In the winery

Although maximum amounts vary from country to country and region to region as well as from different types of wine, the goal is to reduce sulphur levels to create a healthier product that is still stable. Sulphur dioxide is allowed in very restricted amounts, the Directive 87/822/EEC setting maximum levels as shown in Table 11.1. 

According to E for Additives, sulphur dioxide (E220) occurs naturally but is produced chemically by the combustion of sulphur or gypsum  

One of the most salient points about organic winemaking is the parallel between them and the makers of fine wines in general. Both groups follow the guidelines below  

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Addition of up to 200 ppm sulfur dioxide to grape musts is customary. Strains of S. cerevisiae and S. bayanus grown in the presence of sulfite, become tolerant of fairly high concentrations of SO2. Cultures propagated in the winery are added in Hquid suspension, usually at 1—2% of the must volume. Many strains are available in pure culture. Factors such as flocculence, lack of foaming, fast fermentation, lack of H2S and SO2 formation, resistance to sulfur dioxide and other inhibitors, and flavor production will affect strain choice. No strain possesses all the desired properties. 

A small diameter pipe 32 m long runs from the fermentation room of a winery to the bottle filling cellar. Sometimes red wine is pumped through the pipe, sometimes white, and whenever the switch is made from one to the other a small amount of house blend rose is produced (8 bottles). Because of some construction in the winery the pipeline length will have to be increased to 50 m. For the same flow rate of wine, how many bottles of rose may we now expect to get each time we switch the flow ... 

Even when no additive is used in winemaking, the necessity for small-lot trial before production scale operation is apparent. Because a high percentage of wine is consumed only after chilling, and because chilling may accelerate the precipitation of potassium acid tartrate, ill-defined colloids, anthocyanin-tannin polymers, proteins, etc., simple cold stabilization by refrigeration in the winery may irreversibly alter the product and its eventually-perceived quality level. It often happens, especially in heavy-bodied red varietal wines, that a dark, amorphous precipitate may form in the bottle over several years. Usually tannoid,... 

Check Lists. Tables I and II list groups of quality control check points which should be monitored for each wine lot during the corresponding phases in the winery. The quality control manager should... 

Temperature. Check the use of ventilating systems to see that they are open only when the outside air is cooler than the inside air. Be sure that lights near the ventilator openings are not left on since this can attract insects during the night. Walk through every room in the winery every day. 

It is of interest to note the amount of hand labor required in pre-Prohibition wineries. Crushers often were placed at the highest point in the winery, the fermentors were on the top floor, and storage tanks were on lower floors. It was not until the 1890s that machine-operated pumps and filters were used commonly. Grapes, of course, were still delivered in boxes and unloaded by hand and the pomace was removed from the fermentors by hand labor, in a few cases until recently. 

Prior to 1960, few made any attempts to control the malo-lactic fermentation in red wines. Ingraham et al. (19) showed that there were at least five types of lactic acid bacteria capable of decomposing malic acid in California wines. Webb and Ingraham (20) showed that the malo-lactic fermentation could be induced in the winery. Prior to that time, most malo-lactic fermentations occurred spontaneously from the inoculum normally present in the vats. 

In the Winery. To maintain the malo-lactic culture in an active state in wine, it has been found necessary to have the wine at a temperature in excess of approximately 65° F (18.33° C). In red wines, this is accomplished most often by inoculating the wine immediately after separation from the pomace (skins, pulp, and seeds). This separation generally is performed at five percent to eight percent soluble solids as indicated by a Brix hydrometer. There is often enough heat of fermentation generated to allow completion of the malo-lactic fermentation. 

The care and development of a wine is by no means terminated when the wine is bottled. Once bottled, the development of the wine is evidenced first by the disappearance of bottle sickness followed, over a longer period of time, by the development of maturity and complexity of the wine within the bottle. Having the wine in the winery during its early stages of development also affords the winemaker the opportunity to be assured of the sterility of cold-sterile bottled wine. 

Krieger, S.A., Hammes, W.P., Henick-Kling, T. (1993). How to use malolactic starter cultures in the winery. Austral New Zeal. Wine Indust. J., 8, 153-160. 

Control of Ce compounds formation is normally achieved in the winery through careful clariflcation prior to alcoholic fermentation (Dubourdieu et al. 1986), as well as through removal of stalks and leaves, which have been shown to be a major source of these compounds (Cordonnier Bayonove 1981). 

Control of bacteria development is essential for the production of wines with consistent compositional and sensory characteristics. Although malolactic fermentation (MLF) is frequently carried out in the winery due to its beneficial effects on wine aroma and palate, for certain grape varieties and wine styles MLF is considered detrimental. Moreover, even in the cases where MLF is desirable, the wine might... 

Finally, as Martini and Martini (5) note, the selective pressures at work in the winery environment may influence the survivability of the indigenous yeasts with respect to ethanol or sulfur dioxide tolerance it is not clear, however, how such environmental pressures would be selecting for desired flavor production. Certainly few winemakers completely sterilize their wineries and scorch their vineyards when they obtain a wine with less than optimal flavor attributes ... 

Brettanomyces and barrels. Another problem of Brettanomyces detection in the winery is large variations in bairel to barrel populations. In a 45 week barrel sampling study of stored Cabernet Sauvignon wine. Blazer and SchleuBner (54) determined it was necessary to stir barrels before plating to acquire accurate cell counts of Brettanomyces. Measured populations increased after stirring -- in some cases by 10-fold or more in others, detection depended on stirring. 

Enologists must have available to them as much information as possible when buying barrels to produce high quality matured wines, although economic factors must not be forgotten. French oak barrels cost almost twice the price of American oak barrels and large volume barrels save space in the winery. 

The same types of mold (particularly Penicil-lium) may find a similar environment (humidity, temperature, presence of chlorinated derivatives, etc.) in cork as well as wooden containers and structures in the winery. This explains the possible confusion between authentic cork taint and moldy off-flavors , which have similar smells, but different origins. When cork is responsible, only a few bottles are affected, whereas all the bottles may be spoiled if the defect is of external origin. 

Table 8.13. Demonstration of the dual contamination of a red wine by the atmosphere in the winery and the cork (wines bottled on the same day with a single batch of corks, analysis carried out after 12 months, results in mg per bottle or per cork) (Chatonnet et al., 1994)...

The most important requirement in cellar work is cleanliness in the winery and hygiene in all containers (Peynaud, 1975). Wine gives the impression of a certain stability, due to the presence of alcohol and relatively high acidity. In fact, it is sensitive, not only to microbial deterioration but also to various types of contamination that may give the wine unpleasant odors and off-flavors that are impossible to eliminate. Cleanliness in all winemaking operations, from fermentation to bottling, is an indispensable prereqnisite for qnality. 

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