Sorry all for making such a long and boring post! But there are a few questions I'd like to know more about?
Admiral wrote:Is that correct? Is the vanilla you speak of actually inherent in the american oak? I thought the vanilla associated with american oak was more because the oak had previously been used to mature bourbon, and it is from the bourbon maturation that the american oak subsequently imparts vanilla notes to the second fill.
It is indeed correct! The technical term for vanilla aromas is "vanillin", and it's the wood that imprints the bourbon with vanilla aroma - not the other way around. The american oak (Freedom Oak - sorry, couldn't resist hehe) has a considerable stronger vanilla character than its (in particular) french counterpart. That is also what makes it so suitable for scottish single malt purpose. The french oak is too dry but I suppose the Laphoaig Forty (uses Limousine oak) has matured for so long that the limited sweetness available in the wood will be extracted and put to good use with the mellow whisky. The "dry" character of european oak is well illustrated by the fact that the fashion of "finishes" are just that - finishes! The whisky probably wouldn't be very enjoyable if matured in fresh european oak barrels only because of a lack of sweetness.
So what about the ex sherry butts. Now, that's the point where I'm getting confused myself! I read somewhere that contrary to popular belief it isn't the sherry residuals but the wood that leaves the imprint on "sherry whisky". Fine, but does that mean there's a marked difference in the quality between the french and the spanish oak? And if the "bourbon example" is anything to go by - wouldn't it be logical to asume that the sherry wine as does bourbon - draws out the strongest flavours in the wood. So, when you use the solera system (barrels stuck on top of eachother for years - constantly refilled with parts of new wine) wouldn't it be logical to say that there isn't any flavour left worth mentioning because when the cask isn't good enough for sherry it's then sold off to the whisky producers. Hm, despite what I've been reading I'm inclined to believe that it must be "sherry saturated" wood that makes a sherry whisky?
Secondly, there are two ways of making an oak cask/barrel and it might even have an effect on how we judge the colour of our whisky! In order to bend the oak staves into the barrel form you can either steam the wood or use charring. The latter is the prefered method, but also the most expencive way of doing it. It must nessecarily have an effect on the colour of the bourbon - but does it affect the whisky? I don't know, but I wonder if whiskies like the Ardbeg 10's lovely pale white wine colour is a direct result of steamed barrels? Or does the bourbon absorb all of the colour?
Also, I thought the spanish winemakers traditionally used european oak, but - just like the scotch industry - they too are now taking advantage of the fact that there is a steady supply of ex-bourbon casks coming out of the USA for considerably cheaper prices.
Spanish winemakers have made good use of both, but american oak has in many of the largest regions (Rioja for example) been dominant. I belive it's about to change mainly because of two factors. Firstly, the market is increasingly asking for young and fruity wines with little maturation. Secondly, the premium market niche for matured quality wines is getting more focused on the quality of oak flavour - that it's better integrated and balanced in the wine instead of being an overpowering flavour - like many if not most spanish wines used to be.