Bartenders Guide: Winemaking
I keep reminding myself that this is a website and not a novel.
Read the Least You Need to Know first, and I'll go a little further here.
Remember: Sugar + Yeast = Alcohol (ethanol) and Carbon Dioxide (CO2). You can get more information on this process HERE.
The Winemaker starts with an idea. A vision, if you will, of the wine he or she wants to produce. Will it be a single varietal grape? Will it be a blend? Is there a suitable growing region, or terroir? Is the wine meant to be drunk young, or aged? If it is aged, will it be aged in wood? There are countless variables.
HARVESTING & CRUSHING
Assuming everything goes as planned and the grapes are harvested, they are then crushed and/or pressed. Crushing is not to be confused with pressing, when the juice is actually extracted. Crushing serves to break the skins of the berry and releases additional tannins and colors into the grape juice. Most white wines are processed without destemming or crushing and are transferred from picking bins directly to the press. This is done to avoid releasing unwanted tannins from the grape cluster and to improve juice flow in the press.
Most red wines derive their color from grape skins and are fermented with the crushed skins. Many white wines are also made from red grapes by pressing the grape and immediately removing the skins. White Zinfandel is made in this manner, from the red Zinfandel grape, with the skins left in just long enough to acquire the desired flavor and color.
Pressing is not always a necessary act in winemaking; if grapes are crushed there is a considerable amount of juice immediately liberated (called free-run juice) that can be used for vinification. Typically this free-run juice is of a higher quality than the press juice. In order to maximize profits and increase production, most wineries will use presses to extract the remaining juice and:
1)Include it in a blend
2)Produce another, lesser-quality wine
3)Sell it to another producer for the same purposes.
With red wines, the MUST is pressed after the primary fermentation, which separates the skins and other solid matter from the liquid. With white wine, the liquid is separated from the must before fermentation . With rose, the skins may be kept in contact for a shorter period to give color to the wine, in that case the must may be pressed as well. After a period in which the wine stands or ages, the wine is separated from the dead yeast and any solids that remained (called its lees), and transferred to a new container where any additional fermentation may take place.
During the secondary fermentation and aging process, which takes three to six months, the fermentation continues very slowly. The wine is kept under an airlock to protect the wine from OXIDATION. Proteins from the grape are broken down and the remaining yeast cells and other fine particles from the grapes are allowed to settle. The result of these processes is that the originally cloudy wine becomes clear. The wine can be RACKED during this process to remove the LEES.
The secondary fermentation usually takes place in either stainless steel vessels or oak barrels, depending on the goals of the winemakers. Unoaked wine is fermented in a barrel made of stainless steel or other material having no influence in the final taste of the wine. Depending on the desired taste, it could be fermented mainly in stainless steel to be briefly put in oak, or have the complete fermentation done in stainless steel. Oak could be added as chips used with a non-wooden barrel instead of a fully wooden barrel. This process is mainly used in cheaper wine.
This is an optional step for winemakers. Malic acid occurs naturally in wine (and other juices) and is very tart. Sometimes this is desireable, sometimes it is not. If not, helpful bacteria are added which metabolize the malic acid into lactic acid, which has a soft, buttery mouth-feel and can add complexity to a wine. Many Chardonnays undergo this process, for example.
Different batches of wine can be mixed before bottling in order to achieve winemaker's desired flavor profile. This may include juice from other varietal grapes, or batches of the same grape grown in different years or under different conditions.
Fining is simply the act of removing any remaining suspended matter, such as tannins, microscopic grape skin particles, etc., that can cloud a wine and cause it to be overly-dry. There are many fining agents, such as gelatin, egg white, etc., but their overall effect is to cause particles to clump and settle for easy removal. Some wines are deliberately bottled un-fined and usually have an especially robust flavor profile.
Filtration in winemaking is used to accomplish two objectives, clarification and microbial stabilization. In clarification, large particles that affect the visual appearance of the wine are removed. In microbial stabilization, organisms that affect the stability of the wine are removed to prevent spoilage and re-fermentation. (Remember, yeast creates alcohol and CO2...fermentation in the bottle would affect the flavor and could cause bursting.) Over-filtration can affect the color of a wine, lightening its color. As with fining, some wines are deliberately bottled unfiltered, and usually have a more robust flavor profile.
By far, the most common preservatives used in winemaking are sulfur dioxide and potassium sulfate. Because wine is very susceptible to spoilage, preservative-free wines are rare, making it difficult for individuals who are allergic to sulfites to enjoy wine.
Often, juices and wines are produced in one location and blended or bottled in another. Click the links below for helpful information.
Bottle vs. Box
Natural vs. Synthetic Corks & Screw-top Enclosures
The Least You Need to Know:
Winemaking, or vinification, is the production of wine, starting with selection of the grapes and ending with bottling the finished wine.
Winemaking can be divided into two general categories: still wine production (without carbonation) and sparkling wine production (with carbonation). Sparkling wine will be discussed HERE.
The science of wine and winemaking is known as oenology (in American English, enology).
The quick steps of winemaking are as follows:
1) After the harvest, the grapes are crushed and allowed to ferment.
2) During this primary fermentation yeast converts most of the sugars in the grape juice into ethanol (alcohol).
3) The liquid is transferred to vessels for the secondary fermentation. Here, the remaining sugars are slowly converted into alcohol and the wine becomes clear(er).
4) Wine is then either allowed to age in oak (or other, such as stainless steel for unwooded wines) barrels or is bottled directly. The time from harvest to drinking can vary from a few months to over twenty years for top wines. However, only about 10% of all red and 5% of white wine will taste better after five years than it will after just one year.