Friday, 10 July 2015

Friday Fungus: Terroir - or how fungi make your wine taste different

The idea of 'terroir' is well-known to wine buffs and is most commonly described as:

In a larger context, wine tasters try to define terroir as the specificity of place, which has come to include not only the soil in a region, but also the climate, the weather, the aspect of the vineyards and anything else that can possibly differentiate one piece of land from another.

The same grape grown in a different place will produce similar but distinct wine. And the wine buffs will talk about soil, climate, aspect and even the phases of the moon in trying to explain what this all means. Funnily enough they never mention mushrooms let alone fungi. Well they should:

Professor White offers a scientific, if unromantic explanation of terroir: wine character can be determined by the rate of water and nutrient uptake by the vine, and different types of soils will affect this rate — with microorganisms playing an important role in this process.

He describes how the mycorrhizal fungi in the soil form a symbiotic relationship with the vine’s roots. “The mycelium of the fungus grows within the root itself,” he says. “And some of the hyphae grow out into the surrounding soil, extending the root surface available and enhancing the uptake of water and nutrients such as phosphorus.”

The degree to which these fungi are around plus the different varieties will affect the rate of water and nutrient intake - ergo changing the flavour of the wine. And there's more because those other (and rather important to making alcohol) fungi, yeasts will vary from location to location:

“The wild yeasts that come in to the winery from the vineyard with the grapes can influence a wine’s character, particularly at the start of a spontaneous ferment,” says Paul Chambers, research manager in biosciences at the Australian Wine Research Institute in Adelaide. “And there’s mounting evidence that the complexity of microflora of each vineyard varies from region to region.”

Terroir is a romantic notion filled with the idea of a place's history, its uniqueness - the concept is part of wine's mystique. Yet the reality is that microbial variations and the different fungi knocking around the patch are the reasons for that difference rather than just soil, climate or aspect (and let's be clear that the phases of the moon stuff is nonsense).

Another way in which fungi make our lives (and the wine) wonderful!


1 comment:

asquith said...