At a recent wine tasting in Serbia, they said the barrels are burned on the inside and that provides protection against rot (as well as adding flavours). They also said they can only use the barrels for 2 years before the wine has extracted all the compounds it needs from the wood, at which point they sell them to whisky distillers.
the_drew t1_iujfcf4 wrote
Reply to Eli5: how is it possible that a wooden barrel, which is used for aging alcohol, does not rot away. by OrneryGringo
At a recent wine tasting in Serbia, they said the barrels are burned on the inside and that provides protection against rot (as well as adding flavours). They also said they can only use the barrels for 2 years before the wine has extracted all the compounds it needs from the wood, at which point they sell them to whisky distillers.