Wine fermentation types

Clarification and Stabilization Combinations. Wine clarification may be combined with a stabilization step to minimize handling of the wine. This type of clarification, timing, and sequence vary from winery to winery. Some options used are, after fermentation, rack the wine off yeast lees, bentonite fine for heat stability and chill for cold stability, then diatomaceous earth filter to remove remaining yeast, bentonite, and tartrate crystals after fermentation, centrifuge the wine to remove yeast solids, then chill and add bentonite, and filter to remove yeast and add bentonite, chill, then pad filter to remove bitartrates and protein. 

Herraiz, X, Reglero, G., Herraiz, M., Martinalvarez, P. J., Cabezudo, M. D. (1990) The influence of the yeast and type of culture on the volatile composition of wines fermented without sulfur-dioxide. American Journal of Enology and Viticulture, 41, 313-318. 

The direct reaction between anthocyanins and hydroxycinnamic acids readily explains the formation of anthocyanin-vinylphenol-type adducts in red wines. At the time of writing, this is the only experimentally verified mechanism leading to the development of 4-vinylcatechol and 4-vinylsyringol pigments, as the free vinylphenols have neither been detected in wines nor was it possible to generate these compounds via enzymatic decarboxylation using yeasts commonly applied to red wine fermentation... 

Port-type ted dessert wines require skin contact time to extract the anthocyanins, but the fermentation must be short to retain the sugar level neat the 6—10% level desired. The winemaker cannot always achieve desired composition in individual lots. In order to teach the desired standard, it is necessary to make new lots to enable blending to that standard. The right volume of a tedder, less sweet wine will need to be made to bring to standard a lot with low color and mote sugar, for example, while keeping the alcohol also within the desired limits. 

Careful records must be kept to enable verification of compHance. Each lot of wine must be traceable back to the grapes and vineyard. Tanks must be carefully gauged and the capacities recorded on them. If the wine is to be labeled "estate botded," not only must the wine be fermented, processed, and bottled by the state winery at thein Hsted address, but the vineyard must also be owned or controlled by that winery. Other label terrninology, subject to some further intricacies, are "produced," ie, fermented 75% or made into a different class of wine "prepared," "vinted," or "cellared," ie, subjected to ceUar processing or aging without changing the class of wine "blended," ie, combined at the stated address, wines (probably purchased) of the same class and type and "botded" or "packed" by the stated winery. 

The optimum temperature of fermentation of wine depends on the type, red wines working best at about 29°C while the white wines require a cooler condition of around 16°C. Heat is given off by the chemical process of fermentation. They are then traditionally matured and stored in caves or cellars at about 10°C. Much of the manufacture... 

The catalytic capacity of several excreting pectolytic enzymes obtained from various yeast strains was examined using in vivo and biochemical techniques. Of the 33 yeast strains studied 30 were isolated from champagne wine during alcoholic fermentation. Only one yeast strain was found to excrete pectolytic enzymes and was identified as Saccharomyces cerevisiae designated SCPP. Three types of pectolytic enzymes were found to be excreted by SCPP polygalacturonase (PG), pectin-lyase (PL) and pectin-esterase (PE) [1]. 

It was obvious from Pasteur s studies that each special kind of fermentation or disease of beer or wine was the result of the growth and activity in it of a special, distinct form of yeast or other microorganism, depending on the type of fermentation or disease under investigation. This furthered an idea, already old, of the specificity of biological action, and supported the view that animal and human diseases also, like different sorts of putrefaction and fermentation, were each caused by a single, specific type of microorganism. 

Suppose we are interested in investigating the effect of fermentation temperature on the percent alcohol response of the wine-making system shown in Figure 1.6. We will assume that ambient pressure has very little effect on the system and that the small variations in response caused by this uncontrolled factor can be included in the residuals. Further, we can use the same type and quantity of yeast in all of our experiments so there will be no (or very little) variation in our results caused by the factor yeast . 

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