Modern Trends in Winemaking

Objectives and competences

Student gets knowledge about new techniques, already used in the wine making
technology, the suitability of their use regarding the wine quality and their influence on
the wine character.

Prerequisites

For understanding of new technologies students has to be familiar with chemistry, physics and basic enology and viticulture.

Content

Lectures

White wine

The white wine technology is now going in to two different directions:

  1. The increase of sort character - especially of the grape sort aroma,
  2. The increase of extractability and stability of white wines (the maturing of wine on the lees or addition of the died yeast cells during the wine maturation).

The increase of white wine sort character

Monoterpens (sort aroma carriers) are found in the grape berry skin and in the grape
mould. They are synthetisised only 7-10 days before the full grape ripeness. The
mission of the technology is to preserve or increase the extraction of these compounds
from the berry skin as much as possible. This can be reached with:

  • Short term cold maceration of de-stemmed white grapes mesh (under 10°C, 6-12 hours). Terpens are bonded to the pectin and sugars with ester bonds. The addition of the pectolitic enzymes with ß-glucosidasic activity is possible to release the bonded pectin or the use of specially selected yeasts (the yeasts aroma) which contain this enzyme. This is how the aroma carriers are released during the alcoholic fermentation.
  • Longer contact between the berry skin and must can be achieved in the process, where 2-3 % of mature berries are added during the fermentation and than removed with the first racking of the wine. Wines, produced by the technology, described previously have extremely expressed sort bouquet, but because of lower fermentation temperatures (below 15 °C) posses less extract. The use of enzymes is recommends for the wines that are consumed in one to two years from the production, especially for the aromatic wines (sauvignon, muškat).

The increase of white wines' extractability

Extractability can be increased by alcoholic fermentation under higher temperatures
(above 20°C), where more glycerol is produced, as well as higher amounts of higher
alcohols (heavy flavor). Because of much intense fermentation and CO2 formation soft
bouquet can be lost and higher alcohols formed during the fermentation can cover the
sort character. Some people in wine trade business say that hiperoxidation of the white
must is the best solution, where already pressed must is oxygen aerated. Added oxygen
enhances the bonding of polyphenols with the proteins. The clarification of the musts is
quicker, higher aeration enables faster multiplication of the yeasts and consequently
larger amounts of glycerol is produced. Addition supply of the oxygen can cause the
monoterpenes' oxidation-which are known as sort aroma carriers. This procedure makes
such wines richer in taste (good maturation) with less expressed sort bouquet. More
recently, especially in the southern Slovenia wine growing parts (in Brda and Koper
region) is for wines, rich in alcohol (above 13 % v/v alcohol), recommended wine
maturation in wooden barrels on the lees (or in stainless steel tanks with periodical
ventilation with oxygen) and stirring the lees. Addition of already dead yeast cells is
possible. Such maturation is going on for 6 ore more months, by stirring the lees 2-3
times per week. Malolactic fermentation happens at this kind of wine maturation (the
transformation of malic acid to lactic acid), from the dead yeast cells (added or in the
lees) yeast proteins are extracted - manoproteins. They are composed from the amino
acids and sugar part-glucose and mannose. The main role of manoproteins is:

  • Wine aroma bonding - preserving for longer period,
  • Stabilization of the tartrates crystallization (a substitute for the metatartaric acid)
  • They prevent the protein haze - by bonding the termo-labile proteins (lesser needs for the bentonite).

Such wines are chemically more stabile, rich on extract, and due to formed lactic acid
softer, fully tasted and well balanced.

Red wines

Carbon maceration:

  • Short-term maceration for young wines such as Beaujolais type,
  • Long term maceration for red wine aging,
  • Prolonged classic maceration.

Short term carbon maceration of the whole clusters, or only
partly stemmed grapes (1/3) is performed in closed
high-pressure tanks with 1-1,5 bar of up-pressure. Released
CO2 during the alcohol fermentation is regulated with the
pressure reducing valve. Alcoholic fermentation is performed
in the berries. Due to hard living conditions, the yeasts are
now forming more fruity higher alcohols, fatty acids and their
esters. Short-term maceration lasts for 2-3 days. The color
compounds are extracted in those period-only anthocyanins but
not other phenols. Such young wines have intense ruby color
tens, fruity bouquets, velvety, a bit tannin and due to CO2,
fresh.

