Wines botrytized sweet

Sipiczki, M. (2003). Candida zemplinina sp. nov., an osmotolerant and psychrotolerant yeast that ferments sweet botrytized wines. Int. J. Syst. Evol. Microbiol. 53, 2079-2083. 

Abstract Botrytized wines are natural sweet wines, produced from grapes... 

The main difference between botrytized wines and other nonfortified sweet wines, for example, late-harvest wines, icewines (eiswein), or straw wines, is the extreme range and richness of the aroma compounds produced by Botrytis. Marked differences also exist in some other components (e.g., glycerol, acid composition), due to the microbial activity. According to the descriptors most often applied to these wines, they are characterized by peach, apricot, pear, quince, raisin, and honey flavors, combined with distinctive "botrytis or roti aspects. Another typical feature of botrytized wines is their high acid contents. These prevent them from appearing cloying, even if the sugar content is commonly over 200 g/1. 

The high prestige and superb quality of botrytized wines has inspired many winemakers, both within and exterior to Europe, to encourage noble rot and produce botrytized sweet wines. 

The ratio of the two enantiomers of 3SHA was only determined in dry wines as this compound is never present in sweet, botrytized wines. The distribution of the two 3SHA enantiomers (R S) in dry wines was approximately 30 70 for both grape varieties studied (Table 8B.7). 

Dry white wine Sweet white wine (botrytized) ... 

On the basis of these findings, DMDC was initially authorized in the United States, then in other countries. Like ethyl pyrocarbonate, DMDC is most effective at the time of bottling, although it has also been suggested for use in stopping the fermentation of sweet (botrytized) wines (Bertrand and Guillou, 1999), thus reducing the amount of SO2 required. In any case, a certain quantity of free SO2 is always necessary to protect the wine from oxidation. 

Beside Eszencia and Aszu, Tokaj specialty wines include three more types, Forditas, Maslas, and Szamorodni (Eperjesi, 2010 Kirkland, 1996). Szamorodni (meaning "as it was bom") is the most internationally well known. In vineyard sections where the selection of botrytized berries is unprofitable because of their limited presence or adverse weather conditions, noble-rotted and sound berries are harvested together. Vinification follows standard procedures, typical to other white wines. Depending on the initial sugar content of the must, the resulting wine is sweet or dry and is matured for 2 years (at least 1 year in oak barrels). 

Another style of botrytized sweet wine from France involves the category of "Selection de Grains Nobles" (SGN). This legal definition was introduced in 1984 in Alsace, but similar wines are produced also in the Loire valley from grapes of different varieties and sugar contents (Table 6.2). 

In California, the environmental conditions typically do not support the development of noble rot. Nonetheless, a few wineries are occasionally able to produce botrytized sweet wines, mainly by vineyard inoculation of grape clusters with Botrytis spores. 

The artificial induction of noble rot would greatly facilitate making botrytized sweet wine, extending their production to countries where conditions are unfavorable for the natural development of noble rot. Experiments have long been performed to this end. In the earliest work, Nelson and Amerine (1956) unsuccessfully tried to induce its development in the vineyard by inoculation. The necessary moisture condition after inoculation was impossible to reproduce under field conditions. In addition, the method creates the risk that other fungi (Penicillium, Aspergillus, Rhizopus), yeasts and, acetic acid bacteria could develop if unfavorable weather conditions arose (Dittrich, 1977). 

With a few exceptions (Nisiotou et al., 2007), Saccharomyces strains dominate fermentation sooner or later, as in nonbotrytized wine. A special feature of botrytized fermentations is that, beside various S. cerevisiae races, S. uvarum (formerly known as S. bayanus var. uvarum) is typically isolated from these wines (Antunovics et al., 2003 Magyar et al., 2008 Minarik and Laho, 1962 Naumov et al., 2000, 2002 Sipiczki et al., 2001 Tosi et al., 2009). This species seems to be well adapted to sweet wine fermentations, particularly, but not exclusively, in cooler climates. 

Nelson, K. E. and Nightingale, M. S. (1959). Studies in the commercial production of natural sweet wines from botrytized grapes. Am. J. Enol. Vitic. 10,135-141. 

Sarrazin, E., Shinkaruk, S., Tominaga, T., Bennetau, B., Frerot, E., and Dubourdieu, D. (2007b). Odorous impact of volatile thiols on the aroma of young botrytized sweet wines Identification and quantification of new sulfanyl alcohols. /. Agric. Food Chem. 55,1437-1444. 

