Wine Grape Growing, Production and Chemistry-Viticulture and Enology

Last week, I wrote an article asking my readers if they are an oenophile. Today, I am very delighted to feature a guest article about Viticulture and Enology from a guest writer who is an oenophile and a wine aficionado. Thank you, Frank for this very informative and excellent article on wine production.

Wine Grape Growing, Production and Chemistry by Frank Cabunoc, Guest Blogger
It is summer in California and it is time to go out and enjoy outdoor activities. One of our favorite places to visit is the Napa and Sonoma valley wineries to see the lush vineyards, wine production and wine tasting rooms. In wine tasting they teach you about the basics of smells, texture, color and about grape varieties, how wine is made, what wine goes with what food and exposes you to the culture surrounding wine. Try to visit various types of winemakers from the small ones to the prestigious vintners and learn about various ways they make wines and taste the variety of wines made from all the different places. In this article you will be exposed to what makes the taste of the wine from growing grapes, wine production and wine chemistry.

Grape Growing
The most important factors of wine grape growing are the annual life cycle of the vine, climate, terrain, vineyard management, pests and diseases, terroir, and planting grapes. Of these aspects, climate is one of the most important. Vineyards thrive best in moderate climates that are between 20 and 50 degrees Latitude on both sides of the Equator. These are mostly temperate countries such as areas of Southern Europe along the Mediterranean Sea and many places in the USA which includes California. In the southern hemisphere wine grapes flourish in Chile, Argentina, South Africa and Australia.

California has many varied terrains suited to a large number of varietals. It refers to the soil type as well as the local topography. Grape growing is affected by the composition, fertility and slope of the soil in a vineyard. When planting grapes, the grower must determine which grape varietal to plant based on the characteristics of the land. In California, root stocks and clones to be planted need to be chosen with great care, because wine grape growing is affected by many different factors.

Not all aspects of the grape growing process are left to nature. Vineyard management also has a deep impact on the finished product. Successful vineyard managers are knowledgeable with the physical aspects of their property, and make grape growing decisions accordingly. Grape growers constantly need to be on guard against pests and diseases. There are many strategies that are used to minimize these threats. For example, phylloxera can be controlled through grafting Vitis vinifera cuttings onto Native American root stocks. Some organic growers do not use pesticides and instead use other insects to control the vineyard pests. They grow other plants beside the vineyards where the predator insects propagate and protect the wine grapes by preying on the pests.


Throughout Europe, specific varietals have been grown in certain regions for centuries. After growing grapes in the same place for many years, managers became aware of the aspects of their land that make it unique. Grape vines particularly respond to localized features that are inherent in the vineyard. This complicated notion is known as terroir.
The annual life cycle of the vine lasts from early spring to late fall. Several wine grape growing regions in California Wine Country have very long growing seasons, especially in San Luis Obispo and Santa Barbara Counties.

Wine Production
Wine Production was first seen around 8,000 years ago in Georgia, in the Caucasus area. But it wasn’t until 1857 that French chemist Louis Pasteur correctly described the science behind fermentation and Wine Production. Because crushed grapes contain all that is needed to create wine, ancient wine producers simply allowed nature to take its course. As time went on, people realized that by intervening at certain times of wine production, they could make a wine with more predictable characteristics. At present, during the primary fermentation, cultured yeast is added to feed on the grape sugars and let yeast cells multiply, producing carbon dioxide gas and alcohol.

One of the first things winemakers realized was that red wine production required that the grapes be fermented in contact with their skins. This gives the wine color and body for red wines. In contrast, most white wine production does not occur in contact with the grape skins. White wines are valued for their fresh fruit characteristics, and skin contact would impart unwanted bitter tannins.

Sparkling wine or Champagne production is a complex process that has been honed for centuries in the Champagne region of France. Several California wine producers also use these traditional wine production methods. Wine undergoes a second fermentation in the bottle, trapping carbon dioxide and giving it bubbles.

The fortified wines have a spirit infused on them which is usually Brandy. Fortified wine production can make either sweet or dry wines. If the spirit is added during fermentation, some residual sugar will remain in the wine and a Port will result. If the spirit is added at the end of fermentation, a dry Sherry will be made.

There are a number of sweet wine styles produced in California using many different wine production techniques. Grapes affected by botrytis cinerea or “noble rot” make deeply concentrated wines with high residual sugar. Another technique vintners can use is harvesting the grapes very late in the season when they are already very ripe and sweet and using them for sweet wine production.

Wine Chemistry
Wine chemistry explains the flavor, balance, color, stability that was once only possible through subjective description. Understanding the principles of wine chemistry will open your eyes to a new level of wine appreciation. Wine chemistry can be as simple or complex as you want. There is always another level of depth, from the chemical components of wine in taste perception, to the balance of various phenols, acids and sugars. This balance is:

Sweet Taste (sugars + alcohols) <= => Acid Taste (acids) + Bitter Taste (phenols)

The phenols are a class of molecules that account for the taste, smell, medical benefits and diversity of wine. Because wine is 95% water and alcohol, the differences found in wine are derived from that 5%. Phenols give wines their distinguishing characteristics; and are broken down into flavanoids and non-flavanoids.

Flavanoids and non-flavanoids are wine chemicals that have a profound impact on wine quality, color and flavor. These molecules are largely influenced by acidity, and interact with acids to form complicated, yet important molecules. Acidity may be the most important aspect of wine chemistry.

The majority of these acids are produced naturally by the vines, but their relative levels are adjusted based on a multitude of factors. One of them is the alcohol content, which is an indication of the sugar in wine. Sugar is converted to alcohol by fermentation; thus the sugars present and their relative concentrations in the grapes are important for the overall character of the wine’s chemistry.

Balance in wine allows the fruit flavors of the varietal to show through. The chemical nature of varietal aromas gives insight into why certain wines taste the way they do. The wine chemistry explains why you love a certain varietal, and don’t care for others.

Note: This a second article by Guest Blogger, Mr. Frank Cabunoc. He is from Quezon City, Philippines. Frank and his wife Mildred reside in Fairfield, California.
Frank, Thanks a million again for a well written article on the science of Viticulture and Enology.