There are many different processes involved in making wine. Of course, to make great wine, you need to start with great grapes. These are the raw materials which we ferment into our beloved wine. However, high quality grapes do not necessarily mean high quality wine. The winemaker, like the vineyard manager, has many important steps to follow and techniques to use to turn those grapes into great wine. This is a really unique industry because in the winery it is a beautiful balance of science and art. There is style to winemaking, and each winemaker and sometimes region has a unique stamp from its maker. There are some general procedures that must be followed in all cases, and these are outlined below. This is in no way an exhaustive overview of how wine is made. There are many complex techniques that can be used, and research in the area of winemaking is continually expanding and improving upon our current knowledge base. This is a great starting point to learn how wine is made, and to build an even greater appreciation for the wines that you love.
- Grape Processing
In the wine world there are a couple of important days in the year, but one day stands out above everything: the day of the beginning of harvest. The date of harvest plays a big role in determining the style of the future wine. The process of making wine starts when grape clusters are harvested by people or by machine. When the grapes enter the winery, the first step is sorting them and trying to use the best quality grapes for the future wines. The most widely used sorting technique is hand sorting, where people stand around a long rolling table and sort the grapes by hand. However, just as technology is taking part in all aspects of our life, technological advancements have been implemented into the wine industry too. Today wineries use an optical grape sorter, which can quickly and efficiently sort grape berries by size,colour, and more. Grape berries can also be sorted based on density, where the berries enter a sugar water solution, and depending on the density (ripeness) or the grapes, they will either be selected or rejected. The grapes that meet the winery’s quality criteria after sorting go on to be crushed to release the grape juice and move into a vat where the “miracle” and converting juice into wine will be performed.
The first and main type of fermentation that occurs in the winemaking process is alcoholic fermentation. This chemical reaction utilizes yeast to convert the grape sugars (glucose and fructose) into alcohol (ethanol) and carbon dioxide. Alcoholic fermentation can start in two ways: spontaneously or by inoculation of commercial yeasts. Naturally, yeast are located on the skin of the berry, and with the right conditions it can start alcoholic fermentation without the need for additional yeast. Some wineries use this method to increase the complexity of their wines, to express their terroir, or to save money by not purchasing commercial yeast. Other wine producers choose to select the yeast that will be used to perform alcoholic fermentation, thereby giving greater control and predictability to the resultant wine. There are some pros and cons of spontaneous fermentation compared to inoculating the grape must. Spontaneous fermentation can increase the complexity and authenticity of a wine, save money, and potentially be marketed as a more “natural” wine. On other hand, there are much greater risks involved with a spontaneous fermentation. The chance of having a stuck or slow fermentation, undesirable aromatic compounds, and having a resulting wine style not in line with your goals are cons. By adding yeast (inoculation) we ensure that alcoholic fermentation will finish converting sugar into alcohol without the production of any undesirable aromatic compounds.
Malolactic fermentation (MLF) is the second type of fermentation that can be performed on a wine. In this process, malic acid is converted into lactic acid by the action of certain bacteria (Oenococcus oeni). Malic acid is a harsher acid present in the wine, and by converting it into lactic acid the wine becomes softer and less tart. MLF can happen after alcoholic fermentation or simultaneously. Not all wines go through MLF, because this process has significant effects on the wine style and the aromatic and flavour profile of the finished wine. Most red wines will undergo malolactic fermentation to round out the flavours, and typically only bigger style white wines will go through malolactic to give it that buttery creamy taste. MLF typically occurs alongside barrel aging, thereby adding even greater complexity to these wines.
After finishing alcoholic fermentation, it is time for the process of ageing. Ageing can be short or long, and can be done in wooden barrels , inox vats, concrete vats, bottles, amphoras and more. The main goal of ageing is to increase the quality and complexity of the wine. The decision of how long to age a wine and in what vessel, depends on a couple of factors. Chemical analysis of the wine (for pH, alcohol, phenolic compounds, etc.), the market cost of the wine, and the winemaker's vision are all factors that influence how a wine will be aged. The most commonly used practice of wine ageing is ageing in oak barrels. The type of oak and the size of the barrel can differ, but the most common origin of the oak species are French and American oak, but other species like Hungarian oak or acacia are possible as well. The difference between the species of oak mainly has to do with the grain of the wood. American oak is more dense and typically imparts sweeter characteristics to the wine such as vanilla and coconut, while French oak is usually a bit softer and imparts more subtle and elegant notes to the wine because it has tighter grains. The barrels can be toasted to different levels as well, and the age of the barrel (new oak or 1 or 2 year old barrels) will also influence how strongly that wood is felt in the wine. In addition to the characteristics of the oak (species, age, level of toasting), the influence of the oak barrels on wine depends on the length of ageing, the size of the barrel, and the conditions of ageing. Some of the outcomes of ageing in oak barrels are clarification of wine, changing colour, changing aromatic profile, “softening” wine and many more.
Wine could age up to 3 years in oak barrels, depending on style.
When ageing is finished, preparation for bottling begins. Before wine goes into the bottle it goes through a couple of different processes. The process of stabilization is one of the most important, especially for white wines. In white wines we perform two types of stabilization (protein stabilization and tartaric stabilization) while in red wines we just perform one stabilization (tartaric stabilization). After stabilization, most wines go through a process of filtration, to remove any residual substances that could be in the wine. Once the wine is clear, it is time for bottling. Most of today’s bottling machines work on similar principles. Bottles are washed at the beginning of the line and filled with nitrogen to protect the wine as much as possible. Then the bottles are filled with wine in a completely anaerobic environment, and closed and labeled at the same time. Before going on the market, it is recommended to wait around 6 months so that the wine has time to adapt to the glass bottle. At this time, you are able to purchase these wines from your local wine shop, winery, or supermarket and to take it home to enjoy with your friends and family!
If you want to learn more about the different processes that happen in the winery, become a member of Enomotion Wine Club! We will provide you with all of the information and knowledge that you need to feel confident about what you drink, and to learn to appreciate it in a new and unique way. Get started on your wine journey today!