The micro-organism splits up the laevulose in the must, forming mannitol and different acids, particularly volatile acid.
The freshly-expressed yeast juice causes concentrated solutions of cane sugar, glucose, laevulose and maltose to ferment with the production of alcohol and carbon dioxide, but not milk-sugar and mannose.
The following figures obtained by Mach afford an interesting illustration of these processes At first the sugar in the juice consists entirely of dextrose, but later fructose (laevulose) is formed.