As part of our ongoing quest for excellence at Montalto we have a trial program in the winery whereby each vintage we introduce new and innovative vinification methods together with exploring new processing aids, including oak, to help us discover the full potential of our vineyard sites and style objectives.
Regarding oak barrels, to date, French oak has been my choice for the Montalto wines. American oak is typically more intensely flavored than French oak with more sweet and vanillin overtones and in my opinion isn’t well suited to the traditional Burgundian varieties of Chardonnay and Pinot Noir.
In 2017 we decided to explore the less travelled path and venture into unchartered territory purchasing a small number of Acacia barrels with a view to seeing how they might work with our grapes.
A barrel’s attributes will be heavily influenced by the growing and climatic conditions of the tree and its origins. Winemakers usually select oak from particular forests with certain grain tightness to match qualities with those of their grapes and the desired wine style. Together with the forest, seasoning of the oak is another determinate of quality (the process of air-drying the milled timber to leech out green and bitter characters). Oak that is seasoned longer tends to show more mellow characteristics compared to a short seasoning period where sappy and aggressive tannins may prevail. Coopering techniques will further influence the flavour and structure profile in a wine.
Oak imparts both structure and flavour in the wines. The structure comes from the tannins that are released from the oak into the wine together with an array of aromas and flavours, and the subsequent toasting levels imposed on the oak by the cooper.
Some coopers choose to bend staves using a combination of fire and water, whilst others use just steam with differing outcomes on flavour and tannin structure.
The term ‘toast’, or ‘toasting’, refers to the process of a cooper placing a barrel over a contained exposed flame to toast the internal lining for a specified time period resulting in flavour and tannin changes caused by the interaction of heat and fire with the oak. A ‘low-toast’ barrel usually exhibits a rawer wood character and more dusty and astringent tannins compared to ‘medium toast’ displaying more coffee, chocolate and hazelnut flavours with softer tannins. ‘Heavy toast’ barrels express more smoky/charry characters including roasted coffee with a lower tannin profile that is more drying on the palate.
Being a porous substance, oak also permits exchange of oxygen in very small quantities allowing certain chemical reactions to occur during the maturation phase. The result is a softening of tannin structure, stabilisation of colour and flavour integration and development.
As a barrel ages, it loses its potency, much like a tea bag will if you use it over and over again – eventually all the benefits will be leeched out. The vessel will still however offer value for maturing wines where lesser oak influence is desired.
Acacia has a unique flavour profile and the porosity and tannin profile is very different to French oak, With our Acacia trial, the jury is still out, but early signs show a smoky and sappy quality, which may sound unappealing now, but it is amazing how a miniscule portion of a less desirable attribute can add incredible dimension and complexity when combined as part of a larger blend.