The grapes that make a particular wine dictate the general structure of that wine and how it will respond to everything the winemaker and viticulturist does to it. If a wine is white, odds are that it came from white grapes; if it is red or pink, that’s because the wine came from red/black grapes. How did it smell? Herbal, Floral, Fruity, Earthy? Whichever, those aromas come mainly from the grapes.
The specific grape variety (or varieties) is primarily responsible for the sensory traits the wine offers – from its appearance, aromas, flavors, and alcohol-tannin-acidity profile. How the grape grows – the amount of sunshine and moisture they receive, and how ripe they are when harvested is also a factor. So can winemaking techniques, such as oak aging, maturation, fermentation. Each type or variety reacts differently to the viticulture and winemaking employed.
By grape variety, I mean the fruit of a specific type of grapevine, such as Chardonnay and Merlot. A variety is a subdivision of a species. Most of the world’s wine are made from grape varieties that belong to the species vinifera – itself a subdivision of the genus Vitis. The species originated in Europe and western Asia; other distinct species of Vitis are native to North America.
Within the genus Vitis and species vinifera, there are as many as 10,000 varieties of wine grapes. If wine from every one of these varieties were commercially available and you drank a different one every day, it would take you more than 27 years to experience them all.
An extremely adventurous grape nut who has plenty of free time to explore the back roads of Spain, Portugal, Italy, and Greece might encounter over 2,000 different grape varieties. The grape varieties you come across during your normal lifetime may be fewer than 50.
How grapes vary?
The traits fall into two categories – I like to say personality traits and performance factors. Personality are the traits of the fruit itself – its flavors. Performance factors refer to how the grapevine grows, how the fruit ripens, etc… Skin color is the most obvious – either a white variety or red (or black) one when they are ripe (grapes have different colors when unripe). A few red-skinned grapes have red pulp, i.e. Saperavi, rather than white, but almost all red grapes have white pulp. Within the white and red categories, each grape variety has its own hue.
Aromatic compounds – some grapes like Muscat contribute floral aromas and flavors to their wines while others like Sauvignon Blanc adds herbaceous notes or fruity character (Riesling). Some grapes have neutral aromas and flavors (Chardonnay and Pinot Grigio), therefore, make fairly neutral wines.
Acidity Levels – some grapes have naturally higher acid levels than others, which makes for crisper, leaner wines. Acidity is sensed on the sides of your mouth. Think of biting into a lemon (citric acid).
Thickness of skin and size of individual grapes (berries) – black grapes with thick skins naturally have more tannin than those with thin skins. Ditto for small-berried varieties compared to large-berried varieties because of their skin-to-juice ratio is higher. More tannin in grapes leads to firmer, more tannic red wine. A Cabernet Sauvignon wine is usually more tannic and slightly lower in alcohol than a Merlot wine because that’s the nature of those two grapes. Tannin is a bitter compound found in mostly the skins (more in red/black vs. white grapes), but also in seeds and stems. Its the sensation that makes your mouth pucker.
How a particular grape variety performs in nature is crucial to the grape grower because the vine’s growth patterns determine how easy or difficult that variety will be to cultivate in a specific location. How much time does it need to ripen based on climate and growing season? How dense and compact the grape bunches are depending on climate? and How much vegetation does it have, soil, leaves, shoots, etc…? Soil is paramount, whether it be clay, slate, limestone, gravel, chalk, stones, and loam. It provides nutrition for the vine, influence temperature of vineyard, and water management system for plant. Ideally, Chardonnay in limestone or chalk, Cabernet Sauvignon in gravel, Pinot Noir in limestone, and Riesling in slate.
The reasons some grape varieties perform great in certain places and make excellent wine comes down to the amount of heat, cold, wind, rain (or lack of it), slant of sun on hillside or plateau. No two vineyards in the world are exactly alike or to use a French term – terroir (translates to sense of place).
That’s it for Part 1. Didn’t want to overwhelm you Skip and others. Part 2 will focus on more specific grape varietals. Enjoy!