The wonder of nature has finally made its way to your cellar. The grapes you nurtured and fermented have relented. The bubbles of carbon dioxide have slowed from a turbid percolation to a fine sizzle and the lees have fallen. It’s time to choose a storage vessel, the place where and how your wine will age.
Several choices come to mind at the outset: oak barrels (and tanks), stainless steel, glass, and plastic. Each container can impart a measured benefit to the resulting wine. No container is perfect, but there are some that are better than others.
Oak barrels are the most popular choice for large, quality producers. Oak imparts flavor and structure into wine. Much of oak’s influence occurs as a result of the slow exchange of oxygen and water that mingles with the lignin in the wood.
Depending on the structure of the cells (American, French, Hungarian oak trees are all different) and the toast (light toast = green organic flavors / heavy toast = roasted bold flavors) each barrel can have a drastically different effect on a wine.
There is a concentration of flavors as the wine absorbs tannin from the wood and sheds water via osmosis into the drier air around the barrel.
Because oak is organic in nature it is a permeable container. If stored in a humid environment a lesser amount of concentration occurs within the barrel. If the environment is drier, a greater amount of water within the wine will be lost to the air in the cellar. Warmer temperatures have a similar effect. The amount of wine concentration/loss during a twelve-month period will be minimal, but the barrels should be topped up every few weeks with extra wine.
The benefits of using oak are many, but it is expensive and the influence of the oak is absorbed over only a few years. The oxidative elements of using oak remain consistent even after the influence of the oak has faded, but the barrels must be strictly cared for.
Stainless steel is another great container for wine. Stainless steel barrels, tanks, kegs, ‘fusti cans’ are all airtight and impervious to light. Metal is also a great conductor of heat. And the integrity of the container will never degrade.
On a mass production level, stainless steel tanks are fitted with oak planks and filled with wine. This is an incredible financial advantage over aging wine in new oak barrels. But there’s the initial cost of the steel … it’s not cheap … and there is no oxygen exchange. Without some amount of oxygen wines become reductive, flavors become muted.
There are ways to impart oxygen in the aging process, none are as easy as more frequent rackings. Three to four times before the following vintage. More if the wine requires it.
Glass carboys are a good way to store small quantities of wine but most carboys are not impervious to light. You can find some carboys that are colored, or you could cover or paint the outside of the carboy to rectify this small flaw – just remember that part of the fun of having a carboy is being able to see what’s inside, if there is any lee.
One serious downside to carboys is that they are fragile. When they fall/break/shatter they can be very dangerous. One last thing to think about when considering a carboy is how much wine you are making. If you have 200 gallons of wine, you are not going to enjoy aging it in 40 five-gallon carboys. Having a few on hand helps, but a crowd of carboys is trouble.
Plastic tanks and containers are an option that rivals stainless steel in that plastic is mostly impervious to air and light. Tanks and smaller containers can be fitted with oak alternatives and the wine can be racked, blended, chilled, etc. There is no oxygen exchange, so rackings would be necessary to let the wine breath and mature. But beyond that, there’s not really much wrong with plastic.
The thing with plastic is wholly preferential. It is the bane of producers of massive quantities of brand-style wines. For smaller productions, plastic will work fine for almost any project.
The debate about plastic really begins and ends with those who honor the tradition of wine being the sum of its elements. Plastic is not necessarily as classy as oak, for instance.
For each container there are benefits and drawbacks. No container is perfect, but there are some that are better than others.
Utilizing a mix of containers can be the best strategy for making the best wine possible. Understanding how each container can influence a vintage means having another special instrument in your winemaking toolbox.