Natural Factors in the Vineyard – What Makes A Wine

Harry Lambourne
6th June 2023

If you love your wine then, you must always remember that vineyards are where the magic happens. These mini-ecosystems and micro-climates combine to produce specific sets of conditions that allow grapes to thrive in unique and exciting ways. The specific set of natural factors in the vineyard has a clear effect on the wine which you drink.

There’s a reason your favourite grape variety doesn’t quite hit the spot, like it does when it is paired with your favourite region. There are specific natural factors in the vineyard which cause the wines to exhibit specific characteristics.

We’re going to take a look at the crucial elements which a vine needs. Namely, heat, sunlight and water. These are the primary natural factors in the vineyard. From here, we will extrapolate how various topographical factors can mitigate or exacerbate those natural factors in the vineyard. This is closely linked to the idea of terroir.

Ever wondered why Riesling from the Mosel region in Germany is planted on steep southern facing slopes along the River Mosel? Maybe you want to know why the presence of different water sources is so crucial to Bordeaux?

Bordeaux River in Autumn Evening
Bordeaux Vineyards – The Best Can ‘See The Water’

Well, by the end of this you’ll know why. Beyond that, you’ll be able to look more into your favourite region and see what the winemakers do to produce that great grape juice which you love, just the way you like it.

Natural Factors in the Vineyard – Heat

Heat is one of the crucial natural factors in the vineyard. Vines need heat. They won’t grow properly if temperatures are below 10 degrees celsius. This is why they’re dormant in winter and only begin their growth in spring.

Importantly, grapes also require different levels of heat. Riesling can thrive in the cool climate of Germany, but there’s a reason we don’t associate Cabernet Sauvignon with Germany. It requires longer periods of warmer weather. Cabernet Sauvignon simply couldn’t achieve the full ripeness it requires in the vast majority of the cooler German climate. You’d get an overly astringent final product with harsh bitter tannins.

Utilising heat is crucial for winemakers. They need to manipulate natural factors in the vineyard. If heat is in short supply then they need to maximise their exposure to it. If the vineyards are especially hot, then they need to take steps to mitigate its influence. So, let’s look at how factors in the vineyard can help winemakers control the levels of heat.

Latitude is crucial when discussing heat as one of the key natural factors in the vineyard. Admittedly, this is a factor that winemakers can’t do much about, beyond planting vines somewhere else altogether. Yet, they’d be taking it into consideration when choosing what varieties to plant.

Almost all vineyards line between a latitude of 30 and 50 degrees, although exceptions apply. This includes areas of northern Argentina like Cafayate. This range is considered the most optimum range for planting vines. It generally ensures that sufficient heat is generated for the vines and it also allows for ample sunlight exposure.

Cafayate Vineyards - Natural Factors in the Vineyard
Cafayate Vineyards – Cooled By Altitude

This brings us onto our second point when considering heat as one of the natural factors in the vineyard – altitude. Cafayate, (pictured above), falls outside the usual latitude range, so as you can imagine it would be very hot. This would usually mean subtle and delicate aromatic grape varieties would not be suited to this hot environment. They’d become overripe and lose their acidity.

However, winemakers adjust and Cafayate is home to some of the highest vineyards in the world, with some located at over 3000 metres above sea level. This is just shy of the height of Mount Etna in Sicily, which stands at 3329 metres. The altitude helps to cool the vineyards. Higher altitude generally means less heat. This allows them to produce stunningly fresh and aromatic Torrontés wines in a region that should be far too hot!

If you’ve not tried it yet, we’d strongly recommend picking up a Torrontés from the Cafayate region of Argentina. The very fact that this region has seen the Torrontés grape variety prioritised over Malbec should speak to their belief in its quality.

They truly make some of the best expressions of this grape variety in the world. They retain their aromatic qualities and their freshness but they also have a real concentration of flavour thanks to the exposure to the sun.

Expect a reasonable punch of acidity and a medium to light body. Then, a wonderful mix of floral, citrus and stone fruit flavours display themselves in a truly bewitching way. Common tasting notes include roses, orange blossom, geranium, lemon zest, bergamot, grapefruit, peach and apricot. Don’t miss out and get shopping for some of Cafayate’s finest today!

Now, we move to the ocean currents. An undeniably key aspect of heat as one of the natural factors in the vineyard. These mammoth meteorological events can have a spectacular effect on vineyards. Hot areas like Chile and South Africa are cooled by the Humboldt and Benguela Currents respectively. South Africa and Chile are both deeply hot comparative to other grape growing regions but these cooling currents help contribute to wonderfully fresh and vibrant País in Chile and Chenin Blanc in South Africa.

On the other side of this, areas like North-West France and Southern England benefit from the warming Gulf Stream, (although it often doesn’t feel like it). A combination of growing temperatures and the Gulf Stream have helped improve English vineyards no end. Wonderfully complex and elegant sparkling wine can be found across Southern England as it reaches temperatures comparable to regions such as Champagne.

The natural factors in English vineyards have changed a lot in recent history. This point requires attention. The natural factors in the vineyard that affect a region today, may not be the most prominent natural factors in the vineyard in the future.

Camel Valley Vineyards
Camel Valley, Cornwall – Vines Warmed By The Gulf Stream

Even the very soil that vines are planted in can affect the heat. High stone and rock content soils traps and reflects heat. This can be crucial for cooler areas. High water content soil has the opposite effect.

