Texas Terroir, Part One

13th Jun 2017 @ 10:16 by Ame

As a winemaker for 20 years in moderate-climate Chile, I was on my way last August to become the Director of Winemaking for Fall Creek Vineyards. The minute I got off the plane in Austin, I immediately thought Texas weather was just too hot for growing high quality wine grapes; it was something like 100ºF. But, my scientific proclivities prevented me from making a hasty decision, and I had to ask: is this a transitory heat wave? The answer was, “No, it has been, and it will be like this for several weeks.” Paradoxically, that answer seemed like ice water over the head as I grew concerned for my future winemaking career in Texas Hill Country and wondered what was allowing the Texas wine industry to prosper so.

I knew I needed to see the proof in the vineyards and the research data to explain the phenomena. I headed straight to the vineyards, expecting to find shriveled berries, raisined and sun-burned grapes, as well. I looked closely for these hot weather symptoms, signifying vines under duress. Instead, the vines were just fine with good color, healthy canopies, and turgid berries that were ripping nicely. I was positively surprised.

Heading to the cellar to further my exploration, I found that the wines from previous vintages (even hotter than 2013!) also did not show any sign of the effects of a hot year, such as unbalanced alcohol, diminished color on the red wines, and jammy flavors, to name a few. At this point, I was completely baffled. In my training and experience, in cooler climates, where the average minimum and maximum temperatures fluctuate between, let’s say, 64 and 92ºF in the hottest month of the summer, a 1-to-3 days heat wave of, say, over 100ºF would affect plants so much that growers would face a significant loss of production), and the wines would be unbalanced and underwhelming.

I was determined to find an explanation for what was happening in Texas vineyards that allowed the vitis vinifera vines to thrive and produce quality grapes despite the extreme heat of Texas summers. Given that the vineyards were not being managed in a different manner, I anticipated that the vines themselves were responsible for their own success. I asked Benjamin Lewin MW (former founder Editor of the life sciences journal, Cell) about the chance of some kind of adaptation of plants to heat, and he said that, in fact, that there is a set of genes, called “heat shock” genes, that are triggered precisely by continual exposure to heat. The ‘a-ha’ moment! Vines have evolved with an adaptation strategy to encourage survival under such extreme conditions. And if we think about it further, this makes sense if we consider that vines were originally cultivated and domesticated in an area between the Black Sea and Iran, where they experience even more torrid summers in some of these regions.

Apparently, it is a good thing that our summer temperatures go up in a slow but steady way, so plants can prepare themselves for what is to come. Then, in the middle of the July-August period they are fitted with their own sun screen, allowing those wonderful grapes to ripen, so we can make world class wines. More on this fascinating discovery in the next post.

Sergio Cuadra, Director of Winemaking