Microbiology and Biochemistry: Difference between revisions

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==Pediococcus dominance==

After the changing environment of the wort ends the growth of the enteric bacteria around ____ days, bacteria of the pediococcus come to dominate the bacterial flora. Lactobacillus can also be found in the wort in large numbers at this time, and both genuses are responsible for most of the [[Lactic acid]] in Lambic. Collectively these bacteria are known as the lactic acid bacteria.

-- ~~[[Lactic acid]~~]

The lactic acid bacteria increase in number until around month 7, achieving concentrations of ____ cells/mL wort, which is thought to coincide with the onset of summer and warmer temperatures. With this in mind, it is thought that the increase in lactic acid bacteria be delayed or hastened by decreasing or increasing the storage temperatures, respectively.<ref name=AWAs> Nicholas A. Bokulich, Charles W. Bamforth, David A. Mills. [http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0035507 | Brewhouse-Resident Microbiota Are Responsible for Multi-Stage Fermentation of American Coolship Ale], PLoS One, 7(4), 2012</ref>

Interestingly, lactic acid bacteria have been implicated in racemizing amino acids in beer, causing Lambic (and other beers which make use of lactic acid bacteria such as Berliner Wiesse) to have a high percentage of right-handed amino acid stereoisomers relative to both their starting materials and other beers.<ref name=Erbe >T. Erbe and H. Brückner, [http://www.sciencedirect.com/science/article/pii/S0021967300002557|Chromatographic determination of amino acid enantiomers in beers and raw materials used for their manufacture], 2000</ref>

@@ Line 36: / Line 36: @@
 ==Pediococcus dominance==
+After the changing environment of the wort ends the growth of the enteric bacteria around ____ days, bacteria of the pediococcus come to dominate the bacterial flora. Lactobacillus can also be found in the wort in large numbers at this time, and both genuses are responsible for most of the [[Lactic acid]] in Lambic. Collectively these bacteria are known as the lactic acid bacteria.
--- [[Lactic acid]]
+The lactic acid bacteria increase in number until around month 7, achieving concentrations of ____ cells/mL wort, which is thought to coincide with the onset of summer and warmer temperatures. With this in mind, it is thought that the increase in lactic acid bacteria be delayed or hastened by decreasing or increasing the storage temperatures, respectively.<ref name=AWAs> Nicholas A. Bokulich, Charles W. Bamforth, David A. Mills. [http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0035507 | Brewhouse-Resident Microbiota Are Responsible for Multi-Stage Fermentation of American Coolship Ale], PLoS One, 7(4), 2012</ref>
 Interestingly, lactic acid bacteria have been implicated in racemizing amino acids in beer, causing Lambic (and other beers which make use of lactic acid bacteria such as Berliner Wiesse) to have a high percentage of right-handed amino acid stereoisomers relative to both their starting materials and other beers.<ref name=Erbe >T. Erbe and H. Brückner, [http://www.sciencedirect.com/science/article/pii/S0021967300002557|Chromatographic determination of amino acid enantiomers in beers and raw materials used for their manufacture], 2000</ref>