Learning About Wine: Part 3

On Grape Growing

Wine grapes don't grow everywhere, they are fickle when it comes to their favorite spots and where they take root makes a substantial difference in the final style of wine produced.

I am covering the wine grape growing environment including what grapes require to grow their best, what makes certain region better for winemaking, what to expect from grapes depending on climate, and the stages of grape growing!

 For grapes to grow, a vine needs sufficient heat, sunlight, nutrients, and water. If too little of any of these, the vine may die and with too much of these, the vine can produce grapes that are unbalanced. See more details below:  

Heat: If the temperature falls below 50F, it is too cold for the vine to grow. Vines go dormant in winter and start to perk up and begin to bud in the spring when temperatures start to rise. If there is too much heat, the sugars in the grape increase, while the acid falls dramatically resulting in an overly ripe/jammy/cooked fruit character and flabby (acids are important in the overall balance of the final wine).

Sunlight: Sunlight is required for photosynthesis. Photosynthesis in grape vines is necessary for the production of sugar, and sugar-based elements that give grapes their color and flavor. It is a biochemical reaction which combines water and carbon dioxide using the energy of the sun to form sugars in the grape vines. In some extreme cases, intense sunlight can cause sunburn on the grapes (resulting in bitter flavors) so some wine growers will use the leaves of the vine to shade and protect grape clusters. 

Nutrients: Nutrients are an important factor to grow grapes and affect both the number of grapes produced by a single vine as well as influence the grape quality. The main nutrients a vine needs are Nitrogen, Potassium, Phosphorus, Calcium and Magnesium. The vine acquires these nutrients from the soil. If there are too many nutrients in the soil, the vine will produce a lot of greenery resulting in grapes with little concentration of sugars and acids.

Water: The vine needs water to help with photosynthesis and to swell the grapes up to a perfect, juicy, ripe plumpness. Rainfall is the most important source of water. In dry regions — when local laws permit — irrigation and sprinklers can be used to ensure the vine receives sufficient water. If there is too much water (in addition to nutrients), grapes can become diluted in flavor, sugars, and acids OR can be prone to water logged soils that can cause damage to the vines roots or increase disease pressure.

 Climate

In general, year-round weather conditions are referred to as the climate.  Winemakers know that wine grapes grow best in climates that aren’t too tropical, too arid, or too cold! Most suitable climates are found between 30° – 50° latitudes, both north and south. This means countries like Australia, Argentina and South Africa in the Southern hemisphere, and more well known growing areas like the USA, France, Italy and Greece in the Northern Hemisphere.

Cooler, dry climates produce higher acid wines (“crisp”) with fresher fruit flavors, whereas warm climates tend to producer lower acid, higher alcohol wines that have a fuller body with riper fruit flavors.

Cool Climate

Regions with an average growing season temperature below 16.5℃ are generally classified as cool climates. These would be regions such as Mosel (Germany), Niagara Peninsula (Canada), Tasmania (Australia), and Chablis (France).

 Wines from cooler climates tend to be fresher with higher acidity, lower alcohol, lighter in body and focused on clean pure flavors. Some famous grapes and styles that perform particularly well are Riesling, Cabernet Franc, crisp Chardonnay styles (such as Chablis), structured Pinot Noir, and many sparkling wine styles.

Moderate Climate

 Moderate climates include regions with an average growing season temperature between 16.5℃ and 21℃. These include regions like such as Oregon (USA), Adelaide Hills (South Australia), Margaret River (Western Australia), Bordeaux (France) and Piemonte (Italy), and the Central Valley (Chile).

Moderate climates have more heat to grow certain grape types that cooler regions are too cold to fully ripen. They generally produce wines that are ripe, juicy and medium in body. Grapes that perform well in moderate climates include Syrah, Sauvignon Blanc, Cabernet Sauvignon and Merlot.

Warm/Hot Climate

 Warm climate regions generally have an average growing season temperature above 21℃ such as the Barossa Valley (Southern Australia), Napa Valley (USA), Mendoza (Argentina), and regions in Sicily & Puglia.

Warmer conditions often lead to the boldest and fullest bodied wines. They often have riper fruit flavors (instead of clean or crunchy fruits, more developed and sometimes even jammy), higher alcohol, softer acidity, and a fuller mouthfeel.

Grapes like Nero d'Avola, Grenache, Malbec, Primitivo/Zinfandel and Viognier do well here, however Cabernet Sauvignon, Chardonnay and Shiraz also have famous and well-loved warm climate expressions. 

CLIMATIC Factors

Beyond the overarching climate of a region location, the exact planting of a vineyard is a highly considered thing and there are a few factors at play like soil type, drainage and weather conditions, as well as site-specific climatic factors such as altitude, latitude, aspect, proximity to large bodies of water and wind patterns (think La Nina vs El Nino). This is complicated as these climactic factors can provide cooling or warming influences in places that are considered cool, moderate, or warm depending on the factor itself!

Altitude: The temperature becomes cooler as altitude increases. 

Latitude: Temperatures are warmer closer to the equator and cooler closer to the Poles.

Aspect & Slope: Vines on a slope facing the sun get more heat and light. In the Northern hemisphere this means that south-facing slopes get more sunlight, whereas in the Southern hemisphere, north-facing slopes will get the most sunlight. 

Proximity to Water: Cold ocean currents can have a cooling effect on coastal regions (South Africa). Warm ocean currents can have the opposite effect (Bordeaux). In other areas with close proximity to the ocean, lakes, or rivers, a temperature moderating effect can occur. Water can moderate temperatures during the night and day, providing cooling breezes during the day, and temperature moderating warmth in the evenings. 

Wind Patterns: can provide cooling or warming influences, can increase evapotranspiration resulting in water stress, strong winds can stop photosynthesis or disrupt flowering and fruit set.

The Vine Cycle

Growing grapes is full of interesting quirks, amazing skills, knowing when to let Mother Nature take the lead, and age-old techniques which keep that sense of wonder alive. But in general, the life cycle of the vine can be broken down into several key stages during the year. 

Winter: The grapevine, like most summer fruit-bearing plants, lies dormant over winter, and sheds all its leaves. The roots source nutrients from the soil to keep the vine healthy and alive during the cold months. Growers may try to moderate the the temperature to give vines a higher chance of surviving during the cold months like “grounding up”.  Winter pruning occurs - the cutting of the previous year's canes (small vine shoots) to set the availability of shoots for the coming season.

Spring: Leaves and buds appear, and the vine comes to life! Small shoots will come off the main trunk and small flower buds will pop up along the vines – the buds eventually turn into grape bunches.

Summer:  Veraison occurs, this is where the young grapes turn from unripe and green to their true color! Flavors develop and harvest approaches.

Fall: grapes are harvested at various points (some as early as September or as late as the end of November). There are several methods to identify harvest time but most winemakers rely on a combination of taste, skill, awareness, and scientific testing to define exactly when the day (or even hour) for harvest should take place.