CORNELL
U N I V E R S I T Y 		13Food Science 430
Wine is chemistry, biology and psychology!

Calendar

berry color
acid & sugar
Color.pdf
Slides

Reading: Jackson pp 66-83, 242-251, 281-290, 293-295;
Color Extraction
by Thomas Henick-Kling

    Vineyard Site
    Cultivar Selection
    Vineyard Management
    Grape Maturity & Harvest
    Juice Extraction - color extraction
    Alcoholic Fermentation - color extraction
    Malolactic Fermentation
    Wine Aging (Storage)
Color Extraction

    The color potential is given in the grape, the winemaker has several options on how to extract color (-or not as in the case of production of blanc de noir and rose wines).

    Different red grape cultivars differ in the type and amounts of color compounds (anthocyanins) that they contain. The anthocyanins in Vitis vinifera grapes are bound to only one sugar molecule (glucose). In native American grapes and interspecific hybrid grapes the anthocyanins are bound to one and two sugars (glucose and others). Grape maturity, exposure to the sun, availability of nitrogen, also affect how much color is available in the grape.

    In almost all grapes the color is located in the skin of the berry.

    Control of color extraction by winemaker:
    prefermentation maceration - action of grape enzymes (pectinases, proteinase), SO2

    must pasteurization is an option - at high pasteurization temperatures (70 to 92 degree C) more color is extracted

    fermentation temperature - higher temperature gives more color extraction

    varying the skin contact time after fermentation - longer soaking of the wine extract more color, complexes pigments, it also extracts more astringent flavors (tannins extracted from skins and seeds)!

  FS430 Revised 2.26.01