Hormonal Control of Grape Berry Ripening

The first steps of berry development, from fertilization to nouaison (fruit set) are under the control of developmental hormones such as auxins, cytokinins and gibberellins that promote cell division and cell expansion. These hormones reach a maximum concentration just before véraison and then decrease sharply upon ripening. Ultimately, the final size of the berry depends on how many seeds it contains.

The three hormones responsible for the grape berry maturation post-véraison include:

• Abscissic acid:
• shows a considerably accumulation after véraison
• a delay in ABA accumulation correlated with a delay in the import of hexoses and may play a role in sugar accumulation
• may also positively influence the accumulation of phenolics in the grape
• plays a role in seed maturation and seed dormancy
• resistance to water stress deficit
• specifically involved in seed maturation control
• Ethylene
• present at low but steady levels along berry development and ripening
• may have in regulating the vascular fluxes associated with berry ripening
• implicated in the reduction of berry acidity during the ripening phase
• exogenous ethylene treatment at véraison was shown to enhance the accumulation of anthocyanins in grape berries
• can have an effect on development of grape flavour and aroma
• Brassinosteroids
• concentration in the grape increases at the onset of ripening
• exogenous treatment of these hormones has hastened berry ripening

References:
1. Text and illustration from: Carlos Conde, Paulo Silva, Natacha Fontes, Alberto C. P. Dias, Rui M. Tavares, Maria J. Sousa, Alice Agasse, Serge Delrot, Hernâni Gerós, Biochemical changes throughout Grape Berry development and fruit and wine quality, Food, 1(1), 1-22 ©2007 Global Science Books.

Grape Berry Development and Ripening

Grape berries exhibit a double sigmoid growth pattern.

The First Growth Phase:

• occurs from flowering to approximately 60 days post flowering
• growth occurs mainly by cell division causing the berry to expand
• tartaric and malic acids are the most prevalently accumulated compounds during the first growth phase
• tartaric acid is accumulated during the initial phase it's concentration is highest in the periphery of the grape berry
• malic acid is accumulated in the flesh cells at the end of the first growth phase
• hydroxycinnamic acids accumulate in the flesh and skin of the berry
• tannins, including the monomeric catechins, accumulate in the skin and seed tissues but nearly absent in the flesh

Lag Phase:

• the length of the lag phase is specific to the variety
• the end of the lag phase corresponds to the end of the herbaceous phase of the fruit

Second Growth Phase or Ripening

• berries switch from a status where they are small, hard and acidic, with little sugar to a status where they are larger, softer, sweeter, less acidic, and strongly flavoured and coloured
• ripening phase begins in August in the north hemisphere and lasts about 45 days, depending on the environmental conditions
• the berry approximately doubles in size between véraison and harvest
• the solutes accumulated in the grape berry during the first period of development remain at harvest; but due to the increase in berry volume, their concentration is significantly reduced
• malic acid is metabolized and used as an energy source during the ripening phase
• tannins also decline considerably on a per-berry basis after véraison
• lthough the first growth period contributes to the final quality of the berry, the most important event occurring during the second growth period is a massive increase in compounds, the major ones being glucose and fructose, as a result of a total biochemical shift into fruit ripening mode

References:
1. Text and berry illustration from: Carlos Conde, Paulo Silva, Natacha Fontes, Alberto C. P. Dias, Rui M. Tavares, Maria J. Sousa, Alice Agasse, Serge Delrot, Hernâni Gerós, Biochemical changes throughout Grape Berry development and fruit and wine quality, Food, 1(1), 1-22 ©2007 Global Science Books.
2. Illustration of the double sigmoid curve from: Moschou, Panagiotis & Aziz, Aziz & Roubelakis-Angelakis, Kalliopi, Chapter 7, Polyamines and grape berry development, The Biochemistry of the Grape Berry, (2012), 137-159.

Biochemical changes throughout Grape Berry development and fruit and wine quality

Recently, I began reading this online freely available article called Biochemical changes throughout Grape Berry development and fruit and wine quality published in 2007. Although it is now a rather dated reference, it nevertheless contains some really good information that I am going to summarize, mainly for myself but hope that it is useful for you, too.

What is it about the grape that makes it an ideal fruit with which to make wine?

