Search results
Results from the WOW.Com Content Network
Lager yeast normally ferments at a temperature of approximately 5 °C (41 °F) or 278 k, where Saccharomyces cerevisiae becomes dormant. A variant yeast known as Saccharomyces cerevisiae var. diastaticus is a beer spoiler which can cause secondary fermentations in packaged products. [68]
Saccharomyces cerevisiae, the yeast commonly used as baker's yeast. Gradation marks are 1 μm apart.. Baker yeast is the common name for the strains of yeast commonly used in baking bread and other bakery products, serving as a leavening agent which causes the bread to rise (expand and become lighter and softer) by converting the fermentable sugars present in the dough into carbon dioxide and ...
The most common yeast associated with winemaking is Saccharomyces cerevisiae which has been favored due to its predictable and vigorous fermentation capabilities, tolerance of relatively high levels of alcohol and sulfur dioxide as well as its ability to thrive in normal wine pH between 2.8 and 4.
In the paper "Mémoire sur la fermentation alcoolique," Pasteur proved that alcoholic fermentation was conducted by living yeasts and not by a chemical catalyst. [14] [20] By the late 18th century two yeast strains used in brewing had been identified: Saccharomyces cerevisiae (top-fermenting yeast) and S. pastorianus (bottom-fermenting yeast).
This temperature would be low for most kinds of fermentation, but is beneficial for cider, as it leads to slower fermentation with less loss of delicate aromas. Fermentation can occur due to natural yeasts that are present in the must; alternately, some cider makers add cultivated strains of cider yeast, such as Saccharomyces bayanus .
Yeast need a reliable source of nitrogen in forms that they can assimilate in order to successfully complete fermentation. Yeast assimilable nitrogen or YAN is the combination of free amino nitrogen (FAN), ammonia (NH 3) and ammonium (NH 4 +) that is available for a yeast, e.g. the wine yeast Saccharomyces cerevisiae, to use during fermentation.
For example, the important industrial yeast strain Saccharomyces pastorianus is an interspecies hybrid of S. cerevisiae and the cold tolerant S. eubayanus. [15] This hybrid is commonly used in lager-brewing, which requires slow, low temperature fermentation. [15]
Saccharomyces bayanus is a yeast of the genus Saccharomyces, and is used in winemaking and cider fermentation, and to make distilled beverages. Saccharomyces bayanus, like Saccharomyces pastorianus, is now accepted to be the result of multiple hybridisation events between three pure species, Saccharomyces uvarum, Saccharomyces cerevisiae and Saccharomyces eubayanus.