Microbiology and Biochemistry: Difference between revisions

Line 46:

Brettanomyces inherits the role of most prominant yeast genera from Saccharomyces around 8 months, and continues consuming sugar in the wort. Final attenuation can reach over 80% in lambic through the continued action of Brettanomyces, which is often referred to as "overattenuation" or "superattenuation". This is greater than is usually possible with Saccharomyces alone, as brettanomyces is able to metabolise sugars that Saccharomyces cannot, generally known as "dextrins".

Brettanomyces has been implicated in producing most of the aroma compounds in Lambic.<ref name="Guinard">Jean-Xavier Guinard, [[Books#Classic Beer Styles: Lambic|Classic Beer Styles: Lambic]], 1990</ref> Sensory-significant quantities of ethyl acetate and ethyl lactate form at this time from ethanol entering into an ester bond with acetic and lactic acid, respectively. The esterization process is greatly helped by the enzyme esterase provided by Brettanomyces. However, the enzymatic esterization is highly reversible and esters found in high concentrations in the lambic prior to the presence of the esterase will achieve a lower equilibrium. This is the case with iso-amyl acetate, which is produced by Saccharomyces and is a characteristic odor compound in most other beers.[ref] Tetrahydropyridines (THPs) produced by Brettanomyces give Lambic its horse-like aroma, though the concentration and thus smell of THPs is variable.[ref, Heresztyn, 1986]

Brettanomyces has been implicated in producing most of the aroma compounds in Lambic.<ref name="Guinard">Jean-Xavier Guinard, [[Books#Classic Beer Styles: Lambic|Classic Beer Styles: Lambic]], 1990</ref> Sensory-significant quantities of ethyl acetate and ethyl lactate form at this time from ethanol entering into an ester bond with [[Acetic acid|acetic]] and [[lactic acid]], respectively. The esterization process is greatly helped by the enzyme esterase provided by Brettanomyces. However, the enzymatic esterization is highly reversible and esters found in high concentrations in the lambic prior to the presence of the esterase will achieve a lower equilibrium. This is the case with iso-amyl acetate, which is produced by Saccharomyces and is a characteristic odor compound in most other beers.[ref] Tetrahydropyridines (THPs) produced by Brettanomyces give Lambic its horse-like aroma, though the concentration and thus smell of THPs is variable.[ref, Heresztyn, 1986]

=Refermentation in the bottle=

@@ Line 46: / Line 46: @@
 Brettanomyces inherits the role of most prominant yeast genera from Saccharomyces around 8 months, and continues consuming sugar in the wort. Final attenuation can reach over 80% in lambic through the continued action of Brettanomyces, which is often referred to as "overattenuation" or "superattenuation". This is greater than is usually possible with Saccharomyces alone, as brettanomyces is able to metabolise sugars that Saccharomyces cannot, generally known as "dextrins".
-Brettanomyces has been implicated in producing most of the aroma compounds in Lambic.<ref name="Guinard">Jean-Xavier Guinard, [[Books#Classic Beer Styles: Lambic|Classic Beer Styles: Lambic]], 1990</ref> Sensory-significant quantities of ethyl acetate and ethyl lactate form at this time from ethanol entering into an ester bond with acetic and lactic acid, respectively. The esterization process is greatly helped by the enzyme esterase provided by Brettanomyces. However, the enzymatic esterization is highly reversible and esters found in high concentrations in the lambic prior to the presence of the esterase will achieve a lower equilibrium. This is the case with iso-amyl acetate, which is produced by Saccharomyces and is a characteristic odor compound in most other beers.[ref] Tetrahydropyridines (THPs) produced by Brettanomyces give Lambic its horse-like aroma, though the concentration and thus smell of THPs is variable.[ref, Heresztyn, 1986]
+Brettanomyces has been implicated in producing most of the aroma compounds in Lambic.<ref name="Guinard">Jean-Xavier Guinard, [[Books#Classic Beer Styles: Lambic|Classic Beer Styles: Lambic]], 1990</ref> Sensory-significant quantities of ethyl acetate and ethyl lactate form at this time from ethanol entering into an ester bond with [[Acetic acid|acetic]] and [[lactic acid]], respectively. The esterization process is greatly helped by the enzyme esterase provided by Brettanomyces. However, the enzymatic esterization is highly reversible and esters found in high concentrations in the lambic prior to the presence of the esterase will achieve a lower equilibrium. This is the case with iso-amyl acetate, which is produced by Saccharomyces and is a characteristic odor compound in most other beers.[ref] Tetrahydropyridines (THPs) produced by Brettanomyces give Lambic its horse-like aroma, though the concentration and thus smell of THPs is variable.[ref, Heresztyn, 1986]
 =Refermentation in the bottle=