Wine Culture Magazine

Innovations and discoveries from the world of wine

Shade cloth for sun/heat mitigation at Daou Winery in Paso Robles. Supplied photo

Dressed to (prevent) kill

As we veer closer and closer to climate apocalypse, winegrowers around the world are turning to innovative technologies. Too much sun, heat and excessive cold temperatures for vines can be mitigated by specially engineered fabrics called geotextiles. Not at all like the burlap you might drape over your roses or shrubs, these are highly engineered cloths that fit snugly over vitis vinifera vines as they try to survive the elements.

Applying geotextiles in Quebec with a tractor. Photo courtesy of Texcel

Here’s the skinny.

• Geotextiles are mostly made from synthetic polymers like polyester, polypropylene or polyethylene and can be woven, knitted or non-woven (your workout gear is likely polypropylene).

• They are breathable, water impermeable and can either admit or deflect light.

• Using a geotextile reduces exposure to intense cold and wind in addition to minimizing sudden changes in temperature, increasing the survival rate of primary buds; it can be –25°C outside, and just –15°C under the thermal “blankets.”

• In vineyard areas with winter snow, geotextiles hit peak performance, maximizing the insulating capacity of snow that accumulates atop the fabric.

Vines covered in geotextiles to protect them from winter’s cold. Photo courtesy of Texcel

• In Quebec about 40 per cent of vineyards are covered with geotextiles in winter.

• The textiles are not opaque and allow solar radiation to promote vine growth, but but if growers prefer to delay bud break, they can deploy cloth with greater opacity.

• Not just for winter, woven or knitted shade cloth is used in hot and humid wine regions to limit UV exposure and sunburn, minimize dehydration, conserve water and prevent certain vine diseases that thrive in warm, humid conditions.

• Shaded grapes will have a slightly lower pH and higher acidity than unshaded grapes picked at the same time.

• A Paso Robles study showed black shade cloth showed lower canopy temperatures than white cloth, even at the same 40-per-cent light reduction for both colours.

• Geotextiles can be applied by hand or with a tractor, but correct, airtight installation is critical—and it can be expensive. In B.C., this can cost up to $5,000 an acre for the cloth, plus $5,000 more for the labour to install, remove and store it. In contrast, covering/uncovering vines with earth is about $1,800 per acre all in.

• Before geotextiles are applied, the vines must be pruned first, the timing of which has implications for bud break. Fall pruning is not always possible or preferred in many marginal wine regions, so earthing over would be a better strategy.

• Also keep in mind: The textiles need plenty of summertime storage with foolproof rodent protection.

Although Mexico is not well known for wine; it has a 500-year-long tradition of viticulture. Pictured here: the famous vineyards in the Ensenada and Valle de Guadalupe region of northwestern Mexico’s Baja. iStock / Getty Images Plus / Photo Beto photo

Boost your Mexican wine IQ

Mexico has a long and illustrious vinous history that goes back five centuries. One of the first acts of Hernan Cortes in 1521 was to order the planting of vines. Today, viticulture is widely established, with vines growing in a variety of habitats, from coastal regions to almost 2,300 metres above sea level. Limey, clay loams with good water holding capacity are in abundance and essential to vine survival.

• Vitis vinifera variety Listán Prieto was planted in Mexico in the early 1500s. (It became known as the Mission grape in California.)

• The oldest winery is Casa Madero in northern Mexico’s Valle de Parras, continually making wine since 1597.

• Experiencing a substantial recent growth spurt, there are now 21,259 acres of wine grape vineyards in Mexico, about 7,500 more than in B.C.

• There are three main wine-growing zones, but no geographical indications system as yet: North (Baja and Sonora); La Laguna in Coahuila and Durango; and the Centre (Zacatecas, Aguascalientes, Queretaro). Seventy per cent of all grapes are grown in Baja, which has more than 11,000 acres of vines.

• There are more than 400 licensed wineries in Mexico, more than 260 of them in Baja.

• An exciting array of more than 50 grapes are planted. Reds include Cabernet Sauvignon (20 per cent) then Merlot, Syrah, Nebbiolo, Tempranillo, Zinfandel, Cabernet Franc and Grenache. White wine grapes include Chardonnay (eight per cent), Chenin Blanc, Chasselas and Sauvignon Blanc.

• Another 100 more varieties are being planted experimentally.

• Wine production was at around 40 million litres in 2022.

• Mexican wine consumption is at 1.3 litres per person per annum (up significantly from 225 millilitres 20 years ago), and growing quickly, with 34 per cent of all wine consumed in Mexico domestic. Beer consumption, meanwhile, is 70 litres per person per year!

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