From the Seed to the Glass - Part I

It is a special night!  You are celebrating a monumental life event - maybe an anniversary?  A birthday? Or, it's just Tuesday and you feel like enjoying a nice glass of wine!  You may have a few bottles on hand, or you may have picked a bottle up that day.  But where did it come from?  I don't mean where in your house or what store or even what winery!  I mean, how does wine get from a seed to a grape to a bottle to a store and, finally, to your glass?  This blog entry will be Part I in a two part series to provide an overview of where your wine REALLY comes from.

So, as to use the proper lingo, another word for grapevine is Vitis.  As Wikipedia states, "Vitis is about 60 species of vining plants in the flowering plant family Vitaceae."  Interestingly, Winpros.org tells us that wine seeds do not necessarily grow into the desired type of varietal.  The modern wine vine, is a result of a cutting (also known as slip or scion) of the plant that one actually plans to grow.  This statement very much simplifies the process, as much more goes into preparing the cutting to actually be planted to bear fruit.  Proper soil, drainage and weather conditions are imperative for young vines to grow.

wikipedia.org

After a vine has developed, it is important that the vine be manicured and pruned.  Interesting, Winepros.org tells us that one vine, if left to its own devices, could cover an acre of ground!  Pruning is the cutting and shaping of the cordon or "arms" of the grapevine.  This will determined the number of buds that will become grape clusters.  France's AOC regulations actually outline the exact number of buds allowed!  Modern vines are pruned in different ways, depending on the area, the varietal and other factors.  It must be done in such a way that there is not too much or too little.  Pruning actually trains the vine to grow in certain ways.

Along with pruning comes trellising.  The trellis refers to the actual stakes, posts, wires or other structures to which the grapevine is attached.  Trellises are not required, but often used to train the vine.  Typically, the vine training system used will often take the name of the trellis utilized.  Trellises can differ by geography, harvesting methods, variety, as well as other factors.  The different configurations affect sun and wind exposure, as well as accessibility of fruit clusters to facilitate hand or machine harvesting.

Photo by Mary Jo Guinn

Not only is keeping the vine manicured important, but also there are a hosts of enemies that could destroy vines if left untreated.  A few examples are insects, fungi, moles and gophers, as well as other animals and birds, with birds causing the most crop loss and fruit damage.  Phylloxera is an insect that many have heard about as an enemy to wine vines and grapes.  In the late 19th century, Phylloxera epidemic destroyed most of the wine grape vineyards in Europe, most notably in France.  In modern times, hybridization has created a barrier to Phylloxera.  Interesting, most native American grapes are naturally resistant to Phylloxera.

The first step in the growth of the actual grapes is bud break.  Buds appear on the vines in the spring.  In the Northern Hemisphere, this begins around March and in September in the Southern Hemisphere.  The buds are located between the vine's stem and the petiole, or leaf stem.  Some early budding varietals can be at risk for premature bud break.  This is hazardous situation because the young shoots would then be vulnerable to frost damage.  Heaters or wind circulators are actually set up to prevent cold air from settling on vines.

Kenbrownwines.com

Next is vine flowering.  The shoots where the grapes will eventually grow from, burst forth and flowers then form on them.  This occurs approximately 40 to 80 days after bud break.  Small flower clusters appear on the tips of the shoots.  A few weeks later, the flowers start to grow in size and individual flowers can be seen.  This is the time when pollination and fertilization of the vine takes place with the result being a grape berry.  Each grape berry contains one to four seeds.

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Third, is the fruit set.  The fertilized flower produces a seed and forms a green grape berry around the seed to protect it.  This stage occurs almost immediately after flowering.  This stage is critical, as it determines potential crop yield.  The average percentage of fertilized flowers ranges from 30 to 60.

crawfordbeck.com

The next step is veraison.  This is when the grape changes color from green to either yellow or purple as it ripens in the sunlight.  This stage takes place around 40-50 days after fruit set.  The colors of the grapes change due to the chlorophyll in the berries skin being replaced by anthocyanins in red wine grapes and carotenoids in white wine grapes.  Berries grow dramatically in the first six days of veraison as they accumulate glucose and fructose.  This process is not uniform with the berries.

twomountainwinery.com

Veraison then moves into ripening.  The grape ripens on the vine, in the sun, developing sugars.  As the grapes ripen, sugars and pH increase as acids (i.e. Malic Acid) decrease.  Tannins and other phenolics are developed that affect the flavors and aromas of the wine.

Finally, the last step in the preparation of the grape is harvest.  This is a wonderful time, where the grape is picked at its peak time.  The grapes are either hand or machine picked and transported to the winery to begin the winemaking process.  The time the grapes are harvested depends on ripeness.  Following the harvest, the vines continue photosynthesis, creating carbohydrate reserves to store in the vine's roots and trunks.  It will do this until an appropriate level of reserves have been stored.   Some wines are referred to as "late harvest" wines, which allows the sugar to build up even more.  These are typically dessert wines, such as a late harvest Riesling.

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Stay tuned for Part II of this blog when we discuss how the grapes move from harvest to your glass!

Cheers!
Mary Jo