While preparing for the start of my advanced class (which started this past Sunday), I have been studying up on Viticulture and Winemaking. I want to devote this blog to the main factors that influence the quality level of wine produced in a specific site. And if you ask any quality winemaker about this subject, they will be the first to explain that there is a distinct and direct correlation between quality of wine and good grapes. Basically, if the fruit isn’t of good quality, you won’t be able to get a quality wine. Granted, winemakers can do many things to wines with their bag of tricks and ’spice racks’ that affect the flavors and overall style of a wine. But in the end of the day, if you don’t have quality grapes to start with, you’re gonna stuggle to make decent wine.
That being said, I would like to devote this blog to Viticulture, and as it really all begins in the vineyard.
When choosing a site to grow grapes, you must consider many things: Is the site near a large body of water? Where and what is your water source? What is the weather like? What is the soil structure like? Is the site on a slope or high in altitude? What grapes grow well at this site? I will start off this discussion with water.
A site located near a large body of water is considered ideal for several reasons. Water can store heat more effectively than land, so when the air temperature falls, it is able to release that heat. This is ideal for cooler regions where the evening get quite cool. Inversely, in summertime, warm air from the land rises in afternoons to be replaced by cooler air from the water. This cools the land and equalizes temperatures and the humidity levels. This is the effect that the Pacific Ocean has on the most important growing regions of California (Santa Barbara, Monterey, Napa, Sonoma, Mendocino). We also have the cooling effect of the fog rolling in from the ocean, as is the case in Monterey and Santa Barbara. This fog settles in and keeps the grapes cool all evening and well into the morning, as I have personally witnessed driving out of Santa Barbara on the 154 around 10am. Additionally, major ocean currents play a large role in keeping the climate cool on land masses. The Alaska Current keeps California cool, the Humboldt Current keeps Chile cool, the Benguela Current keeps South Africa cool. And the Gulf stream actually keeps Western Europe warm, as it brings the warm gulf waters up to Europe. Let’s also not leave out the effect that large rivers have on grape-growing. In the Mosel and Rheingau River valleys in Germany, the only possible way they can grow grapes (otherwise it’s too darn cold) is to plant vines right up alongside a moving river. Why? Well, since rivers move water, they prevent fog from settling in and hurting the vines. They also act to temper the region, much like the ocean tempers the land mass it is directly next to. The further you are from a large body of water, the more continental the climate will be (meaning you will have distinct seasons…cold winters and hot summers.) A clear example of this would be to compare the climate of California with say, Nebraska.
Not only is the overall cooling/warming effect important with water, but the actual water source to use to irrigate your vines is equally as important. You must have a water source to grow grapes. In some regions, like in Chile and Argentina, they have an ample supply of water from the Andes mountain range snow-melt. This gives them access to an abundance of water. They have so much, that they do what is called ‘flood irrigation,’ which basically means they flood their vineyards with water. Now, here in California we don’t have an abundance of water, and water is extremely expensive, regulated, and limited, so growers here are very judicious about how they irrigate their vines. Most quality growers ulitize a ‘drip-irrigation’ system where the amount of water that comes out and drips on the vines is timed and the quantity regulated. This allows growers to conserve water. Regions like Burgundy, Oregon, Bordeaux, Loire valley recieve enough natural rainfall so that they have an accessible water source. Australia faces similar issues as we do here in California, in that it is extremely dry.
