grape ripening – and how to manage it · grape ripening – and how to manage ... early...
TRANSCRIPT
Growing grapes for profitg g p p
What we want:What we want:• Balanced vines
• Ideal microclimate
• Open, productive canopy
• High yield and quality
• Low disease pressurep
• Vineyard access and mechanization
The management toolboxThe management toolbox• Site/variety/clone selection• Trellis design, training systemg , g y• Pruning strategy• Nutrient/floor management• Water management• Canopy management
The ‘how to’ for dummies
Principles:• Lower yield → better quality
p
WRONG!• More stress → better quality
WRONG!
It ain’t necessarily so…Qua
lity
12 95Yield
6
10
a)
90
ratin
g)
re)
5
6
8
eld
(T/h
a
80
85
Qua
lity
vint
age
r
eld
(t/ac
r
4
3
4
Yie
75
Qhe
by's
v
ualit
y
Yie
2
2 70 (Sot
h
Yield
Qu
r = 0.131
CA North Coast (Napa, Sonoma) Mean harvest Brix: 20.5 (1971) – 24.2 (2001)
1960 1970 1980 1990 20000 65
Change is in the air
20
25 Season and Cluster thinning1998 1999 (t/ha)
Early (13.7/5.2)Tons/acre6.1 - 2.3
15
20
(A52
0/mL) Late (13.7/6.1)
None (25.4/8.8)6.1 - 2.7
11.3 - 3.9
2876 2243 GDD (°F)
5
10
Col
or (
10 15 20 250
5
Soluble solids (Brix)
• Color varies >2-fold at the same Brix level• Too much (or too little) heat slows ripening• Temperature trumps crop load → nature trumps nurture
Xylem flow reversesBerry Growth
Cell expansionCell divisionCell division
Ripening: A trade deficit?
(modified fromCoombe 2001) SEED FORMATION BERRY RIPENING
What’s in a grape? Mostly water• Berry water content 70-80% at harvest• In: xylem and phloem• Out: transpiration and xylem backflow→ Berry very sensitive to temperature (+25ºF)• Veraison: phloem flow xylem flow reversedVeraison: phloem flow , xylem flow reversed→ Berry less sensitive to soil moisture
H2OXylem Phloem
Transpiration
Sugars: sweet seducers• Sweet taste and alcohol• > 90% of soluble solids (Brix)• Glucose + fructose (> 95% 1:1 ratio)• Glucose + fructose (> 95%, 1:1 ratio)• From sucrose via phloem• Sugar accumulation → veraison (~9 Brix)• Physiological maximum ~25 Brix→ Shrinkage increases concentration
( 10% weight → +2 Brix)(-10% weight → +2 Brix)
g) 350400450
Year 1 Year 2Year 3
gar p
er b
erry
(m
100150200250300
Year 3
Soluble solids (ºBrix)
Sug
5 10 15 20 25 300
50100
Acids: sour repellents• Sour taste, mask sweetness• Tartrate & malate (70-90%)• Also citrate succinate phenolics
Tartaric Malic• Also citrate, succinate, phenolics,
amino acids, fatty acids• From glucose before veraison• Ripening: tartrate → little turnover but dilution
malate → respiration & gluconeogenesis• High acidity → low pH (3-4 at harvest)g ac d y → o p (3 a a es )• Temperature!
1 ) 182022
Year 1Year 2 3.8
4.0 Year 1Year 2
able
aci
dity
(g L
-
81012141618 Year 2
Year 3
pH
3.2
3.4
3.6
Year 2 Year 3
Soluble solids (ºBrix)
Titra
ta
14 16 18 20 22 24 26 28246
Titratable acidity (g L -1)
2468101214161820222.8
3.0
Nitrogen: fuel for yeast
• Free amino acids (50-90%), proteins, NH4+, NO3
-
• Main amino acids: proline & arginine (>70%)Main amino acids: proline & arginine (>70%) • From NO3
- (via xylem) and glutamine (via xylem & phloem)• Ripening: mostly glutamine import,
proline & PR proteins accumulate (osmotic stress?)• Yeast uses arginine but not proline• PR proteins → protein haze (heat stability)• PR proteins → protein haze (heat stability)• Disease susceptibility
Phenolics: repulsion and attraction• Color, astringency (texture), flavor, oxidation• From amino acid phenylalanine• Stored as glycosides: bound to glucose
(and acetate/coumarate) or tartrate• Pre-veraison: tannins (skin and seeds) → astringency
+Glu
• Pre-veraison: tannins (skin and seeds) → astringency• Post-veraison: anthocyanins (skin) → color• Flavonols (skin: sunscreen) → copigmentation• Hydroxycinnamates (pulp), decline
post-veraison → volatile phenols• Sensitive to N light temperatureSensitive to N, light, temperature…
Volatiles: pick me!• Smell: aroma, flavor, odor, bouquet• 100s of compoundsp• Volatile profile is variety-specific → varietal aroma• Post-veraison: norisoprenoids (from carotenoids),
monoterpenes (bound to glucose)monoterpenes (bound to glucose)• Methoxypyrazines… (volatile)• Large fruit-to-fruit variation due to location, light, g , g ,
temperature, nutrition, harvest date, post-harvest handling
Harvest time: the challenge
Maximum fruit quality at optimum stage of maturityq y p g y
• Rule: The sooner grapes reach optimum, the better the wine
• Challenge: Determine optimum precisely, objectively, rapidlyChallenge: Determine optimum precisely, objectively, rapidly
• Final judgment: Taste end product (fruit, juice, wine)
• Problem: Too late too slow expensive subjectiveProblem: Too late, too slow, expensive, subjective…and: taste mostly limited to sweet-sour-astringent,
most flavors are ‘locked up’ in grapes
→ Solution: Measure sugar (Brix) throughout ripening…
Hang time: why do it?• Physiological maturity: Seeds able to germinate
• Grapes to specifications: Wine style, price segment…
• Ripening: Physical and chemical changes
• Water increases then decreases → concentration effect
• Natural sugar maximum at 23-25 Brix
• Tannins polymerize, bind to cell walls?p y ,
• Malate, methoxypyrazines decline early, not late
• Terpenes continue to accumulate late → aroma potentialTerpenes continue to accumulate late → aroma potential
• …but so do some volatile phenols → Brett fodder?
