WinemakingWinemaking

AjarnAjarn

Dr. Charoen Charoenchai(PhD Food Sci & Tech, UNSW)Faculty of Home Economics TechnologyRajamangala Uni of Technology ThanyaburiPh 02 549 3175

c_charoen@yahoo.comwww.surathai.net

What is wine?What is wine?• Alcoholic beverage• Made by fermentation of grape juice

with• Yeasts• (+Malolactic bacteria)

Alcoholic beveragesAlcoholic beverages• Intended for leisure, pleasure• Not necessities (unlike other foods)• Sensorial qualities are most

important• They are crafted by masters of the

arts• The processes have specific names

MastersMasters• Viticulturalists (grow grapes)• Winemakers, Oenologists• Cellar masters• Brew masters• Master Distillers

Processes, ArtsProcesses, Arts• Viticulture• Oenology, Enology• Brewing• Distilling

(We don’t see master canner, milk maker, etc.)

Types of WinesTypes of Wines• By colour

– Red wine– Wine wine– Rose wine

Types of WinesTypes of Wines• By sweetness

– dry wine (< 7.5 g/l)– semi-dry wine– sweet wine (> 10 g/l)

• (Grape juice ~ 200 g/l)

Types of WinesTypes of Wines• By alcohol contents

– table wines 9 – 14 %– fortified wines 14 – 24 %

• eg. Sherry, port

Types of WinesTypes of Wines• By carbon dioxide contents

– still wine– sparkling wine

• Champagne• Sekt

Types of WinesTypes of Wines• By grape variety >100 varieties

– Cabernet Sauvignon– Shiraz– Chardonnay

Vitis viniferaVitis vinifera

• 9 varieties make excellent wines• Cabernet Sauvignon, Pinot Noir, Merlot,

Syrah (Shiraz), Riesling, Chardonnay, Semillon, Sauvignon Blanc, Chenin Blanc

• 28 varieties make good wines• Cabernet Franc, Gamay, Grenache,

Tempranillo, Zinfandel, Muscat, Muller Thurgau

• etc

Winemaking Winemaking ProcessProcess

Winemaking ProcessWinemaking Process• Grape picking• Destemming• Crushing• Pressing• Settling• Fermentation• Racking

• Fining• Maturation• Stabilization• Blending• Filtration• Bottling• Aging

PickingPicking

DestemmingDestemming

CrushingCrushing

Wine PressWine Press

FermentationFermentation

Grape Juice CompositionGrape Juice Composition• Sugar : glucose: fructose = 1:1

total ~ 20 %• Acids : tartaric, malic, citric• Vitamins, minerals• Nitrogen : amino acids• pH 3.2 - 3.5

Wine YeastsWine Yeasts• Saccharomyces cerevisiae• Many strains & brands• Active dried yeasts

Wine yeastWine yeast

C6H12O

6

2C2

H5

OH + 2CO

2Glucose Ethanol +Carbon dioxide

Alcoholic fermentationAlcoholic fermentation

96. by 0 . 7893 =

12%

2

0%

9. 6

%

Alcoholic fermentationAlcoholic fermentation

0 20 40 60 80 100 1200

50

100

150

200

250

0

2.5

5

7.5

10

12.5

Time (hr)

Gro

wth

(cel

ls x

10e

6/m

l); S

ugar

(g/l

)

Etha

nol (

g/10

0 m

l)

RackingRacking• Separate wine from lees• Sulfur dioxide addition

– Control oxidation– Control microbial

spoilage/refermentation

ClarificationClarification• Sedimentation• Fining• Filtration• Centrifugation

FiningFining• Protein, polysaccharides, tannin• Fining agents

– Bentonite– Gelatin– Egg white– Etc.

StabilizationStabilization• Cold stabilization

– potassium bitartrate, calcium tartrate

BlendingBlending• From different varieties• Different growing region• Different tanks• Wooded + unwooded• Etc.

MaturationMaturation• Chemical reactions

– Develop flavor compounds

• Tank maturation• Oak maturation

– Some oxidation– Wood extraction– Malolactic fermentation

Malolactic fermentationMalolactic fermentation

• (MLF)– Malic acid Lactic acid– Reduce acidity (increase pH)– Buttery flavor– Microbial stability (consume

sugar)• Lactobacillus, Oenococcus,

Pediococcus

MLFMLF• Occur naturally in some wines• Or inoculate bacterial culture• Beneficial in high acid wine

Wine undergoing MLFWine undergoing MLF

Cellar AgingCellar Aging• After bottling• Flavour

development

World’s WinesWorld’s Wines

French WinesFrench Wines• Quality System

– Vin de table– Vin de pays– Appellation Origine Controlle (AOC)

Red BordeauxRed Bordeaux• Cabernet Sauvignon, Cabernet Franc

and Merlot

Italian WinesItalian Wines

Australian WinesAustralian Wines• Barossa Valley, SA• Hunter Valley, NSW• No Quality system• Identify wines by grape variety eg.

Cabernet Sauvignon, Shiraz, Chardonnay

South Africa