Transcript Gestion de la fermentation alcoolique

Alcoholic fermentation
management
The yeast’s life: from rehydratation to
the end of the sugars
Alcoholic Fermentation scenario
I
II
III
IV
V
Latency phase: enzymatic
and physiological adaptation
Growth phase: first third
of the alcoholic
fermentation. Good
physiological level, low
population level
Slowing down phase
Stable phase: the
population reached its
maximum level. Second
third of the alcoholic
fermentation. Good
population level, average
physiological state.
Decline phase: Damaged
level of population and
physiological state.
IV
V
II
THREATS
OBJECTIVES
SOLUTIONS
The yeast’s life during the alcoholic
fermentation
III
IV
V
II
I
I. Latency period
THREATS
OBJECTIVES
•Aggressiveness of
the must (pH, sugars,
SO2, toxins,
temperature)
•Good physiological
state with no
population loss
•Indigenus flora
competition
•Short latency period
III
SOLUTIONS
•Good practises for
the rehydration
•Choice of the yeast
•Yeast dose: at least
20 g/hL
IV
V
II
I
Latency
phase
Key points for the rehydration
-DO NOT USE MUST at the beginning of the rehydration.
- WATCH THE TEMPERATURE of the leaven and the must. Yeasts
are very sensitive to variations in temperature. It is essential to use
a thermometer for every step of the rehydration.
-ADAPT THE DOSE of yeasts to the must you want to ferment.
Increase the amount in case of Augmenter le dosage en cas de
vendange altérée, présence récurrente ou soupçonnée de
Brettanomyces, degré alcoolique potentiel > 13 % vol. Dose
minimale : 20 g/hL.
- IF NECESSARY, USE A YEASTS’ PROTECTOR (We will come
back to it later)
- INOCULATE AS SOON AS POSSIBLE
Inoculation step by step
Rehydration is a crucial step in the
life and efficiency of the yeasts
Safe inoculation
0
Mix the yeasts in 10 times their
water weight at 37°C (dose:
20g/hL)
No link between the present
foam and the yeasts
effectiveness
Wait for 15 minutes
Acclimate the leaven to the temperature by
adding must progressively
Objective: not more than 10° between the
leaven temperature and the must
temperature
Total rehydration time (step 1 and 2) must never
exceed 45 minutes
Incorporate the leaven to the must with
a homogeneisation remontage
Add ECOBIOL PDC
(water: 43°C; Volume:
20 times the yeast
weight) and then go to
step 1
How to choose the best yeast ?
• Technological criteria: Choose a strain
adapted to the alcoholic and tempeature
conditions.
• Qualitative criteria: wine style, aromatical
potential revelation, etc...
Manage the inoculation rate
Impact on the latency phase
Length of the latency phase
70
60
Time (hours)
50
10 g/hL rep1
10 g/hL rep2
25 g/hL rep1
25 g/hL rep2
40
30
20
10
0
14°C/ 15NTU
28°C/220 NTU
Echelle labo (15,4 % vol)
14°C/11 NTU
28°C/193 NTU
Echelle pilote (14,3 % vol)
Manage the inoculation rate
Impact on the end of the
alcoholic fermentation
10 g/hL rep1
10 g/hL rep2
25 g/hL rep1
25 g/hL rep2
Concentration (g/L)
Residual
sugarsen
atfin
thedeend
Sucres
résiduels
FAof the
alcoholic fermentation
20
18
16
14
12
10
8
6
4
2
0
14°C/ 15NTU
28°C/220 NTU
Echelle labo (15,4 % vol)
14°C/11 NTU
28°C/193 NTU
Echelle pilote (14,3 % vol)
II. GROWTH PHASE AND SLOWING
DOWN PHASE
THREATS
OBJECTIVES
•Must nutritional
deficiency
•Biomass too important
• Pushed clarification
(lack of sterols)
III
SOLUTIONS
• Get a reasonable
population whithout
degrading the
physiological state of
each individual.
•Complement at the
right time and only if
necessary
•Favoriser un bon niveau
de stérols dans la levure
•Management of the
oxygen and yeasts
protection
• Limit the provision of
amoniacal nitrogen
IV
V
II
I
Growth phase and
slowing down phase
Complement only if necessary (1/2)
Nitrogen
SO2
Henschke P.A. and V. Jiranek, Int.
Symp. on Nitrogen in Grapes and
wines,1991, 172-184
nitrogenous
group
S2méthionine
Impact of a nitrogen deficiency on the production of
components sulphured by the yeast.