• Some ‘fruity’ ester precursors decline → fruit character?Some fruity ester precursors decline → fruit character?
• Danger: high pH → microbial stability?
Temperature: a West Side StoryDisentangling the light from the heat
Ph t th i +25°F!• Photosynthesis -• Sugar ( - ) (68-86°F)• Acids: Tartrate ( ?)
+25 F!
Acids: Tartrate ( ?)Malate
• K+pH (?)
• Amino acids (proline, arginine) • Phenolics: Anthocyanins - (days: 86-95°F)
Tannins ( ?)Tannins ( ?)• Volatiles (?): Methoxypyrazines • Sunscald: >108°F + UV/visible light
partly from Spayd et al. (AJEV, 2002), Tarara et al. (AJEV, 2008)
Light: visible and UnVisible
• Photosynthesis -• Sugar
-99% light!
• Acids: Tartrate ( )Malate
• K+ (?)pH (?)
K (?)• Amino acids (arginine ), N • Phenolics: Anthocyanins (color) (visible > 100 µmol m-2s-1)
Clouds vs. Canopy Shade
Flavonols (cofactors) (UV-B)Cinnamic acids (lignin, Brett…) (visible)Tannins (astringency) (visible?)Tannins (astringency) (visible?)
• Volatiles: Norisoprenoids, monoterpenes… Methoxypyrazines
• Wine sensory properties -
• White grapes cannot make anthocyaninsFair skins don’t tan…?
• White grapes cannot make anthocyanins,but they do make tannins
• Sun: too much of a good thing for white grapes?→ Flavonols → firmness, bitterness → Hydroxycinnamates → volatile phenols
(Smoke wood leather → pharmaceutical medicinal)(Smoke, wood, leather → pharmaceutical, medicinal)• Fruit character • Aromatic varieties sensitive, Chardonnay more forgivingy g g
(flavonoids → ‘structure’)• …but: less need for devigorating trellis, leaf removal, water deficit
Terroir is water:some stress is good more is better ?some stress is good, more is better…?
• Soil moisture determines vigor, canopy density, yield…• Sugar accumulation less sensitive than berry growthSugar accumulation less sensitive than berry growth• Some deficit is beneficial, but too much (too late) is detrimental
→ Berry size → Sugar -→ Seed ‘maturity’ ( ?)→ Acidity (malate )→ Acidity (malate )→ pH → Amino acids (arginine )→ Tannins ( ?)→ Flavonols… ( ?)→ Color (berry size + anthocyanin production)→ Color (berry size + anthocyanin production)→ Carotenoids ( ?)
Don’t let ‘em dry out!
