After harvest, bottling is the most important and risky operation in the winery. Often overlooked by consumers and commentators, the bottling process involves meticulous planning and preparation to avoid mistakes and ensure the wine reaches the consumer in the best state possible.
Large wine producers have dedicated bottling facilities that run all year round, much like a brewery or soft-drinks factory, but for the thousands of independent family estates, bottling is a stressful event involving lots of third-party help. Like many small producers in my region, I do not own a bottling line. I have to reserve a mobile bottler several weeks in advance.
Every winery has different criteria and constraints when it comes to bottling, depending on the type, range and volume of wines to be bottled. So much of this article relates to how I approach bottling at Domaine Treloar.
We produce around 35 000 bottles a year of white, rosé, red and sweet fortified wine. Each of those wines has different ageing requirements, so I plan three bottling days during the year.
The mobile bottling chain that I use can bottle up to 14,000 in a day. Limited storage space and truck access mean that I cannot easily bottle two days in a row.
My first day, usually between February and April, will be for the tank-aged white, rosé and fortified wine of the previous harvest plus a couple of red wines from the year before which have been aged in barrel and tank for 18 months since their grapes were picked.
Then I will plan two more days for both barrel-aged wine from two years ago and tank-aged wine from last year. Like every other small winery, we need to make sure our tanks are empty before harvest.
Some of my wines are unblended and simply require preparing but some of the reds are blends of several varieties that have been aged in different barrels and tanks.
Planning, testing and carrying out the blends is quite a complex exercise in itself and needs to be done in good time to know the volumes, analyze the wine for alcohol content and print the correct quantity of corresponding labels.
Wines that I keep in tank have high levels of carbon dioxide left over from fermentation.
This excess gas needs to be reduced to avoid having fizzy wines in bottle. We do this by sparging the wine with nitrogen gas until the level of dissolved CO2 is correct. White wines generally contain 30% more CO2 than red wines as it helps to keep them fresh and lively.
Once the wines have been blended and sparged, they may need to be clarified or stabilized. I am on the natural spectrum of winemaking, so I tend to avoid these steps unless really necessary.
White wine can contain invisible proteins which, if subjected to heat in the bottle, can turn cloudy. Conversely, crystals of potassium bitartrate can form in the bottle, creating a crystalline sediment, when the wine is chilled.
The proteins can be removed by the addition of Bentonite clay and the potassium bitartrate forced to form in tank by chilling. In all cases, the wine is racked or sediments filtered off and homogenised in a tank ready to bottle.
At the same time, I need to make sure I have ordered enough bottles, corks, capsules, cartons and labels for the various wines to be bottled.
Bottles may vary in volume, colour and shape according to the wine. Capsules (at least for the regulated French market) need to correspond to the type of wine as well as be visually attractive.
Corks may vary depending on how long the wine is expected to age in bottle. I use the same type of carton and print the name of the wine at bottling but other wineries may use different cartons for different wines.
Labels are the most important part of the packaging. Lots of consumers buy wines based on the label and there are several legal pieces of information to get right. All wine labels in France need to show the alcohol level, the volume, the official category of the wine and the place of bottling.
They may show other variable details such as vintage, name of the wine and producer, drinking dates and barcodes. Each of these things needs to be checked before printing to avoid the painful cost of having to rebottle.
Finally, workers need to be hired and space made for the twenty or so pallets of bottled wine.
Once all the little things are ready, the day of bottling arrives. The machinery needs to be set up and sterilized.
The filtration pads are selected, depending on the type and stability of the wine and rinsed with water. Wine is then passed and rotated through the filter until it tastes like that in the tank. Finally everything is ready to start filling the bottles.
Bottling is a long, hard day of monotonous work where everything needs to be constantly monitored, such as making sure the appropriate labels are applied correctly to each bottle, that the level of wine in the bottle will be the correct volume, and ensuring no oxidation of the wine occurs during its flow from the tank to the bottle.
At the end of the day, when the tanks have been washed and all the packaging waste tidied up, there is a great sense of relief and pride in the pallets full of cartons of bottled wine all waiting to be sold and enjoyed.
Jonathan Hesford has a Postgraduate Diploma in Viticulture and Oenology and is the winemaker of Domaine Treloar in the Roussillon – www.domainetreloar.com
If you have questions on this column, email him at email@example.com