COMPOSITION OF WINEWEEK 2

Sensory Evaluation

1

use for quiz #1

Components of Wine

Water: 80 to 95%AlcoholAcidsPolyphenolsSugarsCarbon Dioxide/CO2

2

use for quiz #1

3use for quiz #1

Components of Wine: Acids

Tartaric Acid: -the strongest acid

-Specific to grapes, rarely found in nature

Malic Acid: most prevalent in unripe grapes

Degrades as the grape ripens Can be degraded by lactic bacteria and turned

to lactic acid through malo-lactic fermentation

Together account for 90% of grapes acidity

4

use for quiz #1

Components of Wine: Acids

Help in stabilizing colorReact with alcohol to form esters (aromas)Uplift aromas and flavorsEnhance wine’s ageing potential Help to prevent microbial spoilage Balances residual sugar

5

use for quiz #1

Measuring acid through pH

Strength of acid is measured in pH units in grapes p – power H – Hydrogen ion concentration The property that gives a solution it’s acidity

• The lower the pH the stronger the acid• pH usually ranges between 2.5 and 4. in wine• For every decrease of 1 unit in the pH scale –

strength of acidity increases 10 times• Potassium ions replace Hydrogen ions as the berry

ripens and acids decrease• Values of 3.5 or less are preferable in finished wine

6

use for quiz #1

pH

pH measures the quantity of acids present, and the strength of the acids

Wine pH depends on three main factors: the total amount of acid present, the ratio of malic acid to tartaric acid and the amount of potassium present

Wines that contain little acid and excess potassium show high pH values.

Wine with more tartaric acid, less malic acid, less potassium and more titratable acid has lower pH values.

7

use for quiz #1

Important effects of low pH in wine

Low pH has many important effects: Making sulphur dioxide more effective as an

antimicrobial agent Inhibiting bacterial growth Improving the taste of the finished wine Increases the acid – balancing the wine

pH of approximately 3.4 - 3.5 usually provides the most balanced flavor for red wines

pH for white wines is effective when it is slightly lower (3.0-3.3)

8

use for quiz #1

Organoleptic Characteristics of Acids

Visual: Gives brilliance, reflective quality

Olfactif:Usually not perceivable but malic acid reminds of green apple, and can show up as “minerality” Taste: Has acidic flavor, tart and mouth drying leading to

salivationTactile sensation:

Felt on side of the tongue, plus salivation, mouth watering sensationMalolactic fermentation:

Adds creamy, buttery notes, plus added body/texture

9

use for quiz #1

Recommended Acidity

Dry White Wine - 0.65 % - 0.75 %Sweet White Wine - 0.70 % - 1.0%Dry Red Wine - 0.60 % - 0.70 %Sweet Red Wine - 0.65 % - 0.90 %Fortified Wines - 0.50 % - 0.60 %

10

use for quiz #1

Components of Wine: Polyphenols/Phenolic

Compounds Extracted mainly from grape skins and stems Group of chemical compounds that affect wines color,

texture, astringency and bitterness

Phenolic compounds responsible for red wine color areAnthocyanins – found in pulp cells under the skins of black

grapesIn red wine (200 to 500 mg/l)

Tannins: Large Phenolic compounds determine body and astringency – act as antioxidants and preservatives – precursors to aromatic compounds when wines are aged1 to 3g/l in reds Can also be found in very small quantity in whites(20-30mg/l) if matured in oak barrels due to wood tannins

11

Organoleptic Characteristics of Polyphenols

Visual: responsible for the color of red and white wine

Varying levels and specific to each varietalAs wine ages, tannins polymerize and form

sediments for red wines resulting in a lighter color

Color will deepen for whites due to oxidation

Taste: responsible for the astringency of wine

12

use for quiz #1

Astringency vs. Bitterness

Tannins brings astringency and structure Characterized by three sensations:

Constriction of sides of cheeks and gumsDusty, roughing sensation on teeth and gumsDrying sensationCan taste bitter

Bitterness is a flavor – not a feeling like Astringency

13

use for quiz #1

Components of Wine: Alcohol

Mostly ethanol, some methyl alcohol in small quantity

7 to 15% by volume (fortified up to 20%)Issued from fermentationIn most cases will be lower if residual sugar

is present but may still be very high if issued from hot climate

14

use for quiz #1

Organoleptic Characteristics of Alcohol

Visual: contributes to tears andviscosity when combinedwith glycerolTaste: In high quantity,

contributesto sweetness Contributes to mouthfeel

andviscosity and “heat” when

inexcess

15use for quiz #1

Components of Wine: Sugar

Mostly glucose and fructoseFound in varying degrees in finished wine

(Brix x 0.57 = potential alcohol)Converted to alcohol by fermentationIf detectable, characterized as

Residual Sugar listed as grams per liter (g/l)

Specific to wine type:Dry wine: less than 4 g/l (EU standards)

Sweet wine: can be up to and beyond 50 g/l

16

use for quiz #1

BRIX

Degrees Brix (symbol °Bx) Brix – measurement of sugar in the grape Formula for potential alcohol

Brix x .57 = potential alcohol

Measurement of sugar in the grape will determine how much alcohol that wine will potentially make

It’s the winemaking decision about converting all of the sugar into alcohol.

Some wine with residual sugar remaining will have lower alcohol in them as a result of stopped fermentation

17

use for quiz #1

Organoleptic Characteristics of Sugar

Visual: increased viscosity, increased potential alcohol in finished wine (tears)

Olfactif: Contributes to “ripe or honeyed” aromas but not necessarily detectable

Taste: Has a sweet flavor, rich mouthfeel andincreased palate weight

Increased heaviness/fatness if unbalanced

18

use for quiz #1

Components of Wine: Carbon Dioxide

Two forms:Dissolved (carbonic acids), detectable at

600mg/lFree: slight fizz to large bubbles, over

1000mg/l

19

use for quiz #1

Organoleptic Characteristics of CO2

Visual: bubbles

Olfactif: enhances and uplifts the aromas

Taste: has an acidic/tart flavor

Tactile Sensation: prickle on the tongue and a roughing of the mucus membrane

20

use for quiz #1

Balance-alliance of flavors

Sugar diminishes acid perceptionBitter (from tannin) will reinforce acid

tasteHigh acidity tones-down high alcoholHigh tannins must be balanced by

moderate acidityHigh alcohol volatizes esters and can

distort structure Low alcohol (RS) needs fresh acidity

and/or bright tannins

21

use for quiz #1

Balance of wine

In addition to fruit components, wine balance relies on:

Dry white: 2 structural elements: acidity and alcohol

Sweet white: 3 elements: residual sugar, acidity, alcohol

Red wine:Acidity, Alcohol (sweetness), Tannin

All elements must compliment each other and frame the fruit aromas and flavors

22

use for quiz #1