(Lag phase)
Irrigation
(~20 Brix)
Irrigation
Days after irrigation from Keller et al. (JXB, 2006)
Plant water status and berry size
1.4Water less before veraison to limit berry size
1.0
1.2
ry w
eigh
t (g)
0.6
0.8Ber
r
Merlot (r = 0.53**) Syrah (r = 0.43*)Chardonnay (r = 0.51*)
30
40
50
%)
-1.4 -1.2 -1.0 -0.8
Pre-veraison Ψstem (MPa)
y ( )
10
20
30
wei
ght l
oss
(%
-20
-10
0B
erry
w
Merlot (r = -0.45*) Syrah (r = -0.41*)Chardonnay (ns)
-1.2 -1.0 -0.8 -0.6
Post-veraison Ψstem (MPa)
-30 Chardonnay (ns)
Water more after veraison to prevent weight loss
How to blow up 10
12
20
30
Chamber pressure Bunch NodeBerry - topTrunkBerry - middle
Pre-veraison
grape berries
mbe
r pre
ssur
e (b
ar)
4
6
8
mV
cha
nge
-10
0
10Berry middleBerry - bottom
Top
cham
-2
0
2
-40
-30
-20Middle
Bottom
0
10 3
5
6
minutes
0 100 200 300 400 500 600 700-2-40
Post-veraison
berry
siz
e (m
V)
-20
-10
0
KPa
2
Bar
2
3
4
Bunch 2
chan
ge in
-40
-30 1
0
1
2
Cracked berry
Bunch 2
time (minutes)
0 100 200 300 400 500-50 0 -1
Non-girdledGirdledVPDair
Chamber pressure
Cracking: low carbs but overweightWater through skin → Berry volume
S 150
200
g)
Concord Merlot
25 Concord, r = -0.80***
→ Sugar
100
150
sug
ar (m
g
20
25
(Brix
)
Merlot, r = -0.88***
50
Leac
hed
10
15
ry s
ugar
no yesCracking
0
5
10
Ber
r
• High humidityR i f ll
Cracking
0 100 200 300
Leached sugar (mg)
0• Rainfall• Sprinkler irrigation
Nitrogen: friend or foe?• Photosynthesis → growth • Sugar ( - )
T t t (?)• Tartrate (?)• Malate • K+ → pH p• Amino acids (arginine) • Anthocyanins, flavonols… • Carotenoids → terpenes • Other volatiles ( - )
350A i i NL) m
g/L)
150
200 ST/no NRT/no NST/90 kg N/haRT/90 k N/h
150
200
250
300
ug/m
L
A rginine-NP ro line-N
min
o ac
ids (
mg/
L
thoc
yani
ns (m
50
100
150 RT/90 kg N/ha
0
50
100
N 4 0+0 N 20+ 20S TD
N 0+ 40 N 40+0 N 20+ 20P RD
N 0 + 40 N 40+ 0 N 20+ 20RD I
N 0 +40
Juic
e am
Tota
l an
0
50
Day 0Day 2
Day 4Day 6
After pressAfter MLF
After cold st.
How to get poor color
50
Increasing N at bloomN1 N5 N10
10
20
30
40
Decresk
in fw
)
100%
Decre
0
30
40
50
easing lighns (m
g/g
s
20%
easing lig
0
10
20
50 Delphinidin-3-glc
ht at veraho
cyan
in 20% ht at vera
10
20
30
40 Cyanidin-3-glc Petunidin-3-glc Peonidin-3-glc Malvidin-3-glc
aisonAnt
h
2%
aison
00 2 4 6 8 0 2 4 6 8 0 2 4 6 8
Weeks after veraisonWeeks after veraison
Better ways to waste money…
100
Botrytized Healthy
er c
lust
er
wei
ght (
g)
100
1.0
1.5
8 Soil N
Ber
ries
pe
Ber
ry w
50
0.56
8
seve
rity
af)
0 g/vine 3 g/vine
Soil N (g/vine)0 0.2 1 2
0 0.04m
ildew
ssi
ons/
lea
(g )
2
Pow
dery
(le
Chardonnay Cabernet S.0
P
How much N to apply?24
100% Sunlight
°Brix
) 22N1N5N10
20% Sunlight
e so
lids (
20 mean = 20.4
20% SunlightN1N5N10
…it depends!
Solu
ble
18
N102% Sunlight
N1N5
1650 150 250 350 450 550
mean = 298
N10
Yield (g/vine)50 150 250 350 450 550
Avoid competition28 28
26
27
28
(°B
rix)
26
27
28
(°B
rix)
24
25
ble
solid
s
24
25
ble
solid
s
0 100 200 300 400 50022
23Sol
u
r = -0.44, p < 0.001
0 5 10 15 20 2522
23Sol
u
r = -0.47, p < 0.001
Berries/shoot Growing tips/shoot at veraison
• Too much crop may delay ripeningToo much crop may delay ripening
• Growing shoot tips compete with ripening berries
→ Limit (lateral) shoot growth after veraison→ Limit (lateral) shoot growth after veraison
Wh ?Fruit thinning
Why?• Regulates crop load (fine-tuning)
→ Prevents overcropping→ Prevents overcropping• May improve fruit composition• Can increase fruit size• May promote shoot growth
Wh ?When?• Early → shoot growth • Late → greater effect on yield• Late → greater effect on yield• Bloom: cut through flower clusters
→ cluster compactness • Veraison → quality control?• Pre-harvest → ??? (BS/BSN)
The ideal vine
• Shoots/canopy length 5/ft• Shoot length 3-4 ft (~15 buds)• Lateral shoots 5-8 buds/shoot• Pruning weight 0.2-0.5 lbs/ft• Cane weight 20-40 g• Leaf area/fruit weight* 10-15 cm2/gLeaf area/fruit weight 10 15 cm /g• Yield/pruning weight* 5-10• Canopy gaps ~ 30%• Fruit exposure > 50%Fruit exposure 50%
*Measures of crop load