If you want to make good wine, you have to get your hands dirty — literally. The soil in which grapes grow has a tangible effect on the wine that ultimately ends up in the bottle. Below, we’re breaking down some of the most common winegrowing soils. Trust us: dirt matters!
Sandy soil comprises large earth particles, retains heat, and is loosely textured, providing an easy environment in which plants can take root. Because sand drains well (meaning it doesn’t hold water), vines in this type of soil are at risk for dehydration and must be watered often. The lack of residual moisture, though, comes with a real plus: it makes sandy soil virtually resistant to pest and disease such as phylloxera. In fact, it was sandy soil that helped some of California’s old-vine Zinfandel plants survive the phylloxera epidemic of the late 1800s!
Sandy soil isn’t inherently productive; to maximize cultivation and output, it’s often mixed with fertilizer or other organic materials. Warm-climate sandy soil produces lighter wines: lighter color, softer tannins, and less brightness. In cool climates, sandy soils produce highly fragrant wines.
Clay soil comprises miniscule earth particles, stays cooler, and retains water. Because it doesn’t drain well, clay soil can actually become over-moisturized and cause rot in vines. At the same time, though, the lack of drainage and the overall cooler nature of the clay causes grapes to ripen more slowly, producing fruit that’s naturally high in acidity and tannins.
Because clay is so heavy and compact, it takes longer for plants to establish themselves within it. Famous for producing some of the world’s boldest red and white wines (such as the highest-quality Spanish Tempranillo), clay soil provides the ideal atmosphere for Merlot and Chardonnay.
Silt soil comprises fine grains of sand and rock but retains both water and heat, making it incredibly fertile. (Need proof? The banks of the Nile are silt.) Despite the fine grains, silt is compact, increasing its ability to absorb nutrients and provide them to the vines. Because it erodes easily, it can sometimes be difficult for roots to take hold and for vines to thrive — but when they do, they bear fruit that produces smooth wines with a round mouthfeel and less acidity.
Loam soil comprises a 2-2-1 mix of sand, silt, and clay. Generally thought of as the ideal grape-growing soil, loam is ultra-fertile and retains pretty much the perfect amount of water due to its composition (clay holds a great deal while sand drains what needs to be drained). The addition of the silt means loam soil also absorbs nutrients — so combine that with its checks-and-balances water retention, and you’ve got one heck of a growing environment!
Plants take root easily in loam and can actually be over-vigorous, so this soil type produces the best grapes in regions with carefully maintained vineyards and strict pruning schedules. Examples of areas with this kind of soil? California’s famous Sonoma Valley and Napa Valley, just to name two.
Volcanic soil comprises basalt, ash, and other volcanic rock debris. This composition gives it a high mineral content (filled with nutrients such as magnesium, iron, and potassium), and the porous nature of the soil allows roots to take hold easily. Because volcanic soil holds little water, vines grown in it tend to be less vigorous and bear less fruit — but the fruit they do produce is considered high-quality.
Regions with volcanic soil include Italy, Napa Valley, and Chile, and wines made from fruit grown in this type of environment tend to exhibit heightened aromatics and a more distinct sense of terroir. Want to try one? Get your hands on a bottle of our newest Upswell!
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