Long-term carbon maceration can last even for 14 days or
more. After 4-5 days, are also tannins (beside anthocyanins)
extracted from skins and seeds. Such wines are rich in
fermentation aroma (heavy aromas from higher alcohols), chewy
and prepared for at least 2-3 years aging. In that period, the
tannins are than condensated, become insoluble, therefore less
tasted and softer.

Prolonged classical maceration, even to one month is performed
at 25-30°C, with "punching down the cap". After the alcoholic
fermentation, when the "cap" of skins is resuspended, the post
maceration is going on, a week or 2, just to finish malolactic
fermentation. These wines preserve more sort character, are
rich in extract and very good for further maturation and
aging.

Integrated wine making

Like in grape growing, there are some limitations also in the
integrated wine making processes, which lower the use of
means, which are bad for human health and also environment and
also lower the environment pollution and
exploitation. Alternative technologies will be presented,
regulations, book keeping of the tracebility, labeling and
marketing of integrate made wine.

Field observations

The visit of highly sophisticated and modern wine cellar is
planned and see practical performance of some new
technological procedures. One world known wine exhibition will
be visited, where some new things, which are implemented in
the wine technology will be presented. (ENOVITIS).

Readings

• Pascal Ribereau-Gayon. 2006. Handbook of Enology (Hardback), Volume 1 in Volume 2. John Wiley & Sons Ltd. Catalogue
• Professional and scientific papers
• Lecture notes

Assessment

Written and oral assignments.

Lecturer's references

Assistant professor for the field of Enology, employed at Agricultural Institut of Slovenia, external coworker at School for viticulture and enology.

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  3. COETZEE, Carien, LISJAK, Klemen, NICOLAU, Laura, KILMARTIN, Paul, DU TOIT, Wessel Johannes. Oxygen and sulfur dioxide additions to Sauvignon blanc must : effect on must and wine compostition. Flavour and fragrance journal, ISSN 0882-5734. [Print ed.], May 2013, vol. 28, iss. 3, str. 155-167, ilustr., doi: 10.1002/ffj.3147. [COBISS.SI-ID 4000872]
  4. JENKO, Mojca, LISJAK, Klemen, KOŠMERL, Tatjana, ČUŠ, Franc. The influence of yeast strain combinations on the quality of sauvignon blanc wine. Food science and technology research, ISSN 1344-6606, 2013, vol. 19, no. 1, str. 7-15. [COBISS.SI-ID 4143464]
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  6. ŠUKLJE, Katja, GOBLER, Nico, COETZEE, Zelmari, LISJAK, Klemen, DELOIRE, Alain. Methoxypyrazines and greenness in wines: myth or reality? : a few perspectives. Wineland, ISSN 1562-7012, May 2013, [6 str.], ilustr. [COBISS.SI-ID 4246376]
  7. ŠUKLJE, Katja, LISJAK, Klemen, BAŠA ČESNIK, Helena, JANEŠ, Lucija, DU TOIT, Wessel Johannes, COETZEE, Zelmari, VANZO, Andreja, DELOIRE, Alain. Classification of grape berries according to diameter and total soluble solids to study the effect of light and temperature on methoxypyrazine, Glutathione, and hydroxycinnamate evolution during ripening of Sauvignon blanc (Vitis vinifera L.). Journal of agricultural and food chemistry, ISSN 0021-8561, 2012, vol. 60, iss. 37, str. 9434-9461. http://dx.doi.org/10.1021/jf3020766, doi: 10.1021/jf3020655. [COBISS.SI-ID 3918184]
  8. JANEŠ, Lucija, LISJAK, Klemen, VANZO, Andreja. Determination of glutathione content in grape juice and wine by high performance liquid chromatography with fluorescence detection. Analytica chimica acta, ISSN 0003-2670. [Print ed.], 2010, vol. 674, iss. 2, str. 239-242, doi: 10.1016/j.aca.2010.06.040. [COBISS.SI-ID 3347048]
    Nagrada: Nagrada za prispevek k trajnostnemu razvoju družbe za leto 2010, Javni sklad RS za razvoj kadrov in štipendije
  9. ŠUKLJE, Katja, GOBLER, Nico, COETZEE, Zelmari, LISJAK, Klemen, DELOIRE, Alain. Manipulating light in fruit zone improves wine quality : winegrowing. Practical winery/vineyard, ISSN 1057-2694, Jan. 2014, str. 27-34. [COBISS.SI-ID 4158056]