Accumulation on
sulphured
components
(H2S…)
Complement only if necessary
(2/2)
The deficiency line
vary according to:
- sugars
- temperature
-Yeast strain
A z o t e a s s im ila b le ( m g /l)
Variability of the musts nitrogen composition
500
N a s s im ila b le
N a m m o n ia c a l
400
300
200
Seuil de carence moyen
100
0
0
25
50
75
M out
High maturity= strong [Sugar] and low [N]
100
Add nutrition at the RIGHT time
dCO2/dt (g/l.h)
1.5
1.0
Control
Add at the
beginning of
the AF
0.5
Add around
1040
0.0
0
100
200
T (h)
300
400
Sablayrolles, INRA
The best moment for nitrogen provision is at the end of the growth
phase, right after the yeast population reached its higher level.
For practical purposes, it is often necessary to add a little bit more in the
beginning of the alcoholic fermentation, in order to not bring too much
nitrogen at one third of the alcoholic fermentation (thermal peaks risks).
Limit the ammonia
nitrogen provision (1/5)
Assimilable nitrogen
sucres
The organic nitrogen (amino)
has a slower and more
regulated assimilation than
ammonia nitrogen
Amino nitrogen
Ammonium
time
Limit the ammonia nitrogen
provision (2/5)
Nitrogen: auto-consumption of the yeast’s amino acids and consequences
Ammonium
add
Fast consumption of ammonium
by the yeasts.
Fast yeast growth
Very important
yeast
Formation of H2S
Liberation of
radicals S2-
Fast impoverishment
of the environment
Consumption of its own amino
acids (even sulphured) by he
yeast
Inferred nitrogen
deficiency
Difficulties with the
FML
Limit the ammonia nitrogen
provision (3/5)
H2S liberation speed
(mmol/g poids sec/h)
15
10
Jiranek, 2000
5
heures
0
12
15
18
21
The add of DAP leads to more biomass, which is then deficient,
autoconsume its AA, liberates radicals S2- and produces even more H2S
Limit the ammonia nitrogen
provision (4/5)
Intensité
perception des
soufrées
Intensity
of thedeperception
of odeurs
sulphured
smells
Perceived olfactory
Intensité olfactive perçue
intensity
2,5
2
1,5
Témoin
DAP
1
Nutriment complexe
0,5
0
ICV, dept.
R&D
Chardonnay must (NFA : 140 mg/l) completed by
20 g/hl of « complexe nutriment » or 7.5 g/hl of DAP
Limit the ammonia nitrogen
provision (5/5)
Role on the wine positive aromas
The asimilation of the ammonia nitrogen by the
yeast is made to the detriment of the one of:
– The amino acids that are likely to intercede in the
production of fermentary aromas.
– The varietal thiols’ pioneers (grapefruit, passion fruits
aromas)
Conversion of the thiols pioneers: the
nutrition role
Subileau & Salmon, FEMS Yeast Res 8 (2008) 771-780
500
450
400
350
300
250
200
150
100
50
0
Sauvignon
blanc
Languedoc 2004
Témoin
Ajout de DAP
3MH
A-3MH
Sauvignon blanc
Gers 2006
7000
6000
Too much ammonium add at the
beginning of the FA can limit the
entrance of the pioneer into the the
yeastand then limit the thiols
production.
5000
4000
Témoin
3000
Ajout de DAP
2000
1000
0
3MH
A-3MH
Conversion of the thiols pioneers: the
nutrition role
buis, fruit de la
passion
A-3MH: > seuil
pamplemousse,
fruit de la passion
3MH*: > seuil
buis, genêt
Wines composition of volatile thiols
(sauvignon 2010, Sancerre)
4MMP*
DAP
Nutribio
0%
20%
40%
60%
80%
100%
120%
Indice de concentration indexé (Témoin = 100%)
Trials realized in partnership with the SICAVAC
140%
160%
Aromatic expressions:
the yeast nutrition effect
70.0
Wine positive aromatic composition
(Sauvignon 2010, Sancerre)
Organique
Complexe
Minéral
60.0
Somme des concentrations (mg/L)
50.0
40.0
30.0
20.0
10.0
0.0
Total esters x10 (acétate et esters éthyliques) Total autres arômes positifs (2-phényléthanol,
4-vinylguaiacol, beta-damascénone)
Trials realized in partnership with the SICAVAC
YEAST
PROTECTION
2 good reasons to protect your
yeasts
• Avoid stopping the alcoholic
fermentation
• Limit the stress of the yeasts and
the production of inhibitory toxins
What is the PROTECTION?
What is the difference between
protection and nutrition ?
NUTRITION
PROTECTION
Yeasts protection
How to manage the membrane
integrity of the yeast ?
 the central role of the sterols
The membrane: an interface
acidity
pump
Sterols
acidity
acidity
energy
acidity
energy
Sugars
transportation
proteins
Alcoholic Fermentation
[Acidity]
pH int. = 5-6
[Acidity] pH ext. = 3-4
Effect of a sterols deficiency
acidity
acidity
acidity acidity
acidity
acidity
acidity
acidity acidity
acidity acidity
acidity
energy
acidity
acidity
acidity acidity
acidity
acidity
Ethanol
pH Int.
