The Californian drought has been on the forefront of America’s mind. Business owners, particularly those in the agriculture sector, are thinking about how the drought will affect their business. Soil is second to climate in the importance of vine growth and health, so naturally soil is a key topic in wine country. Here at Beckmen Vineyards, we are lucky that our vineyard’s soil structure – clay topsoil with a limestone subsoil – performs very well in drought conditions. Think about all those times you’ve gone wine tasting and your host has mentioned the loam/granite/chalk soil and how it is important to the flavor and mouthfeel of the wine. It may seem unsavory to think about dirt when you’re wine tasting, but, soil matters. Vines prefer well-draining soil types; soils that retain water are ideal in drought conditions; limestone is the perfect combination.
Superior Water Retention
The Ballard Canyon AVA has a small outcropping of limestone, which Purisima Mountain Vineyard was built on. The limestone is made from fossilized marine life, created when the Santa Ynez Valley was part of the Pacific Ocean seabed. While vine roots cannot actually penetrate through this hard layer of rock, there are preexisting deep crevices in the limestone. Roots will search for water and other nutrients, channeling down into these crevices and creating deep root systems.
Calcium carbonate is the main element of limestone. When the hard limestone outcropping deteriorates, this calcium carbonate is then abundant in the topsoil, too. In our case, this topsoil is between 12 – 36 inches of clay. Soils rich in calcium are able to retain moisture very well in the dry seasons, and also have good drainage necessary for grapevines to thrive. Some of the best wines around the world are made from calcium-based soils with a high water retention rate: Champagne, Chablis, Loire, Rhône, and certain regions of Australia, New Zealand, and California.
Calcium is a necessary element for vine growth and vitality, both in the soil and in the plant itself. Vine roots can only absorb molecules, ions, and minerals, which are all needed to keep the vine alive. Roots growing in calcium rich soils have an easier time absorbing minerals, thus resulting in a healthier plant. When roots are happy and healthy, the vine can focus its energy on above ground growth in the canopy and fruit development.
Resistant to Disease Pressures
Calcium is also located in the grapes themselves; calcium in the grape skin is used as a defense mechanism for fungus and disease. If a vine has low amounts of calcium, however, the calcium is used inside the grape before being used to strengthen the grape skin. A calcium shortage then weakens the grape’s ability to protect itself against disease pressures. If you have a vine with healthy amounts of calcium, you are building a strong barrier against disease.
A Beckmen Example
When Tom and Steve Beckmen founded Purisima Mountain Vineyard, they knew the calcium rich soils would help distinguish their wines. A prime example of how the soil helps to create outstanding wines is our 2013 Purisima Mountain Vineyard Syrah Viognier. This wine has a noticeable minerality, which is easiest to pick-up on the palate. The savory, saline aspect, which entices you to take another sip as soon as you’ve swallowed the wine, is due to the minerality. Grapes grown on calcium rich soils also tend to have a higher acidity, which creates that long, mouthwatering finish in the 2013 PMV Syrah Viognier. If you can’t notice these flavors or characteristics, don’t worry. Just know that the soil impacts the way wine tastes.
The Beckmens saw the potential in the soil of the unplanted 365 acre ranch they purchased in 1996, which they would then turn into one of California’s premier biodynamic vineyards. The first step in creating world class wines is starting with the highest quality fruit possible. No matter how good your winemaking skills are, you can’t make good wine from bad grapes; our limestone soil ensures that our grapes are one step ahead of the bunch.
If you would like to learn how soil affects the outcome of wine on a deeper scientific level, I suggest reading these two articles on Calcium in Viticulture Part 1 and Part 2. I used these articles to help break down the basics of limestone soils.