(Sex) In The Vineyard

June 24, 2013

When is a cluster not yet a cluster?

As springtime weather permeates the Napa Valley with consistent warmth and blankets the vineyards in daily sunshine, the vines react and begin to reveal early clues about their future grape crop. The steady warm weather coaxes the vine into producing an abundance of leaves while at the same time exposing its most precious asset, the flower cluster. But how does a flower cluster transform into a grape cluster?

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Flower cluster that looks like baby grape cluster.

 

At this early stage in the life of the flower cluster, the rachis (or structural component of the cluster) is dotted with hundreds of tiny green bee bee-sized spheres. Over time, the cells within these bee bees begin to differentiate into unique and essential components of the grape flower, including male and female reproductive organs necessary for pollination. Six to eight weeks after leafing begins, the development of these flower parts is complete and the flowers are ready to bloom. The creation of a grape flower is a delicate process influenced by many factors including plant nutrition and weather. Cold temperatures in spring will delay development, and rainy or cold weather can hinder the process by not allowing for proper pollination, often referred to as “shatter”.

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Maturing grape cluster

 

Once the grape flower has developed and its reproductive organs have been properly exposed (I apologize for the near x-rated description, but it’s just biology!), pollination can occur. Without pollination, grapes would never develop on the vine so the whole global wine industry relies on this fragile process that occurs over only a handful of days). It is unclear what method the grape flowers use to become pollinated but it is believed that self-pollination is the most common process followed by wind and insects each playing a minor role. If temperatures drop below 60º F, pollination will be greatly reduced and if temperatures rise above 104º F, pollination will also be inhibited. Clearly the environment must be in the right “mood” for grapes to be created, so hopefully this year Mother Nature has turned on her version of Tom Jones or Barry White in the vineyards and makes the magic happen!

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Blogger and Assistant Winemaker, Jason Gerard.

Jason

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Pruning decisions are perennial choices made by every vineyard manager across the globe. With a few years behind it now, Kerry’s Vineyard (www.kerrysvineyard.com) is graduating from vinifera adolescence and transitioning into adulthood.  As the vineyard solidifies into a relatively permanent yearly routine, a very important decision needs to be made regarding the training system of the vine.

The inherent nature of a vine and its chaotic growth patterns allows it to be sculpted into an infinite variety of somatic plant structures. There is no one right way to train a vine, but through cultural influence, local trends, experimental research and historical practices, certain standards of training have emerged. In Napa Valley, there are three main styles of pruning in the vineyard: head-trained, cordon, and cane pruning.

Head-training

Head-training

Cane

Cane

Cordon

Cordon

 

This year, in Kerry’s Vineyard, it is time to decide between either cordon or cane pruned training (if we wanted to go head trained, that decision must be made almost immediately after planting the vineyard, whereas the first few years of cordon or cane pruning are the same).

To put it simply, the arms of the vine that run parallel to the ground eventually produce many new shoots which will be the source of the individual grape clusters. In cordon training, the parallel arms are permanent structures on the vine and remain year after year whereas in cane pruning, the parallel arms are formed every year by leaving one-year old shoots leftover from the previous harvest.The main difference between the two styles is that cane pruning will yield slightly more fruit.

Because Cabernet Sauvignon is a lower yield variety and because Kerry’s Vineyard is on a hillside (as opposed to the valley floor), we have chosen to go with cane pruning for the Estate vineyard. As you drive up and down Hwy 29 and Silverado Trail in Napa Valley, you will see mostly cordon trained vineyards. Because these vineyards are planted on the valley floor, which is rich in nutrients and water, the vineyard managers are hoping to lower the yields of these vines by using the cordon training method. This will in turn help to balance the vine and produce better quality grapes. However, on a hillside vineyard, nutrients can be limited and water tends to drain very quickly, both factors that lead to lower yields on the vine. To compensate, the technique of cane pruning is utilized. Another benefit to cane pruning is it less harsh on the vine itself. With cordon pruning, each new shoot (usually 8 to a side for a total of 16) are pruned every year leaving the vine with many pruning scars. This leaves the vine much more susceptible to infections (such as Eutypa, described earlier). Because of this, excessive pruning can lessen the lifespan and efficiency of an individual vine.