The development of maturity and complexity of the wine is a relatively slow process. While we occasionally observe significant increases in these characteristics in as little as three months, it is more common to find increases in maturity and complexity over time spans measured in years. Some of the white wines of the Northwest are allowed to mature in the bottle for up to one year prior to release for sale. These wines are usually either sweet or are truly dry white wines. Typical examples would be botrytized or late harvest White Rieslings and Chardonnays. The red wines of the Northwest generally are aged in the bottle for one year or more prior to release. A notable exception in recent years has been wines of the V. vinifera cultivar Merlot, offered by several wineries in Washington with six months or less bottle age. 

In a survey of commercial wines from the South of France, levels of pallidol and viniferin have been reported. Viniferin was found to be present in red and botrytized sweet white wines with levels between 0.1 and 1.63 mg/L. Pallidol was not found in dry and sweet white wines but only in wines made by maceration with stems, with levels between 0.38 and 2.22 mg/L (Landrault et al. 2002). 

The addition of thiamine is legal in several countries (EU, at a dose of 50 mg/hl) but it is rarely used to accelerate fermentation in winemaking. It effectively decreases significant ketonic acid concentrations by decarboxylation (pyruvic and a-ketoglutaric acid). Large quantities of these acids bind to sulfur dioxide in botrytized sweet wines (Section 8.4.2). 

Considering these phenomena, the addition of SO2 to a fermenting must should be avoided. It would immediately be combined without being effective. When the grapes are botrytized, the variation in the ethanal content of different wines when 50 mg/1 of SO2 is added to the must accounts for a combining power approximately 40 mg/1 higher than that of non-sulfited control wines. When stopping the fermentation of a sweet wine, a sufficient concentration should be added which... 

Table 8.13. Influence of temperature on the state of sulfur dioxide (mg/1) in a botrytized sweet wine (sugar 74 g/1 ethanal 70 mg/1)...

The oxidation affecting sulfurous acid forms sulfuric acid. At the pH of wine, it is almost entirely in the form of sulfate. In botrytized and non-botrytized sweet wines with elevated free SO2 concentrations, a considerable amount of sulfate can be formed (0.5 g/1). Less is formed in dry white and red wines, especially those stored in tanks. In the case of barrel-aged wines, the formation of sulfate by the oxidation of free SO2 accumulates with the amount resulting from the combustion of sulfur in the empty barrels. This formation lowers the pH and harshens the wine. This phenomenon contributes to the decrease in quality of wines stored in barrels for an excessively long time. 

The taste improvement due to ascorbic acid depends on several factors. The first is the type of wine. Ascorbic acid is of little interest in the case of wines made from certain varieties or very evolved wines—for example, barrel-aged wines oxidized white wines, botrytized sweet wine, and fine red wines. On the contrary, it improves the stability of fresh and fruity wines (generally young wines), having conserved their varietal aromas. 

In conclusion, each type of winemaking contains a key phase during which the decisions of the winemaker have a determining and almost irreparable effect on wine taste vatting for red wines pre-fermentation operations for dry white wines and noble rot development and picking conditions for botrytized sweet wines. 

The biology of Botrytis cinerea and its development in the form of noble or vulgar rot have been described in (Section 10.6). This overripening process, noble rot, permits the production of great botrytized sweet wines. These exceptional wines can only be made in specific conditions. Their production is therefore limited. 

Sulfiting juice intended for botrytized sweet wine production has often been criticized. This operation leads to increased concentrations of bound sulfur dioxide, which remains definitively in the wine. Subsequent SO2 additions must therefore be limited to remain within legal total SO2 limits, thus compromising the microbiological stabilization of wine. In practice, this inconvenience of sulfiting is attenuated by the fact that only 40-60% of the SO2 added in juice is found in the bound form in wine. The rest is oxidized into SO3. 

As with dry white winemaking, overclarification can lead to large fermentation problems and increased acetic acid production. Must turbidity should not be as low as in dry white winemaking (100-200 NTU) 500-600 NTU or even a slightly higher turbidity is perfectly acceptable. Moreover, botrytized sweet wines are not subject to the same problems related to insufficient clarification as dry white wines—the development of reduction odors and vegetal tastes, oxidability, etc. 

The organoleptical quality of botrytized sweet wines improves considerably after several months of barrels maturation and several years of bottle aging. The bouquet takes on finesse and complexity—reminiscent of confect fruit and toasted almonds. The wine becomes harmonious on the palate. The sweetness is perfectly balanced by the alcohol and a note of acidity gives a refreshing finish. The wines are not heavy and syrupy, in spite of their high sugar concentration. These transformations remain poorly understood even today. They occur in conditions, particularly oxidation-reduction conditions, reminiscent of red wine maturation and aging. 

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