“How does the percentage of new oak affect wine?” Frank W
Before the industrial revolution and the production stainless steel, concrete, fibreglass and plastic, we didn’t have many alternatives for the storage of wine. Ceramic amphora were used early on and then eventually barrels. Glass bottles strong enough to hold wine didn’t start being produced until the early 1700’s.
Today we still mature it in a variety of vessels including wooden barrels, made not just from oak, but, chestnut and acacia (wattle) too.
In reality, this is a question that winemakers always find amusing. It overcomplicates what is in reality very simple. Taste the wine when you making it, if it looks like it has too much oak, then move it into another neutral vessel, old barrel or otherwise. For the consumer, taste it, is the oak balanced, excellent, if not wait, taste it later just to make sure, sometimes oak settles in young wines with air and a year or two in bottle. In Europe they rarely talk of these stats, focusing more on whether or not the wine has harmony, balance, and, is a good representation of the year and vineyard.
Most of the images in this post courtesy of François Frères. Many of the finest Burgundy producers use their barrels.
Why mature wine in a barrel?
We mature wine in barrels for two main reasons:
- To support the process of élévage, developing the wine from a raw product to a more refined wine through the gradual introduction of oxygen and clarification through natural sedimentation.
- To impart oak aroma, flavour, and, tannins, layering in more complexity and impacting the mouthfeel.
How does the percentage of new oak affect the wine?
Don’t get hung up the numbers, the numbers can lie! Taste it.
The larger the format oak used, the lower the impact of new oak. A new puncheon (500L) has 25% the impact of a new barriques (225L) due to its lower surface area to volume ration. The smallest barrel has the best name at around 40L it’s called the ‘Firkin’.
It’s much more important to taste the wine, assessing it for balance and harmony.
The Cooper has an influence
Coopers (barrel makers) have changed the way they make new barrels. They have modified seasoning (the amount of time the oak is aged outside prior to being made into a barrel). The temperature, humidity and duration of toasting, the process where barrels are literally toasted over a fire post, charring the inside, has changed. The forest, tree selection and blending of different wood sources has changed.
30 years ago if you bought a new barrel in Australia you’d be sold on bang for buck, maxising the amount of aroma, flavour, and, tannin the barrel could give. Now winemakers are increasingly looking for restraint and elegance from any oak contribution. Basically 20% new oak 30 years ago was equivalent to much higher levels of new oak today!
When we chose new oak for the Wine Decoded ‘Bathtub’ Shiraz we went to the barrel importers winery and tried all of the different barrel types with Chardonnay in them and made an assessment of which we throught would best compliment our fruit source.
It’s not just the new oak
Beyond new oak, we know that oak continues to impart character to a wine for a number of years. A wine with 5% new oak and 95% 1 year old oak could have a great amount of oak character in it than a wine with 20% new oak and 80% old oak.
It all comes back to taste! It’s simple to hard to work anything out from the detail of numbers.
The source of the oak
The two best known sources of oak are French and American, more recently we’ve seen Russian, Hungarian, and, Slovakian oak in the mix in Australia. French oak tends to have more restrained aromas and flavours with finer tannins. American oak, an entirely different species of oak, often has quite overt vanilla and coconut aromas and flavours and depending on the cooperages courser tannins. One of the main difference with American oak has historically been the milling of the oak. American oak was traditionally, less so today, quarter cut, cutting through and across the grain. You get more usable timber, the quality suffers. French oak is normally split along the grain and has a tighter grain. For whatever reason, this has produced finer tannins.
Seasoning time & method
Before oak is milled into staves it exists as planks that need to be seasoned, you can’t make a barrel out of green wood. Seasoning dries the wood and hardens it, in addition to changing the flavours, aromas, and, tannins that will be imparted into the wine. There are two methods for seasoning oak:
- It can be stacked outside exposed to the elements, to wait for the moisture content to drop to appropriate levels, and, remove green flavours, minimum 18 months. Additional time can be added to ‘soften’ flavours, aromas, and, tannins. When you order a barrel one of the key specification outlined by the cooperage is the minimum time for seasoning. Oak can be seasoned for up to 3 years, rarely beyond.
- Alternatively, cheap barrels are made by kiln drying the wood, placing it in a massive oven and heating at an appropriate temperature until the desired moisture level is reached.
Time in oak
Just think about this like making a cup of tea. The longer you steep it the stronger it gets. Making our 2016 Wine Decoded ‘Bathtub Shiraz’ we had 1 x new barrel, 1 x 1 year old barrel, 2 x old barrels, all 228L. About a year in we shifted this to 2 x old hogsheads (300L) and 1 x old barrel and a stainless steel keg for the balance. Why? Our aim was to simply layer in a complexing character, not show overt oak. After around 12 months the wine had enough oak character and tannin, had seen a gentle period of éléevage, so, we wanted to slow the éléevage and avoid infusing in more oak into the wine.
I could sit down and try and work out the time weight percentage of new oak, life’s too short. Let’s just say I think the wine tastes pretty bloody good. I may be a touch biased!
In areas like Barolo, Barbaresco, and, Montalcino, it is common for winemakers who use small oak with a portion of new oak to transfer the wine into large Botti 1,200-5,000L in size for the same reasons.
Shape & Size Trends
There is an infinite array of barrel shapes and sizes, in Australia the two most commonly used: Barriques of 225-228L in volume, mostly Eastern States, and, Hogsheads 300L in volume, mostly South Australia.
In the last decade, we’ve seen much more experimentation with on this front with Puncheons of 500L and larger format Foudre (French) or Botti (Italian) being used.
From a wine style perspective the larger the vessel the lower the surface area to volume ratio, this reduces evaporation, oxygen ingress, slows the maturation, and, reduces the influence of new oak compared to barriques.
From a practical perspective, it reduces the labour needed to top barrels up as the ‘Angel’s share’ is lost and to rack, clean, & fill barrels.
Shape and size impacts lees contact, particularly pertinent for white wine. Benjamin Leroux is using shorter flatter barrels that allow greater lees surface area helping create a more ‘reductive’ environment and protect the wine from oxidation.