Maryanne Egan is a winemaker at Wantima Estate in the Yarra Valley and one of the presenters of the SBS series The Wine-lover's Guide to Australia . It depends on what style of wine you're making. Aromatic style such as riesling or sauvignon blanc very rarely see any time in the wood. They are made, fermented, kept in stainless steel and bottled fairly quickly, and that's another advantage of an unwooded chardonnay. It's treated as a wine that doesn't need a long maturation period in wood, so it just is into stainless steel for fermentation, cleaned up, left in stainless steel tanks and bottled reasonably quickly after it's been made.
All red wine is aged in wood because it does require a longer ageing period.
The wood lets a little bit of oxygen through the staves of the barrel so inbetween, through the porosity of the wood if you like and that gives the wine a gentle ageing while it's in there. It's important to soften off the wine and for it to lose some of its very basic primary aromas. Some styles of white wine benefit enormously from spending time in oak and mainly chardonnay. Yes they are. There have been some chestnut barrels but they're used very very rarely.