On the redox potential in brewing process. A review

Abstract

Oxidations and reductions are well known to occur in fermentations, thus acetaldehyde must be reduced to give alcohol, of which it is regarded as the precursor. Organic oxidations and reductions can take place either by gain and loss of oxygen or by loss and gain of hydrogen between one substance and another. In this case the transfer of hydrogen and not of oxygen appears to be the more important in biological oxidations, which are balanced by the reductions so that the system as a whole is neither oxidised nor reduced. A bridge between the two substances and motive power to transfer the hydrogen across it may be imagined. The former represents a substance that acts alternately as acceptor and donor of hydrogen, the latter is a specific enzyme or dehydrogenase.