To the ancients, the idea that plants are formed from the soil would have seemed self-evident. The communion between the roots and the earth suggests that the composition of plants, and by extension the fruit they produce, is determined largely by the composition of the soil. Modern science, however, paints a rather different picture. The fact that you can produce perfect-looking plants and fruit using hydroponics, where the plant is supplied with just water, light and a solution of 16 trace elements, demonstrates that the intuitive notion that the soil makes the plant, is quite mistaken.
Plants use light, water, air and trace elements to synthesize everything they need. Think of them as remarkable chemical factories, taking very basic raw ingredients, and synthesizing complexity from them. Moving to viticulture, specifically, grapes – the starting place for wine production – are made entirely through the process of photosynthesis and the subsequent biochemistry that builds and modifies the building blocks of sugars into complex biology. The soil? It’s merely supplying water and dissolved mineral ions. These nutrient minerals are derived from the vineyard geology, but they are only needed in only tiny quantities by the vine, and have little if any aroma or taste.
But let’s leave scientific fundamentalism aside for a second, and consider the experience of winegrowers worldwide, over many centuries. This experience testifies that soils are actually vital for wine. You can take a trip to a vineyard region such as Burgundy, and discover that when vineyard boundaries are coupled with changes in underlying soil structure, two neighbouring vineyards can differ significantly in the quality of wine produced.
That underlying geology impacts wine so strongly is undoubted. The cost differential between a Grand Cru Burgundy and a lowly generic Bourgogne, or even a respectable village level wine, is such that there is a significant financial incentive for a winegrower to do all they can to improve the quality of their wine. But even where great care is taken in the vineyard, yields are dropped, and the highest level of winemaking is practiced, there seems to be a quality ceiling that is imposed by the vineyard.
So we have a dilemma to solve: how is it that soils seem to be so important for wine quality, when science indicates that they are only playing a limited role in influencing the flavour of grapes? This is one of the questions that intrigues me most in the world of wine, and I’m going to try to attempt to answer it.