Thursday, December 15, 2011

Tong and Minerality

So there's this quarterly magazine for serious geeks called Tong.  It's published in Belgium and to get it in America it costs like $150.  It's not glossy, there are no ads, most if not all of the authors are either MWs or are really famous...lots of words.  Each issue is grouped around a particular theme, like Bordeaux, Chardonnay, or Oak.  Pretty geeky.  I love it, but I wish someone I knew got it and would loan it to me because it's just really really expensive.

Anyway, that's neither here nor there.  Tong just came out with a book that they call a general text on Wine.  It's called, "Wine."  Being a total snob and shocked at the value of the dollar against the Euro, I wasn't going to order it until they emailed this excerpt that dovetailed completely with what I am studying in my WSET classes, namely soil nutrients and anaerobic fermentation.  It's fairly provocative for an intro text:

(An excerpt from our book "WINE", p66) The word “minerality” often crops up in tasting notes, especially when describing white wine. This often implies that there should be a direct link between the minerality of soil and wine. The generally accepted notion assumes the higher the mineral content of the soil, the more intense the mineral flavour in wine. This is nonsense. Most minerals do not have a flavour and at most a slightly salty taste. Their presence in wine is minute and they go organoleptically unnoticed amongst fruit flavour, tannin, acidity and alcohol. Scientific trials have shown that there is no direct relationship between soil composition and the flavour of wine. Minerals are essential plant nutrients necessary for growth, photosynthesis, etc. The most important minerals are nitrogen, phosphorus, potassium, calcium, magnesium, sulphur and iron. A surplus of minerals in the soil causes vigorous growth of the vine and excessive yields that result in a thin and flat wine. Therefore the theory that more soil minerals make a more complex wine is obsolete. “Mineralic” wines are mostly grown on stony soils which tend to be poor because they contain little nutrient-rich humus. Vines on stony soils have to fight for survival and the grapes, just like the vines, accumulate few minerals, especially very little nitrogen. This can cause problems during fermentation as yeasts require nitrogen to convert sugar into alcohol. If there is insufficient nitrogen in the grapes, yeasts will split sulphur-containing amino acids to access nitrogen. This can cause the formation of volatile sulphur compounds which can come across as “mineralic” in wine. This does not point to a sulphur-rich soil but explains the indirect link between soil and wine flavour.


I can buy this from the point of simplified chemistry.  All that stuff about nitrogen starvation during fermentation is well covered in several of my textbooks.  But it does beg a huge question, which is "what the hell good is site selection?"  Why is wine from one block always a little tighter than wine from the one next to it?  A little richer, a little leaner, a little more flinty?  Why can some critics make astonishingly accurate blind identifications of soil types? 

Perhaps it is because primary fermentation is only part of the story of wine.  We are talking about hundreds of different chemical reactions and thousands of esters, volitile compounds, and byproducts.  I suspect there is more to this story.

1 comment:

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