• a high concentration of sugars and other nutrients that provide a luxurious medium for the growth of wine yeasts
• a natural acidity, which is high enough to inhibit the growth of undesirable and noxious microorganisms during and after fermentation
• a high concentration of ethanol produced by sugar fermentation, which contributes to inhibit microbial activity in the product
• a unique presence of aromas and flavours

The grape contains all of these properties that can be transformed into a delicious liquid---wine. But, what does it take to make this liquid, the ultimate expression of the grape?
Viticulture

• wine quality largely depends on the vineyard and on the vine grower; the most important factor for viticulture is climate, and above all, temperature
• the French term “terroir” is used to refer to characteristics such as soil composition (minerals, soil density), sunlight, climate (temperature, precipitations), topography and “terroir” can also take into account strains of microorganisms usually found on the berry skin (the indigenous yeast and bacteria)
• the soil type depends on how the geological parent material has been altered and shaped by physical, chemical and bioglogical processes
• rainfall and drought also play an important part; it is almost impossible to grow wine with less than 200 mm (~8 inches) of rain a year
• moderate climate, with adequate to relatively high rainfall, provides ideal conditions for producing both fragrant white wines with good structure and acidity, and well-balanced red wines with good potential for maturing

The Grape

• most of the wine compounds are produced by the plant itself, in leaves (sugars and acids), and in berry (acids and phenolics)
• some molecules related to aroma and taste are produced during the fruit development and ripening; these aromas, called primary aromas are characteristic of the varietal

Reference:
1. Carlos Conde, Paulo Silva, Natacha Fontes, Alberto C. P. Dias, Rui M. Tavares, Maria J. Sousa, Alice Agasse, Serge Delrot, Hernâni Gerós, Biochemical changes throughout Grape Berry development and fruit and wine quality, Food, 1(1), 1-22 ©2007 Global Science Books.
2. Illustration from: Isak S. Pretorius, Conducting Wine Symphonics with the Aid of Yeast Genomics, Beverages, 2016, 2(4), 36.

Video Made By Our Friend

Our friend took this time to make a video of the vineyard and our friends which brought back a lot of wonderful memories.

Pruning the Chardonnay

This year, we are trying to do our pruning duties on the early side. We began on February 1 and had help from our friends who pruned the tops of the one year old canes for us and put us in a good place. We are now beginning the pruning and choosing this year's canes to lay down. Yesterday, we finished pruning 6 of the 8 rows of Chardonnay. At this time last year, we had just started the pruning duties.
Since we are the only ones working in the vineyard, we are practicing social distancing. Please, everyone be safe and contribute to the flattening of the curve!

2018 Château Yvonne La Folie

Last night, my husband made his famous eggplant parmigiana with two long Asian eggplants. He is known for this dish. My mother, who lives in Hawaii says that it is the best eggplant parmigiana that she has ever had, so when she came to visit us in May, 2019, she requested that my husband make this dish. He did not disappoint.
The beauty of this dish is that he makes all of the eggplant and we get to freeze what he doesn't turn into the evening meal. We were able to freeze 4 more servings for future use.

We had this 2018 Château Yvonne La Folie, a Cabernet Franc from the Loire to pair with the eggplant parmigiana. The color of the wine was very dark, inky purple in the glass. The body was of medium to medium heavy extraction. For a wine that is less than 2 years old, it had a very silky finish with very little tannins and balanced acidity. It paired very well with the tomato based meal.
This is the second of Château Yvonne's offerings that we have tasted. In December 2019, I blogged about 2018 Chateau Yvonne Saumur-Champigny L’ile Quatre Sous

La Folie comes from plots in the village of Champigny itself with vines ranging from 15-50 years in age, grown on clay and limestone soils. In 2007, Matthieu Vallée took over from Yvonne and Jean-François Lamunière who resurrected the ancient vineyard in 1997 with the help of Françoise Foucault. Matthieu Vallée decided to keep the name Chateau Yvonne in hommage to the incredible work done by the previous owners.

The grapes are hand harvested and fermented with native yeasts in 50 hl concrete vats. The fermentation lasts for 4 weeks then the wine is aged for 12 months in half 38 hl foudre and half in 4-5 year old barriques. The wine is bottled unfined and unfiltered with minimal sulfur.
References:
1. Coeur Wine Co., Château Yvonne.
2. The McCarus Beverage Company, Château Yvonne.

Vintage 2020: Pruning Time

We have been working in the vineyard since February 1, 2020, pruning the tendrils which is our first step in pruning. We learned from our experiences of last year that in order to speed up our pruning task, all the tendrils needed to be removed from the trellis wires as well as from each other. We finished this task on March 4.
As a comparison, in 2019, we were simultaneously cutting tendrils, pruning and laying down the canes. We began on March 18 and finished up on May 4, 2019. We were laying down the Chenin Blanc canes just a little before they entered budbreak.
We thought that we were cutting it too close so this year, we began our vineyard work on February 1. Despite our early start, Mother Nature has a few tricks up her sleeves because it has been a very warm winter so far and with spring coming in one week, the temperatures are not going to be cold for too long and we might be looking at an early budbreak.

