High Alcohol Wines: How to Manage Primary and Secondary

Fermentation

Presented by:Jessica Just of Scott Laboratories

andSigrid Gertsen-Briand of Lallemand

Winemaking Goals in a High Sugar Ferment

• Convert all sugar to alcohol

• Minimize the production of volatile acidity

• Minimize volatile sulfur off-aromas

• Balance % alcohol with phenolic maturity

• Complete the malo-lactic conversion in a timely manner

• Minimize microbial deviations

Glucose

Ethanol

Glycerol

Higher Alcohols

CO2

Biomass (≈ 2% glucose)

Organic Acids

Esters

H+

H+Internal pH is 5-6

External pH is 3-4

H+

H+

Yeast

Normal Fermentation Curve

2-4 million CFU/mL

>100-150 million CFU/mL

2-4 million CFU/mL

Time

Po

pu

lati

on

Survival factors are important to ensuring the proper working of the cellular membrane: poly-unsaturated

fatty acids and sterols

4-8 million CFU/mL

Higher yeast inoculation rate lowers dilution of the initial yeast

cells survival factors

Brix

Key Interrelationships of Factors Affecting Fermentation

SUGAR CONTENT

TEMPERATURE

CELLNUMBERS &

HEALTH

TOXICFACTORS

COMPETITIVEFACTORS

NUTRIENTS and OXYGEN

STRAIN SELECTION

MAXIMUMMAXIMUMFERMENTATIONFERMENTATIONMANAGEMENTMANAGEMENT

CapCap

Temperature Control in Red Must

• 20 Brix• 21 Brix• 22 Brix• 23 Brix• >24 Brix

• 95°F• 90°F• 85°F• 80°F• 76°F

Max. Temperature

What to Know Before Restarting a Stuck Alcoholic Fermentation

• Total residual sugar

• Glucose:Fructose ratio

• What caused the stuck fermentation

• Which yeast strain was used for the initial fermentation

• Temperature control

Dealing with a Stuck Alcoholic Fermentation

• Refer to websites for actual protocols• Blend• Sterile Filter• Long acclimatization, build-up with sugar• Short acclimatization with high inoculation rate• How many times should you try to restart a stuck

ferment? When can you start tasting the yeast?• Use of yeast hulls• Addition of nutrients?

0

1

2

3

4

5

6

7

8

9

10

11

12

Gra

do

alc

oh

ólic

o a

dq

uir

ido

(%

)

Productor 1 Productor 3 Productor 5 Productor 2 Productor 4 Productor 6

Alcohol content (% v/v) reached after fermentation in white wines with 56 selected Saccharomyces cerevisiae yeasts

that were able to ferment all sugars.

Alcohol content (% v/v) reached after red vinifications with 35 selected Saccharomyces cerevisiae yeasts that were

able to ferment all sugars.

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

B1 B2 B3 B4 C1 C2 D1 D2 D3 D4 D5 E1 E2 E3 E4 E5 E6 E7 E8 E9 E10 E11 E12 E13 E14 E15 E16 E17 E18 F1 F2 F3 G1 G2 G3

Gra

do

alc

oh

ólic

o a

dq

uir

ido

(%

)

Productor 1 Productor 3 Productor 5 Productor 2 Productor 4 Productor 6

WINEBACTERIA

Phenols(gallic acid & anthocyananins)

Growth & stimulation of MLF

Biogenic amine productionhistamine &

tyramine

Oak products

furfural

Mannoprotein

More efficient malic acid

degradation

L-lactate

L-Malate

0.1-0.2 units increase in pH

(palate)

Acetate

Diacetyl

Citrate

Pyruvate

Oxaloacetate Aspartate

Buttery, nuttyaroma/flavour

Fatty acids& Lipids

Pentoses

Lactate&

acetate

pentose phosphate pathway

Hexoses

Fructose

Pyruvate

D-lactate

Glucose

phosphoketoslase pathway

(Heterofermentative)

Embden-Meyerhof-Parnas pathway

(Homofermentative)

Trehalosedisaccharide

Monosaccharides

Polysaccharides

Sucrose, trehalosephenolic glucosides

Mouthfeelcontribution

(1->3) glucanse

Polyols

Glycerol&

erythritol

Glucose

Mannitol

Fructose

Mouthfeel & bodycontribution

SO2-acetaldehyde

Acetate & ethanol & free SO2

Bruised apple(green, vegetative)

Colour reduction

Adsorption by cells

Cell growth

Sugar-anthocyanin

glycosidase(anthocyanase)

Sugar + anthocyanidin

Glycoside (flavour)

Sugar + flavour-aglycon

-glucosidase

Increase in aromaCell growth

p-coumaric acid

4-ethyl guaiacol4-ethyl phenol

Phenolic acids

Spicy, clovesweaty, bandaid

Esterssynthesis & hydrolysis

Ethylestersesterase

ethyl lactate, ethyl acetate, ethyl

hexanoate, ethyl octanate

Fruity aromaHydrolase

?

Lipids

Volatile fatty acids

lipase

Protein

Peptides

protease

Bitterness ?flavour

Ethanol

Mousy compounds

Ethyl lactate

Ethyl carbamate

Off-flavour carcinogen

Citrulline, urea

Copper ions

Inhibitory to growth

Eveline Bartowski, AWRI, 2004

Key Interrelationships of Factors Affecting ML Fermentation

ALCOHOL CONTENT

TEMPERATURE

CELLNUMBERS &

HEALTH

TOXICFACTORS

COMPETITIVEFACTORS

NUTRITIONALFACTORS

STRAIN SELECTION

INTERACTION OF PARAMETERS

10x volume of water

bacteria

+ 10x volume of winepH > 3.5

20 MINUTES

After 18 – 24 h

Final wine

volume

Conclusion

• Proper inoculation rate

• Strain selection

• Proper Rehydration

• Temperature Control

• Balanced nutrient (and oxygen) additions

• Timing of additions

Thank you!

• For more information on any of these HUGE topics… please contact:– Jessica Just (jessicaj@scottlab.com)– Sigrid G-B (sigrid@lallemand.com)