir, some aged Barolo
• Petrichor (rain on dry earth) → Aged Riesling, some aged Grenache

Oak Markers

• Vanilla → American oak (lactones); very common in Rioja Crianza/Reserva, New World Chardonnay
• Cedar, pencil shavings → French oak; Bordeaux, Napa Cabernet, aged Rioja Gran Reserva
• Toast, charred wood, smoke → Heavily toasted barrels; some New World reds, Californian Chardonnay
• Coconut → American oak (specifically oaklactone); new American oak barrels
• Butterscotch, toffee → Oak + partial oxidation; can also indicate diacetyl (MLF marker)
• Resin, sawdust → New or cheap oak; a sign of poor oak integration

Biological

• Brettanomyces (bandaid, barnyard, horse stable) → Brettanomyces yeast contamination; see fault-diagnosis
• Reduction (struck match, rubber, gunflint at high intensity) → H2S; see fault-diagnosis; low level can be stylistic
• Lees/autolysis (brioche, cream, biscuit, bread dough) → Extended sur lie aging; Champagne, Muscadet, aged white Burgundy
• Butter/cream → Malolactic fermentation; typical in barrel-fermented Chardonnay

PALATE — Structure

The palate is where you measure, not just describe. Each structural element has a defined scale.

Sweetness (Residual Sugar)

Note: perceived sweetness is modulated by acidity. A wine with 20 g/L RS and very high acid can taste medium-dry; a wine with 8 g/L RS and low acid can taste medium-sweet.

Tannin (Red wines and some skin-contact whites)

Level scale:

Nature descriptors (always include these — level alone is insufficient):

• Fine-grained / silky — Small, polymerized tannins; well-made, possibly aged; Pinot Noir, fine Cabernet with age
• Chalky — Powdery texture coating the gums; typical of limestone-grown varieties (Sangiovese, Nebbiolo), some Loire Cabernet Franc
• Grippy — Textural, dry without being harsh; often a sign of quality in tannic varieties
• Drying — Pulls moisture from the gums and cheeks; can be from tannin level or tannin nature (green/unripe tannins)
• Green / stalky — Unripe tannins from under-ripe or stemmy fruit; bitter, herbaceous tannin character; a fault in excess
• Ripe — Tannins polymerized and softened; fruit in balance; indicates optimal harvest timing or bottle age
• Coarse / aggressive — Young, extracted tannins from over-extraction or poor fruit; barrel aging should integrate these

Acidity

Level scale:

How to assess acidity on the palate: After swallowing, track how much saliva returns under the tongue and along the sides of the mouth. More saliva = higher acid. This is the most reliable assessment method — do not confuse acid with tannin (tannin dries; acid salivates).

Alcohol

Alcohol is felt as heat on the finish and back of the throat. Distinguish alcohol heat from tannin grip and from acid sharpness — they are felt in different locations and sensations.

Body

Body is the overall weight and viscosity in the mouth — a combination of alcohol, residual sugar, glycerol, and extract.

Texture

Beyond body, texture describes how the wine feels as it moves:

• Creamy — MLF, lees contact, or richness from oak
• Silky — Fine tannins, good integration; aged wine
• Grippy — Structural tannin; youth or variety character
• Oily / waxy — Some Riesling (kerosene note), Condrieu, old white Burgundy
• Tingly — CO2 (slight spritz in some still wines)
• Astringent — Drying, puckering; high tannin or acid; not a compliment in excess

Complexity

Does the wine offer layers? Do the flavors evolve on the palate, transition mid-palate, and reveal something different on the finish? A complex wine tells a story across the tongue from attack to finish; a simple wine is one-dimensional.

Finish Length

The finish should also be assessed for quality: is it clean, bitter, tannic, acidic, or alcoholic? A long but harsh finish is not a virtue.

CONCLUSION — The Deductive Leap

The conclusion is where all evidence is synthesized. Work in this order:

Step 1 — Climate Determination

Cool Climate Markers

• High acidity (Med+ to High)
• Lower alcohol (< 13% in reds, < 12.5% in whites)
• Lighter body
• Tart to ripe fruit (not jammy)
• Herbal, mineral, and floral notes prominent
• Lighter color in reds; more water-white to straw in whites
• Examples: Burgundy, Mosel, Champagne, Loire, New Zealand Marlborough, Oregon

Warm Climate Markers

• Lower to medium acidity
• Higher alcohol (> 13.5% in reds, > 13% in whites)
• Fuller body
• Ripe to jammy fruit
• Less herbal; more fruit-forward with spice
• Deeper color in reds (purple-ruby); deeper gold in whites
• Examples: Southern Rhône, Napa, Barossa Valley, Priorat, Mendoza, McLaren Vale

Moderate/Maritime Climate: Balance of freshness and ripeness; Bordeaux, Willamette Valley, Margaret River

Step 2 — Old World vs New World Style

Step 3 — Grape Identification by Structural Signature

White Wines

Red Wines

Step 4 — Region Narrowing

Once the grape is identified, narrow by structural intensity and style markers:

• Nebbiolo → high acid + chalky tannin + garnet-tawny → Barolo (more power) or Barbaresco (more elegance) → estimate age from development stage
• Cabernet → cedar dominates, restrained → Bordeaux left bank; ripe cassis + mint → Napa; eucalyptus → Coonawarra
• Pinot Noir → earthy + foresty → Burgundy; red fruit + brighter → Oregon or New Zealand
• Chardonnay → steely + no oak + high acid → Chablis; toasty + full + butter → Meursault or New World oaked
• Riesling → petrol + high acid + slate → Mosel; lime + full → Clare Valley; orange peel + complex → Alsace

Step 5 — Vintage Assessment

• Color (red wines): Purple-ruby = young (< 3 years typically). Ruby-garnet = mid-age (3–8 years). Garnet-tawny = older (8–15+ years). Brown edge = very old or heat-damaged.
• Development stage: Youthful = young vintage; Developing = approaching or in window; Complex = peak; Tired = past window
• Tannin texture: Young = grippy/drying; Mature = silky/integrated; Old = soft/fading
• Cross-check: Color age estimate + nose development + tannin texture should all align. If they don't, reason through why.

Quick Reference

The full grid with decision trees, diagnostic implications, and common misreads is in: tasting-evaluation/deductive-method/references/deductive-grid-schema.md

Learn Block

After substantive responses using this skill:

Learn ─── Aroma Lexicon
Next: Noble's Wheel gives you the vocabulary to describe what you just detected on the nose — the grid tells you where to look; the lexicon gives you the words.