Terroir is the collective term for all the features intrinsic to the place wine grapes are grown. It can be equated to an ecosystem and includes all the minutiae of climate, soil, and topography that impact the characteristics of wine grapes.
Terroir is the foundation on which wine builds its unique character.
An introduction to Terroir
Good wine provides a little something for all the senses, from the earthy, peppery notes in full-bodied Australian Cabernet Sauvignon to the subtle scent of a faded rose in an elegant French Pinot Noir.
Whether the winemaker is following old-world traditions or using every trick modern science provides, it starts with the qualities within the wine grapes, and those are acquired from the vineyard where the grapes are grown.
The elements that make up the grape growing environment of a vineyard are embodied in the term terroir.
Why should we care about Terroir?
One of the joys of wine appreciation is identifying the specific characteristics of a wine that compliments a meal or simply appeals to you, and then recognizing it again in different wines.
Tracking down comparable wines can very satisfying. Knowing how terroir is responsible for those characteristics improves your ability to ferret out similar wine from around the world. It’s like a map you can navigate using your personal taste as a compass.
What is Terroir?
Terroir can be equated to an ecosystem. It is intrinsic to where the grapes are grown. These are characteristics that can’t be changed within one season.
Under terroir, we include climate, soil, and topography, factors that directly impact the quality of wine grapes. Less evident would be including something like the surrounding flora. For example, there are vineyards in Australia and California that are surrounded by eucalyptus trees, and the wine from these vineyards can have hints of eucalyptus.
Terroir can be considered at various levels; macro - a large wine region like Rioja, Spain, meso - a sub-region such as Rioja Baja, and micro - a specific vineyard or even a single row of grapevines.
Terroir, for the Musical Ear
The notes terroir leaves on wine are a frequent source of debate. Wine lovers can argue about terroir for hours, which seems a bit excessive, but it is hard not to be intrigued.
Good wine is made from just one ingredient: grapes. All wine grapes have skins, stems, pips, yeast, juice, and sugar, and winemaking is simple enough; crush the grapes, ferment it, age it, and put it in a bottle. So, why is there an infinite array of subtle variations? A good vintner is part of the answer, but the best winemaker can’t construct a great wine out of bad grapes, any more than a pianist can coax great music out of a mistuned piano.
Terroir is about properly tuned grapes.
How does Terroir impact the quality of wine?
The answer is through chemistry. The complexity, balance, and other attributes of a wine are developed through the fermentation of grape juice and refined by aging, so the compounds found in wine are dependent on the compounds found in grapes, which is a function of the terroir.
Soil, Tough Love
Sometimes it takes rough treatment to develop character, and wine grapes, like people, need the challenge to help them develop. Give them an easy, pampered life, and they get dull and flabby.
Grapevines are hardy. Where other plants struggle, wine grapes shine. For winemaking, grapevines under moderate amounts of stress produce better-balanced grapes, albeit with lower yields.
Chemicals in soil
Grapevines are relatively undemanding as far as soil chemical composition and nutrients are concerned. Vineyards are often low on organic matter and nutrition. Too much nitrogen, for example, encourages shoots, which may later need to be reduced to allow more light in to reduce the risk of rot. (See Canopy Management)
Barren ground forces the grape to push roots deep. Through the process of ion exchange, the fine hairlike roots on grapevines absorb mineral elements. Copper, iron, and magnesium, especially, express themselves in the aroma of the wine.
Physical Characteristics of Soil
Physical characteristics and microclimates have a bigger impact on grape quality than chemical composition.
The ability of the ground to regulate the water supply is a crucial factor. Good drainage allows rain to disperse quickly, helping maintain the perpetual water restriction that promotes slow vine growth. This makes for small berries with better grape skin to fruit flesh balance, plus it fosters tannins and boosts color yield.
Heat retention is also important. Dark soil absorbs heat during the day and releases it at night. Stoney vineyards produce the same effect. Warm soils help late-ripening grapes to ripen. Cool soils, on the other hand, reduces the risk of overripening to early ripening grapes.
Climate
Almost all wine-producing grapes are grown in the band between 30°- and 50°-degrees latitude on either side of the equator. There’s quite a diversity of wine regions within that band, and a variety of challenges for vintners at the edges. Three important climate factors are temperature, sunlight, and rain.
Temperature
Generally, too cool and grapes have trouble ripening. Grapes that just make it to ripeness produce acidic, low alcohol wine. Too hot and the grapes quickly overripen, producing wine lacking acidity and elegance.
Extreme weather notwithstanding, wine grapes are not too fussy during the main growing season. However, when the end goal is quality wine, there are two periods when temperatures play a big role: first during the spring, and again before the harvest.
When average temperatures in the spring get to 10 °C (50 °F), shoots will form. If there is a false spring, or a late frost, and temperatures dropping to -1 °C (30 °F), it can cause frost damage.
The ideal temperature for vine flowering is between 20°C (68 °F) and 25 °C (77 °F), whereas temperatures below 15 °C (60 °F) or above 35 °C (95 °F) will prevent flowering.
In the final ripening period - the month before harvest - high temperatures above 21 °C (70 °F) can reduce acidity too quickly, leaving the wine flat. With temperatures below 15 °C (60 °F) the wine grapes will struggle to get ripe, and the wine can be too acidic.
Sunlight
Vineyards growing on gentle slopes rising from peaceful blue lakes are not there simply to provide lovely photo opportunities. Vineyards are planted on slopes to maximize sunlight, and the light reflected from lakes and rivers can help vineyards in cooler regions.
Grape leaves need sunlight for photosynthesis to form sugar, which is stored in the grapes. The intensity and duration of sunlight affect the sugar levels (Brix) in a grape. The sugar in the grape determines, among other things, the alcohol content and residual sugar in the finished wine.
Rain
Too much or too little rain can be bad news for wine grapes.
Too much rain during the main growing period, generally between April and October in the northern hemisphere, will produce too much foliage and swell, or even split, the grapes. This is one reason well-draining soil is desirable.
Likewise, too much moisture in a vineyard can lead to various problems, including mold, mildew, and rot.
On the other side, not enough rain in the summer can stress the vines and stop photosynthesis which impacts sugar levels in the grape. Using modern irrigation methods to keep grapes healthy and unstressed is an advantage a “new world” vintner has over “old world” producers, who may face restrictions from official wine classifications.
Final Word on Terroir
The term terroir is simple enough, but the more you scrutinize it, the harder it is to pin down.
The delicate interplay of countless components can lead to two of the same grapes growing just meters apart - in the hands of the same winemaker - resulting in completely different wines.
Terroir determines much of a wine's character and knowing what you like, terroir is a good starting point when looking for a wine to enjoy.