There is something poetic about oak barrels. They give wine finesse and complexity, adding extra notes of spice, wood and vanilla to the fruit aromas and flavours. The barrel rooms are also the calmest places in the cellar at Jordan. Away from the din of the pumps, crusher and press (which all are really, really noisy during the day), the cellar room is an oasis.
The oak barrel treatment that wine-makers give to wine is necessarily careful and deliberate. Every year Jordan places orders for barrels from several cooperages in France and the US. They look at the sales of their oaked wines to determine how much to make for the next year, how many new barrels they will need, and how much wine from a tank to put into the barrels. As Sjaak told me, it takes a minimum of 5 years to get the process down in terms of sales projections, orders, and building up a relationship with the cooperages. Also, it takes that amount of time at least to get the recipe right. Not every wine that has oak treatment is made of 100% oaked wine; usually wine that is barrel aged or fermented also has a percentage that hasn't been in a barrel at all to give it freshness and vibrancy. To make a finished wine, wine-makers blend specific proportions of oaked and unoaked wines in order to get the balance of flavours right. In order to choose what is put into barrel, wine-makers will taste the must from different lots (vineyard plots) stored in separate tanks to gauge if they are suitable for barrel aging. Usually this means that they can 'handle' the oak - they're full bodied and flavourful enough to stand up to having an oaky influence too.
In addition, barrels from different coopers have different aromas. I've been sniffing the barrels in the cellar each day I'm down there, and there really is a difference between the types. Some coopers' barrels have a buttery/vanilla aroma, while others have a more spicy/earthy note. Also, there is a consideration of how many brand new oak barrels to use versus old oak barrels, which had wine in it before and lends a subtler and softer oak flavour than new oak. When asked about how to decide what barrels to use for each lot of wine, Sjaak put it this way: "Blending wine from different barrels is like making a curry; you have different spices to hand and you add them according to your taste".
But how do actually treat wine with oak? For whites, Jordan starts fermenting the wine in a stainless steel tank and then transfers it to the barrels via a pump when it reaches a certain Balling (sugar) level, usually when it's been fermenting 3-4 days. We add nutrients to the barrels for the yeast, and the wine finishes fermenting in them.
Long, a permanent team member at Jordan, is pumping finished Merlot into barrels for aging
We also check the Balling levels each day by siphoning off some wine from a random selection of barrels from each lot, measuring them, and then putting the wine back into the barrel. That's been my job for the past 4 weeks since when we started putting wines in barrels and it takes about an hour to do each morning from start to finish.
Siphoning wine from a barrel to take a Balling reading
The yeast lees give the wine a lot of flavour and they and the CO2 that's produced protects the wine from oxidization and spoilage. After the fermentation finished, the barrels are topped up with more wine to protect it from oxidising, as the yeast have finished fermenting and producing CO2, and then they'll roll the barrels once a week so the yeast lees are circulated around the wine. The young wine undergoes malolactic fermentation in the barrel too. This second, natural bacterial fermentation automatically occurs and changes the wine's acidity from malic acid (which is like the acid in a tart green apple) to lactic acid (which is the softer acid found in milk-based things like yoghurt). This makes the wine creamier and more smooth in the mouth.
For reds, the process is much the same although the wine is completely fermented when it's transferred to the barrels. It simply ages in them for a specific number of months.
At Jordan, the approximate barrel aging times are:
Chardonnay - 9 months
Chardonnay in their Nine Yards (premium) label - 12 months
Sauvignon Blanc - 8 months
Chenin Blanc - 7 months
Merlot - 16-24 months
Cabernet Sauvignon - 19-24 months
Syrah - 12-16 months
3 months before the aging is due to finish, the wines will tasted to determine how to blend the finished wine. How much is coming from the barrels and those that were just kept in tanks is a crucial decision. Consistency is important year after year for a given type of wine (say, the oaked Chardonnay), but each vintage is different and thus the wine from a lot could be more acidic, alcoholic, etc compared to the previous year. Blending is a skill and an art.
Jordan's white wine barrel room
I really enjoy going down to the barrel rooms to do the fermentation readings as it's a pretty zen time of the day. The only noise you can hear is the CO2 bubbling away from the special bungs that are placed on them which allow the gas to escape without letting any air in, which oxidises the wine. There is a little recess of water which bubbles up as the CO2 escapes from the barrel as part of the fermentation process. The noise of upwards of a hundred barrels bubbling away is actually quite soothing. Although, one time after we added nutrients to a barrel of newly fermenting wine, the yeasts went a bit too happy, and bubbled up causing the bung to pop up out of the barrel and hit me in the face! Occupational hazard.
Don't put your face too close to the bungholes!