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Why does salt and ethanol affect CO2 production in fermentation?

  1. Feb 19, 2008 #1
    Why does salt and ethanol affect carbon dioxide production in the fermentation process of sucrose?

    Is it because the yeast has to break the sugar down by hydrolysis and that ethanol and salt are soluble, thus, in 'competition' with the yeast because they are occupying needed water molecules? or am I way off? Any help would be greatly appreciated.
  2. jcsd
  3. Feb 19, 2008 #2

    jim mcnamara

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    Staff: Mentor

    Fermentation usually involves yeast.

    To give an answer from a human standpoint: yeast produces ethanol as a byproduct of fermentation. Concentrated ethanol denatures cell proteins, yeasts stop fermentation when the level of ethanol reaches from ~8% > ~12% depdning on the yeast culture.
    Yeasts avoid killing themselves off in their own byproduct.

    Salt in reasonable quantities, causes exosmosis in yeast cells, they become less effective. At high enough concentrations the yeast cells lose so much water they cannot function. High concentrations of salt as brine and sugar as syrup work the same way, and are used as preservatives. Alcohol can be used to preserve food, but it changes proteins' appearance, so alcohol-pickled foods look, um, weird.
  4. Feb 19, 2008 #3
    Thanks Jim, do you know any good web sites I could visit?
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