So, as you can see, many key decisions are made when planting a vineyard and lots of work goes into maintaining a vineyard as well…..and we have barely even scratched the surface of the complexities that go into creating and maintaining a vineyard that will produce quality fruit year after year. It’s a good thing that we enjoy it so much!

Jason

Weather in the Vineyard

June 21, 2011

Is the weather wacky or is it just us?

 

Global warming?

It is no secret that California boasts some of the greatest year round weather in the U.S. if not the world. Mild winters and beautiful, sunny summer coupled with lavish leaf-filled falls and flowery lush springs create a temporal utopia for both flora and fauna to flourish. So what happens when this paradigm of gorgeous weather fails us? What happens when the sky brings hail and CalTrans brings chain control in the month of June? Is it global warming? Climate change? La Nina or El Nino? The Rapture?…..is it some other buzzword induced catastrophe that has yet to be named?

The Rapture

In my mind it is all of these things and none of them (well maybe not the rapture). The global weather fluctuations are a complex and dynamic process, so much so that even experts struggle to understand the nuanced relationship between our atmosphere and our lives. It is human nature to over simplify such complexities:  give it a name and move on in an attempt to pretend like we know what’s really going on….when in fact, deep down, we do not. I believe we understand the multi-faceted complexity of weather to a degree but we cannot kid ourselves into believing we truly grasp the dynamics of global weather patterns.

Rain in June?

Despite our unceasing faith in predictable California weather, this spring has shaken our confidence.  So, what is the bottom line? For grape growers, gardeners and other farmers, the weather is the truth we live by. We can only wait and react to the multifarious world around us. Yes, rain and hail and wind in June is out of the ordinary but as grape growers and winemakers we don’t have the luxury of asking why? We ask, how will this effect our crop?…..Hail can (and did) damage leaves in the vineyards, this leads to decreased photosynthesis and susceptibility to bugs and disease. Rain can be a good thing bringing more life-giving water to the vines but too much this time of year can lead to mildew growing on the vines which can damage and kill the essential green growth and basically cripple the vine and its ability to produce fresh and beautiful grapes necessary for making great wines. Mildew can also grow on the grapes themselves rendering them completely useless for wine production. Too much water trapped in poorly drained soils can also lead to excessive green growth on the vines which can lead to over cropping and difficulties in ripening.

It also appears we may be heading into a second consecutive cool spring and summer time (not today, however;-) which, as we saw last year, can make it challenging to get all the grapes to the appropriate ripeness before the winter rains come back in October and November.

While I enjoy pondering and debating the deeper meanings and explanations of

Jason pondering the future.

the odd weather we are experiencing right now, when it comes to winemaking and grape growing, I remain concerned and observant, ready to adjust vineyard practices and winemaking techniques in order to maximize the quality of wine we are going to produce when fall comes back around. Despite the adversity brought about by unusual weather patterns over the last several growing seasons, we are still farmers and producers of crop based commodities, and like those who have come before us throughout human history, we will adapt as we always have.           Jason Gerard

Around the beginning of September, I asked Jason Gerard, our associate winemaker who also happens to be a good writer, to write a blog about what was happening in the vineyard.  Just looking out the window, I could see the lush green of our Kerry’s Vineyard but what was going on under those canopied rows?  Here’s what he had to say:

A walk through the vineyard reveals grape clusters with a mosaic of green and purple berries. Just how many of these berries are purple gives us a good indication of how far away we are from harvesting the fruits of our labor. Of course every vineyard is at a different stage in its grape maturity as many factors play into when a grape will be ready to be picked. Location, varietal, rootstock are just to name a few of the variables that makes every vineyard block unique and therefore each will have a different optimal day for harvesting. For example, at the same vineyard location, on nearly identical soils, we have a block of Cabernet Sauvignon that is 100% through veraison (the word used to describe the coloring process of the grapes from green and immature to purple and mature) and another block right

Cab grapes in Kerry's Vineyard

Veraison in early September

next to it of Petit Verdot which is at 75% veraison. This tells us as winemakers that the Cab will be picked before the Petit Verdot. This of course helps us in our logistical planning for the harvest. Multiply this many-fold and you begin to understand the complexities of planning something that is as dynamic as the grape harvest.