Alcoholic
Fermentation
Importance of the time when
oxygen is added
1
.
5
0
1 : initial addition
1
.
2
5
2 : addition at the
end of the growth
phase
dCO 2/dt(g/l.h)
1
.
0
0
0
.
7
5
0
.
5
0
0
.
2
5
-Best moment=
end of the growth
1 2
0
.
0
0
05
0
1
0
0
1
5
0
2
0
0
2
5
0
3
0
0
3
5
0-Best moment
considering the
T
(
h
)
oxydation risk
1 : ajout initial
2 : ajout en fin de croissance
Yeasts protection
Dilution of sterols during growth phase
 at the end of this phase : low level 
potentialy weak yeasts
Protector
Oxygen
Yeasts protection
What is a yeast protector ?
Specific
Sterols
Rehydratation water
ProtectorNATSTEP®
(Inactivated
specific yeast)
Microprotectants
Micellar structure
Yeasts protection
Protector
Oxygen
Non protected yeasts
Yeasts protected by
Bioprotect®
Effect on the protection on
the viability of the yeast
Cellular viability (%)
100
90
80
70
95
100
105
110
115
120
Time (hours)
Control
Specific sterols added during
the REHYDRATATION
70%
90%
Viability
The effect of the protection on
the fermentation security
Straight end of the fermentation
Protecteur NATSTEP
Lenght of the alcoholic fermentation on different trials
Témoin
Sémillon 2006 (TAP 12,3 % vol.)
Grenache+Syrah 2007 (TAP 12,6 % vol. - Az. assim. 140 mg/L)
Cabernet franc 2007 (TAP 11,3 % vol. - Az. assim. 190 mg/L)
Sauvignon 2007 (60 NTU - TAP 11,5 % vol. - Az. assim. 210 mg/L)
0
5
10
15
Time after inoculation
(days))
Temps après levurage (jours)
20
25
IV. STABLE PHASE
THREATS
OBJECTIVES
•Increase of the
alcoholic level +
temperature
• Control of temperature
• Avoid diversions and
control them
• Organoleptical risks
III
SOLUTIONS
•Avoid ammonium salts
provisions that lead to
temperature peaks and in a
general way, avoid the
nitrogen provisions
•Limit oxygen provisions
IV
V
II
Stable phase
I
The yeast still can assimilate nutrients (nitrogen and oxygen also) at
this step but with much less efficiency.
V. DECLINE PHASE
THREATS
OBJECTIVES
• Maximum hostility of the
environment (alcohol,
temperature, toxins, floras
development)
•Risks of languish
alcoholic fermentation or
stops.
III
SOLUTIONS
•Limit the toxicity of the
environment
• Detoxification
• Control of the temperatures
• Optimise the
physiological state of the
surviving yeasts
• Everything hangs on the
beginning of the alcoholic
fermentation: nitrogen,
oxygen, sterols
Decline phase
IV
V
II
I
The yeast still can assimilate nutrients (nitrogen and oxygen also) at
this step but with less and less efficiency.
Conclusion
• Everything takes place during the first
phases :
– Choosing the yeast
– Rehydration (temperature, time, protection,
etc...)
– Inoculation (Inoculation rate, temperature,...)
– Growth phase and beginning of the stable
phase: nutrition, oxygen provision
Optimisation of the alcoholic
fermentation conditions (1/2)
Aggressiveness of the
environment
Alcohol >13,5 % vol
and/or Turbidity < 80 NTU
and/or T°<15°C or >28°C
Extreme nitrogen
deficiency
Assimil nitrogen <100
mg/L
BIOPROTECT rehydration
+
BIOCLEAN 2/3 FA
If 2 combined factors
•beginning FA: VITISTART (whites/rosés) or
ACTIVIT (reds) 20 g/hL
•1/3 FA: ACTIVIT 20 g/hL + DAP 15 g/hL
by alcohol degree below 12.5%
If the yeast needs a lot of nitrogen, calculate as if there was one
more alcohol degree. If it doesn’t need a lot of nitrogen, one
alcohol degree less.
Optimisation of the alcoholic
fermentation conditions (2/2)
Medium nitrogen
eficiancy
assimilable nitrogen
between 100 and 140 mg/L
•Beginning of the FA: NUTRIBIO 20 g/hL +
thiamine
•1/3 FA: VITISTART (whites/rosés) or
ACTIVIT (reds) 20 g/hL + DAP 15 g/hL by
alcohol degree below 12.5%
Light nitrogen deficiency
assimilable nitrogen
between 140 and 220 mg/L
•Beginning of FA: thiamine
•1/3 FA: NUTRIBIO 40 g/hL + DAP 15 g/hL
by alcohol degree below 13.5%
If the yeast needs a lot of nitrogen, calculate as if there was one
more alcohol degree. If it doesn’t need a lot of nitrogen, one
alcohol degree less.