The latitude, altitude, and slope of a site are also important to consider when growing grapes. Grapes grow best between 30 and 50 degrees latitude. When closer to the equator and the grapes don’t know when it’s summer and when it’s time to go dormant (winter). Further than 50 degrees is too far north and too darn cold for grapes, generally speaking. Altitude is important because in warmer climates, like Mendoza in Argentina, the only way grapes don’t bake to death in the near-desert conditions is because they are planted at altitudes of over 2000 meters. This creates a cooler condition of the site. The slope of a vineyard is also important in site selection. Slopes that face the sun are preferred over flat sites because the incoming solar radiation (insolation) is greater facing the sun. The effect becomes apparent at the end of the growing season when the sun’s heat is weaker. This warms the soils so that grapes can ripen easier. Slopes also allow for cool air to travel down the slope to allow the warmer air from above to replace it, keeping the site warmer into the evenings. This is referred to as the ‘thermal zone.’ The problem with this is that sites at the bottom of the slope can trap the cool air and develop frost pockets, which is not good. The best slopes face SE or SW. SE slopes catch the morning sun and warm up quicker, where SW slopes catch the afternoon sun and stay warmer longer. Wind must also be considered when growing grapes. When I visited the 2 different sites in Malibu last week, one site felt stifling hot because there was no breeze compared with the second site. So wind can be your friend in hotter climates, and it can be your enemy in cooler climates, as it cools the vines, reduces rates of growth and delays ripening. To counter the negative effects of wind, many sites plant windbreaks. Trees can be a natural way to plant a windbreak.
Soils, like choosing to grow grapes on a slope or not, can also warm or cool the vines. The best soils promote water drainage and heat retention such as dark soils or stone soils (Slate in the Mosel, Gravel in Bordeaux). Wetter soils are generally cooler as they retain more water, such as heavy clays. The most important and defining elements of a soil are its structure and texture. The best structure allows for free draining of water, nutrition in the soil, and good water holding capacities. In the end of the day, you need soils to provide sufficient nutrients and water for it to crop succesfully and to survive until the next growing season. Different soil types cause a vine to grow more or less vigorously. This affects the way that the vine ripens its crop, the crop level, sugar and acid levels and the quality produced from them. The best soils have an equal balance of sand, loam, clay, natural drainage, yet can still store moisture sufficiently to keep the vine supplied with water throughout the growing season and sufficient oxygen for roots to breathe and grow. Soils may reflect light and heat, or trap them releasing it into the evening. Soils should be sufficiently deep to allow for development of a solid root structure of the vine. Vines with extensive root systems can overcome quite extreme variations in water and nutrient supply.
Which grapes grow in which region is well defined in the traditional ‘old world regions’, but continues to be an exciting and ever-changing topic in the new world. We are not limited by tradition with winemaking in the new world, so we can experiment with grapes in different regions. For example, Paso Robles, Temecula, Malibu are still trying to find their indentity in which grapes grow best there. Of course, there is market demand that has a large part to do with that. When I was visiting Malibu last week, B-Allen, my viticulture friend was explaining that for the new vineyards he plants, people really want to grow Cabernet. He said that Sangiovese, Tempranillo, Zinfandel, Syrah, Grenache, even Merlot grow better in Southern California than Cabernet does, but if his clients want to grow Cabernet, than Cab is what he’ll give them. Not only does the market dictate what grapes to grow, but like B said, certain grapes grow better in certain regions that others. It’s too hot to grow Riesling, it’s almost too hot for Cabernet in Malibu. Inversely, it’s too cool for Cabernet in Willamette Valley Oregon, and Pinot Noir loves it there, as does Riesling (which are cooler-climate grape varieties).
I hope that you were able to gather a better understanding of what it takes to grow quality grapes. Grape-growing truly is agriculture at it’s most advanced levels. In both the winery and in the vineyard, to make quality wines, you must have money, patience, and a very detailed oriented nature. As B-Allen explained, he can’t just leave the vine, come back once a month, because if there are any problems that develop (like bees, birds, rot, or mildew), they move fast and before you know it your crop is devastated.
If you want to get even more detailed about grape growing, I would recommend purchasing the book, Viticulture by Stephen Skelton, MW. This is the book I have been studying myself and is the basis of most of the information I provided above. Furthermore, if you really want to learn about the world of wine, please reach out to me, lindsay@winesmarties.com, 619-955-8884
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