To take it back to Bordeaux and the fabled region of Graves, unsurprisingly it has soil with high gravel content. This helps to ensure the the full ripening of Cabernet Sauvignon grapes, in what can be a cool region. The area of Gimblett Gravels in Hawke’s Bay in New Zealand is another example of this. Despite lower temperatures, the gravel soils have allowed for world class Cabernet Sauvignon to flourish.

One last consideration involving natural factors in the vineyard is the aspect of the slopes, which we touched upon in reference to Mosel. This refers to the direction the slopes are facing. Generally speaking, winemakers looking to optimise sun exposure and the related heat will plant slopes facing south in the northern hemisphere and facing north in the southern hemisphere.

The steepness of the slopes is also key. Steeper slopes equals more sun. The Northern portion of the Rhône Valley is a region famed for its perilously steep slopes. In the northern regions of appellations such as Côte-Rôtie, hand-built stone walls and set into ancient, loose granite slate soil. These walls help keep these vines from tumbling down the hill. Perhaps, more importantly though they provide a great exposure. They’re steep with a southerly aspect. This very factor is one of the primary reasons that these are some of the most northernly places that Syrah grapes can fully ripen. You get these lean, peppery styles of Syrah that are so coveted and fetch such high price tags.

To bring it back to Mosel, they have a combination of natural factors in the vineyard which combines the soil, aspect and slopes. Mosel has slate stone soils, southerly aspect and steep slopes. This is to maximise the amount of heat that the vines get, as Mosel is a cool region. This allows the grapes to fully ripen, while instilling a clear minerality.

Natural Factors in the Vineyard – Sunlight

Photosynthesis is not just a word that you may have forgotten from school, it is also the engine of any plant. It is the name given to the process where plants use sunlight, water and carbon dioxide to create oxygen and energy. If this process doesn’t occur, then they die. Without sunlight it won’t occur.

This is what makes sunlight one of the key natural factors in the vineyard. Increased levels of sunlight promote growth and healthy vines. So, it’s easy to see why winemakers would want to increase it. Let’s look at the factors which affect this.

We’ll begin with latitude again. Simply put, the further away from the equator that the vineyards are then the longer that the day length is during summer. This is why so many Scandinavian countries can boast the ‘midnight sun‘.

These opportunities for long ripening periods are crucial. The long, cooler growing season in Germany is why Riesling has had such success there. Beyond that, the German Spätburgunder, (Pinot Noir to you and me). A great example is the German region of Ahr. This falls outside standard latitude, as it’s above 50 degrees. However, the sunlight helps ensure that grapes still ripen.

Large bodies of water, such as seas and lakes, can also increase the sunlight exposure. The River Mosel does this for example. The sunlight reflects from the bodies of water increasing exposure.

Rivers and lake are staples across the whole wine-making world. The Mosel, the Loire, the Rhône and the Rhine are just a few key examples and that’s only a small portion of France and Germany!

Steep Vineyards in Mosel
The River Mosel – A Great Source of Sun

Aspect is once again an important point and the logic remains unchanged from the point surrounding heat. Point vineyards towards the equator to increase the level of sunlight exposure and promote healthy ripening. Our previous reference to the Mosel and Rhône regions remain key examples of how aspect promotes growth.

Natural Factors in the Vineyard – Water

Water is also crucial to the process of photosynthesis and one of the key natural factors in the vineyard. Water is drawn up through the roots and into the leaves. Temperature is related to the amount of water needed. Water evaporates from the plant at a higher rate in hotter temperatures meaning more water is required. This is why irrigation is also an important factor of how water affects vineyards.

Of course, rainfall is the primary source of water in any vineyard. This can be both a blessing and a curse. Not enough water leads to drought and underdeveloped grapes. However, too much water, particularly at the time of harvest will cause the grapes to swell with water which will reduce the flavour.

Yet, rainfall can be scarce or unreliable. So, winemakers opt for different methods of irrigation. Irrigation is how winemakers ensure that grapes receive ample amounts of wine without relying on rainfall

Drip irrigation is an advanced method which ensures an optimum amount of water to each vine, but it’s expensive. High tech regions such as New Zealand often opt for this method of irrigation.

The high costs are why sprinklers are widely used. They’re effective but inefficient and can cause a lot of water waste. Sprinkler systems can be found through the Central Valley in California. They provide cheap irrigation to hot, dry areas which are famed for producing high-volume inexpensive brands of wine. Blossom Hill White Zinfandel anyone?

None are as cheap and inefficient as flood irrigation though. However, this is only possible in gently sloping vineyards where large quantities of water are available. Flood irrigation would be completely untenable in most regions. However, Mendoza is famous for it. Snow on the Andes Mountains melts. This snow melt rolls down the mountain side and into the vineyard through strategically dug paths. It then provides the vines with the vital water that it requires.

Vineyard in Mendoza, Argentina
Mendoza and the Andes – Famous for Flood Irrigation

That’s a quick whip round some of the main natural factors in the vineyard that affect winemakers decisions. Natural factors in the vineyard help mould the grapes you know into the wines that you love. Now, you can look into the regions that you always look for in greater detail. Try and see if you can determine which natural factors in the vineyard are helping to produce wine just the way you like it!

Why not pick up a wonderful organic Riesling from Mosel? Now that you know exactly what natural factors in the vineyard go into making this grape work in the stunning Mosel region.

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