(Wineland) - The basic fact that oak barrels consist of staves and heads means that there could potentially be a great variation in the flavour contribution of the individual staves and barrel heads of different barrels; moreover this raises the issue that barrels are likely to differ in this respect. Although winemakers most probably know which flavours they require from barrels for specific wines, there is no absolute certainty that this will be achieved. ETS Laboratories in St Helena, California, offer an analytical and sensorial evaluation service to cellars with a view to limiting such uncertainties to a certain extent.