Microbiology 4- Alcoholic Fermentation

  1. In wine fermentation, what is 'must'?
    Juice and pomace
  2. What is pomace?
    Solid residues: skins, seeds, stems
  3. What is racking?
    Wine is separated from the lees (sediment of yeast and grape material)
  4. How is white wine made?
    • 1. Stems removed from grapes
    • 2. Juice sits in contact with skins for4 16-24 h (add SO2)
    • 3. Press (discard pomace)
    • 4. Fermentation vat (10-15 days) add yeast
    • 5. Aging (5 months)
    • 6. Clarifying agents (filtration or centrifugation)
    • 7. Bottling
  5. What are the steps to make red wine?
    • 1. Stems removed, grapes crushed
    • 2. Maceration and fermentation (vat is not removed), SO2 and yeast is added
    • 3. Press (pomace discarded)
    • 4. Aging in barrels
    • 5. Add SO2, transfer to clean barrels 3 times per year
    • 6. Clarifying agents or filtration and centrifugation
    • 7. Bottling: aging in bottles 6 months or more
  6. What are the grapes used in wine making?
    Vitis Vinifera
  7. What are some of the main varieties used in white-wine making?
    Chardonnay, Muller-Thurgau, Riesling, Sauvignon Blanc, Semillon, Traminer
  8. What are some of the main grape varieties used in red wine making?
    Barbera, Cabernet Franc, Cabernet Sauvignon, Gamay, Grenache, Merlot, Pinot Noir, Shiraz
  9. Why is SO2 added to the must during prefermentation?
    To kill the wild yeasts
  10. What are the three options for clarifying white wine?
    • Pectolytic enzymes added to break down grape material (pectin)
    • Filtration
    • Centrifugation
  11. SLIDE 9
Card Set
Microbiology 4- Alcoholic Fermentation
Microbiology 4- Alcoholic Fermentation