chemical and organoleptic effects of whole cluster fermentation
TRANSCRIPT
Chemical and organoleptic effects of whole cluster
fermentation
Whole Cluster Fermentation
Sabrine Rodems
M.S. Viticulture and Enology from UC Davis
Winemaker Wrath
Winemaker Scratch
Consultant
Whole Cluster—What does it mean??
Carbonic Maceration Component
Stem Extraction Component
Peer Reviewed Articles on Whole Cluster, Stem contents, Carbonic Maceration
Journal of Agriculture and Food Chemistry: Phenolic composition of grape stems . (Souquet, et al)
AJEV: The Effect of Various Carbonic Maceration Treatments on Must and Wine Composition of Marechal Foch. (Miller, et al)
AJEV: Transfer of Catechins and Proanthocyanidins from solid parts of the Grape Cluster into Wine. ( Sun, et al.)
Carbonic Maceration“These are not the Droids you are looking for”
--Obe Wan Kanobi
Carbonic Maceration
• You will get some carbonic characters but unless you are using a light grape like Gamay Rouge and are doing minimal intervention (anaerobic fermentation) you will not get the characters that we think of when we think of Beaujolais Nouveau—Rose petals, etc.
• The study by Miller and Howell from AJEV in 1989 concluded that the finished wine will have flavors such as “berries and cinnamon” but will be “softer due to lower extraction of phenols and reduced acidity” • I see the same reduced acidity in my
fermentations but it is not the result of CM. They assume in this study that the pH differences are due to “catabolism of malic acid in an anaerobic environment.”
We pump over twice a day rather vigorously, so this is not an anaerobic environment.
The conditions of the CM study were in sealed containers.
Chances are the chemistry, and phenolic and tannin composition are from the stems.
Both phenolic compound studies of the stems concluded that “wines made with stem contact contain higher concentrations of both total and polymeric phenols compared to those made without stems.”
Also, the Sun et al. study stated that the stems contributed the most amounts of flavan-3-ols that were retained in the wine. They contribute to astringency, bitterness, sourness, sweetness, salivary viscosity, aroma, and color formation. They are often found in tea and cocoa.
A lot of anecdotal evidence:
Sensory threshold for the flavor component is
about 25-30% whole cluster.
These flavors can be “stemmy”, rhubarb,
celery, spicy notes, bigger fruit characters from a
synergistic effect with the stem components.
More anecdotal evidence:
Perceived presence of the structural tannin
component is 10-20% whole cluster
The big question: why does the pH go up with higher whole cluster concentration??
It is clear to me this is not due to catabolism of malic acid due to my practices in the winery.
I have asked many winemakers and professors and I believe my hypothesis is probably true.
The acid is binding to the potassium in the stems and is either being pressed off with the must or causing the acid to precipitate.
Clone/WC treatment pH TA Alc.
Pommard 4--20% WC 3.66 0.59 14.47
Pommard 4--50% WC 3.73 0.59 13.91
Pommard 4-50+20% WC 3.88 0.57 14.71
P4/115 100% WC 3.86 0.63 13.8
Not Actual Data!!
More Actual Data: Acid Management W2014-09-10-044 - Wrath Wines
AF25579 - 14PN828100%-WR
Predictive Model Conditions
Condition Value
Starting pH 3.84
Starting TA (g/L) 4.64
pH post ML (no tartaric addition) 3.96
TA post ML (no tartaric addition) 3.32
Results Table
Tartaric Add Pre-ML pH Pre-ML TA Target pH Post-ML TA
g/L g/L (Post ML) g/L
3.69 3.42 7.61 3.50 6.29
3.23 3.46 7.21 3.55 5.89
2.80 3.50 6.84 3.59 5.52
2.30 3.55 6.42 3.65 5.10
1.93 3.59 6.12 3.70 4.80
1.49 3.64 5.76 3.75 4.44
Note: Post-ML TA does not account for weak acids generated during fermentation like acetic and succinic acids. Real post-ML TAs may be higher by greater than 1 g/L. These weak acids do not substantially affect pH. 1g/L Tartaric acid = 8.34 lbs/1000 gals.
Acid ManagementW2014-09-10-044 - Wrath Wines
AF25581 - 14PN828WB-WR
Predictive Model Conditions
Condition Value
Starting pH 3.92
Starting TA (g/L) 4.81
pH post ML (no tartaric addition) 4.08
TA post ML (no tartaric addition) 3.51
Results Table
Tartaric Add Pre-ML pH Pre-ML TA Target pH Post-ML TA
g/L g/L (Post ML) g/L
3.70 3.40 7.77 3.50 6.47
3.30 3.44 7.43 3.54 6.13
2.84 3.50 7.03 3.60 5.73
2.50 3.53 6.74 3.65 5.44
2.18 3.57 6.47 3.70 5.17
1.88 3.61 6.22 3.75 4.92
Note: Post-ML TA does not account for weak acids generated during fermentation like acetic and succinic acids. Real post-ML TAs may be higher by greater than 1 g/L. These weak acids do not substantially affect pH. 1g/L Tartaric acid = 8.34 lbs/1000 gals.
Actual Additions
LotWeighed tons Gallons Brix I
Brix Final Water add
Total Gallons Acid
14PN828WB-WR 1.22 195.2 26.8 24.5 18.32 213.52 2.5
14PN828100%WC-WR 1.02 163.2 27.1 24.5 17.31 180.51 2.8
Final Wine Data
Lot pH TA
667 20% WC 3.70 0.59
667 100% WC 3.83 0.61
Pommard 4 20% WC 3.76 0.65
Pommard 4 100%WC 3.89 0.68
P4 100%WC+828 100%+P4 Nat 3.86 0.60
828 20% WC 3.79 0.80
828 100% Whole Cluster 3.85 0.62
828 Whole Berry 3.67 0.71
What other winemakers think about whole cluster
Great article by PinotFilehttp://www.princeofpinot.com/article/865/
Lists Pro Whole Cluster interviews and No Whole Cluster interviews with many winemakers.
Pro’s seem to like the spiciness, structure, and complexity the stems give.
Anti seem be afraid of the green characters and they all seem to think the rachis needs to be brown.
We have to remember that we used to make wine always on the stem. It wasn’t French, it wasn’t German, it just was.
I like the characters I get from stems. The spicy notes, the rhubarb aroma, the tannin structure. I like the synergistic effect of the stem pushing the fruit forward.
The debate on weather or not we should be using “French” techniques on Californian wines is ridiculous in my opinion. We use a lot of French techniques. I see whole cluster as a tool to make my wines better. I want the structure, I want the complexity.
One thing we need to remember is that this is not France. The bigger fruit character concentrations we get in California really lend themselves to the added complexity that whole cluster imparts. It is the best of both worlds, old and new.
Now we just have to be careful and manage our pH’s.
Why do I use whole cluster??