This year, we are trying the Simonit & Sirch Pruning Technique, and tried that method on the Barbera. The Barbera was planted in 2017 and this year, we hope to lay down a few of the canes to see what kind of fruit develops. We are using a single guyot since the vines are only a meter apart from each other.
After pruning, we are applying a product called VitiSeal, to prevent bacterial and fungal intrusion into the pruning wound. It is a non-pesticidal, natural solution to grapevine trunk and related diseases. The VitiSeal looks a little like milk. We end up spraying the VitiSeal on the pruned areas.

Alsace Part 2: The Geology - Putting it All Together

Little did I know that when I said I would blog about the geology of the Alsace, that I was about to discover a wine region with one of the most diverse soil types of any wine region in the world. Along the way, I think I learned a lot about the early formation of our current continents. To recap, here is my geological journey so far:
I began my blogposts of the geology of the Alsace by showing a cartoon of The Layout of the Land as well as the various soil types that can be found in the Alsace wine regions. I could have/should have stopped there, but I wanted to know where the mosaic of soil types that exist in the Alsace came from. I learned that the Alsatian region was part of a graben system and I blogged about it in The Location of the Upper Rhine Graben in the context of the European Cenozoic Rift System, which formed in the late Eocene Epoch some 50 million years ago.
In the third blogpost on the geology of the Alsace, I narrowed the focus from the Upper Rhine Graben to The Vosges and the Black Forest Mountain. While the Upper Rhine Graben formed in the Eocene, the Vosges and the Black Forest uplift was of an even more recent event, occurring perhaps during the late Pliocene or the early Pleistocene Epochs (5.3 Ma).
All of these blogs were written to put into context, the prime focus which was the most recent post on geology, The Vosges Mountain Paleozoic Evolution. It is during this ancient time some 350 Ma that the diverse soil types were being formed. This blogpost showed in pictures the soils from the northern Vosges to the southern Vosges.
Here in a cartoon form is what I learned about the geology of the Alsace:^1,2

When putting the information of where and how the various soil types formed, we can update this picture which was part of the first blog on Alsace Part 2: The Geology - The Layout of the Land to include the impact of the soil on the style of wines being produced.¹

Next up on my discovery of the Alsace Wine Region, the history of the Alsace. Stay tuned!
Reference:
1. Vins Alsace, Remarkable Geology: A Mosaic of Unique Soils.
2. Michael Schafer Esq., The Amazing Alsace.
3. Jeanne Vidal, Albert Genter, Overview of naturally permeable fractured reservoirs in the central and southern Upper Rhine Graben: Insights from geothermal wells, Geothermics, 74 (2018) 57–73.
4. Y. Rotstein1, and M. Schaming, The Upper Rhine Graben (URG) revisited: Miocene transtension and transpression account for the observed first‐order structures, TECTONICS, VOL. 30, TC3007, doi:10.1029/2010TC002767, 2011.
5. Hinsken, Sebastian & Ustaszewski, Kamil & Wetzel, Andreas, (2007), Graben width controlling syn-rift sedimentation: the Palaeogene southern Upper Rhine Graben as an example, International Journal of Earth Sciences, 96, 979-1002, 10.1007/s00531-006-0162-y.

Just a Little Fun

Something a little light hearted for the blog today. A little change from the information dense blogs of late. Here is an awesome cork project for all of the corks you have accumulated. This is a cute wall decoration that lives at my sister-in-law’s home.
I’m inspired!

Simonit & Sirch Pruning Techniques

My husband has been investing a lot of time this winter in learning about a pruning technique called Simonit & Sirch. After 7 years of taking care of our grape vines, we have realized that pruning is a skill that is acquired through on the job training.
We have approximately 6,000 vines which means that we have 6,000 individuals each requiring it's own idiosyncratic handling during pruning.
Last year during pruning, we tried to ensure that our pruning did not lead to disease by "painting" the pruning wound with a sealant.
The Simonit & Sirch method of pruning aims to protect the pruned vines from trunk diseases and in the process extending the life of the vine. Their pruning method involves following the sap routes to reduce the probability of introducing infections. The vine develops a cone of desiccation as a reaction to being pruned inducing a necrosis that is 1.5 times longer than the diameter of the cut on the pruned spur or cane. So I believe that the pertinent advice here is to leave enough of the vine so that the cone of desiccation can form without impacting the living regions of the vine.

While my husband was doing his research, he came upon a blog written by Cameron Roucher, vineyard manager at Rathfinny, about being trained in the Simonit & Sirch technique and their implementation of the technique in their vineyard. We have communicated with Cameron over the years since we learned that they also had planted their vineyard with tall grafted vines so, when my husband sent Cameron an email, Cameron wrote right back and included some photos.

Every year we learn a little more about how to prune the vines so that they are healthy and produce new shoots for the following year. We will be trying the Simonit & Sirch method this year.
Reference:
1. Pruning With Regard to Sap Flux.