In parts 1 and 2 we covered from after the grapes harvest through fermentation. This post will cover cellar aging and bottling. I am going to focus on still wines. Sparkling wines deserve their own post.
If we are going to talk about cellar aging we should take a look at why wine is aged. Wine is a complex mixture of organic chemicals, some gasses, minerals and biologic material (mostly yeast). All of these things interact with each other. These interactions change the nature of the wine. I liken it to a piece of fruit. Some fruit is just fine when it is first picked. Some is best if it sits for a little time. After a while all fruit is past its prime, though it may still be edible for some of that time. With wine the time scale is different but the idea is the same.
Some wines are not aged in the cellar but are bottled as soon as fermentation is complete. This is common for whites and roses but also the case with some reds. Wines can be aged for anywhere from weeks to years. How long is governed by traditions, the laws of the area, and the winemaker’s preferences.
Most wines that are aged for more than a few months are aged in wooden vessels. Most wooden vessels are made from oak with chestnut also being used in some areas. Wooden vessels are preferred because they have been found to work well. Wooden vessels are not entirely air tight. A very small amount of air can enter the wine over time. While lots of air will allow a wine to oxidize (a bad thing), small amounts have been found to be good.
A second important reason why wood can be good is the wine will interact with the wood itself. How much it interacts depends on a few things. The first is how big the vessel is. Smaller vessels have more surface area of wood to the volume of wine than bigger ones. Small barrels are made specifically to take advantage of this. The most typical is around 225 liters and is known as a barrique.
Barriques are made from oak and wine makers can get very fussy about where the oak comes from. Oak from the southwest of France, The northeast and midwest of the US, and Slovenia are held in high esteem. Another factor in how the wine interacts with the wood is how many times the barrel has been used. The fewer times, the more the wood affects the wine. Barriques are usually used for a maximum of three or four times.
There are two big interactions that wine has with wood. The first is wood has tannin in it. Some of the tannins can dissolve into the wine. The second are there are some flavors in the wood that can get into the wine. A common one found in white wines tastes like vanilla. Smokey or toasted flavors can happen too.
When a winemaker determines it is time to bottle or otherwise put the wine into the containers in which it will be sold there are a few decisions to make: Filtering, container, and the stopper to use.
Wine naturally has particles suspended in it, bits of grape, yeast and the like. With time most will settle out. The winemaker can add material to help this along, everything from egg white or clay to powdered fish bladder (isinglass) or plastic pellets. These are called flocculants and don’t filter the wine.
These days most wine is filtered. There is a delicate balance in filtering. Filtering makes a wine cleaner tasting and clearer. It can help it age in the bottle by removing undesirable things. The flip side is that any filtering will remove some flavor. Except in some bottles that are labeled as unfiltered, you are unlikely to find much information on how a wine is filtered without doing some research. Even then you most likely will not find out.
Wine is put into any number of kinds of containers, everything from tanker trucks to bottles. Most wine you buy retail is either in glass bottles or is “box wine”. I have nothing against boxed wine. It can be a good way to get wine less expensively. The only caveat is that I don’t like having my wine in contact with plastic for a long time and would prefer wine that is recently boxed and that will be quickly drank. That said I have sentimental attachment to bottles.
The stopper question deserves its own post and is endlessly debated. In brief, your choices are bottle caps, plastic stoppers and a variety of corks. Cork is traditional for wines that are going to be stored for more than a year or so.