To oak or not to oak, that’s just one of the questions. Andrew Polmear goes where we can’t to find the answers 

Almost everything about wine tasting is supposition, especially what I think of as the ‘Great Debate’- what makes a wine taste as it does? How much is it the result of unalterable things – the ‘terroir’ – and how much due to the intervention of the winemaker?

It’s rare that one has a chance to put anything to a real test. It would need a controlled trial, and that’s not the sort of thing winemakers do. Except for Luc Schweitzer, the owner of Château Bourdieu, in Blaye, Côtes de Bordeaux, an appellation on the right bank of the Gironde river from the châteaux of St Julien in the Upper Médoc, but on different soil and without the cachet that makes those Médoc wines so expensive.

In 2019 Luc made two wines that won prizes at the Decanter World Wine Awards. What’s interesting is that the two wines were made with virtually the same mix of grapes (about 88 % Merlot, the rest being Cabernet Sauvignon and Malbec or Cabernet Franc) from the same vineyards.

The one that scored 97 out of 100 is called Château Bourdieu. It was fermented in stainless steel vats for four weeks, then aged in fresh steel vats before bottling. Luc’s aim was to preserve the original fruit flavours. 

The one that scored a mere 95 points (still a fantastic score for a Blaye wine) is called Château Bourdieu No. 1. It was made in the same way except that it spent six months aging in oak barrels. Luc’s aim was to allow the development of greater aromatic intensity. So, how do they differ?

The judges tasted blind. They only knew that the wines were from Bordeaux. They found the unoaked version  “Flamboyant and deep with ample, lush and fresh forest fruits, bramble and cassis, with cascading sweet spice swiftly following. A super brooding wine which will shine brighter with time”.

The oaked version was praised for its “pristine definition of damson, cherry and plum, with understated vanilla oak. Deep and long, the palate reveals a cascade of fleshy black fruits over ripe, fine-grained tannins and fruit-bonded acidity. Lovely stuff”

So they spotted the difference, even if it’s a bit hidden in their flowery prose. Both were rich in fruit (which ones doesn’t really matter) but the unoaked wine was lush and fresh, while in No.1 they could taste the vanilla of the oak and they detected tannins, that weren’t present in the unoaked wine.

Tasting the two side by side, I would go further. The unoaked version is all about the richness of its fruit. The oaked No.1 goes into a different realm where the fruit is transformed into something deeper and more complex. It’s the slightly smoky, rich velvet of a classic right bank Bordeaux. So now we know that it’s the oak that gives it that. How does it do it? Mainly by being porous. Tiny amounts of water leak out and tiny amounts of air leak in. It’s the oxygen that allows those extra flavours to develop.

While I prefer the No.1, what’s amazing is that both bottles sell for under £15. I bought them online from the wine merchant Exel.