At Tom Eddy Wines, we bring in fruit to the winery from several different vineyards from all over Napa Valley. At this time of year we are constantly traveling to all these vineyards to assess the current status of grape maturity. There are several ways in which we do this both scientific and instinctual in nature. The most obvious way of determining berry ripeness is through the good old-fashioned taste test. However, we also like to take a more scientific approach by testing some basic berry chemistry in the Tom Eddy Laboratory or what some commonly refer to as the kitchen….

How this works is, Tom or I will randomly select approximately 100 berries from any given vineyard and bring them back to the kitchen, which, literally is a kitchen but with a few not so common kitchen upgrades that allow me to do some basic chemistry. The 100 berry sample is crushed and the juice that is produced is collected in a beaker. There are three different numerical values that are obtained from this juice sample that give us insight into the maturity level of the grape: brix, Total Acidity and pH.

Cabernet ripening in Kerry's Vineyard

Maturing grapes in Kerry's Vineyard

As a grape matures to ripeness, it accumulates sugar through photosynthesis. The amount of sugar accumulated is measured in Brix. Using a refractometer, a couple of drops of the crushed sample juice are placed on the lens of the device. Based on the density of the juice, the refractometer will display a brix value which is very similar to percent sugar but based on density. Once the brix value is around 25 (not exactly 25% but very close), we know the grapes have accumulated enough sugar to be considered ripe for the picking. However, two other factors are also evaluated as brix does not tell the whole story.

The Total Acidity and pH values are closely related and also give great insight into grape maturity. As a berry matures the total acidity level drops. If you ever get a chance to try an unripe grape, you will notice an intense sour quality. This is due to a high level of total acidity and makes the grapes at this stage, almost unbearably sour and inedible. However, as the acidity drops and the brix increases due to sugar levels increasing, these two ripening factors come into balance. The key to picking the fruit at the right time is all based on the right balance of sweetness (determined by brix) and sourness (determined by Total Acidity). This is why it is so critical to check the vineyards constantly at this time of year because the chemistry within the fruit is constantly changing and evolving towards ripeness and picking the grapes within the right window of time can mean the difference between amazing wine or unbalanced wine.

pH is the final test to determine the acid level and therefore the maturity level of the crushed grape juice. This test is based on the total number of Hydrogen ions in the juice which is an inverse logarithmic scale so as the Total Acidity drops, the pH value goes up. In general the pH range for ripe Cabernet is between 3.50 and 3.80. (As a frame of reference, Hydrochloric acid is very acidic at about pH 1.0 and our stomachs are also quite acidic at 2.0. Water is generally neutral at pH 7.0)

So as the floor and counters of the Tom Eddy kitchen laboratory get sticky with the analysis of grape juice, we know we are inching closer to that fateful first day of harvest. Are we ready for the logistical chaos that is harvest? Of course we are! This is what we live for!                                            Jason

The 2010 Harvest Compared to 1998
(this was written by Tom on August 4, 2010)

Some folks out there are comparing the 1998 harvest to this year.  How can this be?  Well, for starters, there are some similarities with the weather.  However, the similarities may not be that great.  The harvest season of 1998 was unique and really not like what we’ve seen so far in 2010.

During the 1998 season there was a wild heat spell early on in June that caused major damage to the berries, and there was late season rain.  Both occurrences blocked the vine’s ability to ripen fruit.  We have different challenges in 2010.  This year has been one of the coldest and wettest springs we’ve ever had.  The summer has also been cool on a relative scale.  We have had only 5 days above 90F thus far, and typically, we might have 50 plus days of 90F plus heat by this time.  So, the result will be that we’ll be three weeks late……………but, here’s the kicker.  The conditions for Cabernet quality is still perfect!

Cabernet Sauvignon wants early morning fog, and warm days approaching 85-90F, but not hot!  Guess what, that’s what we’ve had!  Yes, we will be three weeks late but the slow maturity of Cabernet Sauvignon on into October should produce stellar wines of solid acid, bright fruit, and big, classically structured tannins!   The lone caveat is that growing grapes under cooler and wetter conditions (more similar to Bordeaux) requires greater attention to solid management practices, including thinning to smaller crops and leafing early for good air flow to avoid mildew and allow for good light penetration.

We all remember the media thrashing the 1998 vintage six months after it was in the barrel saying it was light and thin. Now, of course, critics are suggesting the vintage was a bit special and not so bad.  Come next spring for the 2010, we’ll see.                                                                           Tom