Microbiology and Biochemistry: Difference between revisions

Line 23:

Enteric bacteria are responsible for the production of [[acetic acid]], and the pH of the wort falls from around 5 to 4.5 in the first week of fermentation. The 40 to 120 mg/L acetic acid found in the wort after the first week is very close to the amount found in the final product.<ref name=Oevelen77 >D. Van Oevelen, M. Spaepen, P. Timmermans and H. Verachtert, [http://onlinelibrary.wiley.com/doi/10.1002/j.2050-0416.1977.tb03825.x/abstract| MICROBIOLOGICAL ASPECTS OF SPONTANEOUS WORT FERMENTATION IN THE PRODUCTION OF LAMBIC AND GUEUZE], 1977</ref>

<ref name=sour>John Edwards and Adam DiCaprio. [http://www.process-nmr.com/pdfs/Edwards%20-%20SMASH%202014%20-%20MNova%20Users%20Meeting%20-%209-7-14.pdf|When Beer Goes Sour: An NMR Investigation], Mestrelab

MNova Users Meeting, SMASH – Atlanta, GA, September 7, 2014</ref> Significant changes to the concentration of acetic acid should not occur until the ethanol has a chance to oxidize in aging in the bottle over many years or even decades [6]. The pellicle that forms on the top of the wort forms around ___ days, and ~~is likely~~ the product of acetobacteria during the enteric phase [9].

MNova Users Meeting, SMASH – Atlanta, GA, September 7, 2014</ref> Significant changes to the concentration of acetic acid should not occur until the ethanol has a chance to oxidize in aging in the bottle over many years or even decades [6]. The pellicle that forms on the top of the wort forms around ___ days, and may be the product of acetobacteria during the enteric phase,[9] though most other sources inidcate that the pellicle is the result of Brettanomyces (with Pichia and Candida).<ref name="Guinard">Jean-Xavier Guinard, [[Books#Classic Beer Styles: Lambic|Classic Beer Styles: Lambic]], 1990</ref>

Low pH (below ~4.5) and an ethanol concentration higher than ~2% by volume is a hostile environment to the enterobacteria, and Saccromyces species are able to dominate in the wort once these conditions occur around 30-60 days into fermentation.

Line 45:

The Brettanomyces stage

Brettanomyces inherits the role of most prominant yeast genera from Saccromyces around __ 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 saccromyces alone, as brettanomyces is able to metabolise sugars that saccromyces cannot.

Brettanomyces inherits the role of most prominant yeast genera from Saccromyces 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 saccromyces alone, as brettanomyces is able to metabolise sugars that saccromyces 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>

Refermentation in the bottle

Gueuze and other lambic bottled with either some residual sugar left unfermented at the time of bottling or added priming sugars will undergo significant fermentation in the bottle, though all unpasteurized lambic will continue to ferment to some degree there. For lambic bottled after about ~~____~~ months without additional sugar, the fermentation in the bottle progresses much as an extension of the Brettanomyces stage of fermentation and negligible carbon dioxide and ethanol production occurrs, leaving most of this lambic still. For lambic bottled younger and those with additional fermentable sugars added at bottling, considerable fermentation by saccromyces occurs in the bottle, causing marked increases in ethanol and the production of carbon dioxide, leading to a carbonated product [ref].

Gueuze and other lambic bottled with either some residual sugar left unfermented at the time of bottling or added priming sugars will undergo significant fermentation in the bottle, though all unpasteurized lambic will continue to ferment to some degree there. For lambic bottled after about 8 months without additional sugar, the fermentation in the bottle progresses much as an extension of the Brettanomyces stage of fermentation and negligible carbon dioxide and ethanol production occurrs, leaving most of this lambic still. For lambic bottled younger and those with additional fermentable sugars added at bottling, considerable fermentation by saccromyces occurs in the bottle, causing marked increases in ethanol and the production of carbon dioxide, leading to a carbonated product [ref].

The reactivation of saccromyces fermentation at the addition of additional sugar indicates that the dominance of brettanomyces is brought about by brettanomyces ability to ferment sugars that saccromyces cannot. Once saccromyces has consumed ~~all~~ the available ______ and ______ in the wort, it goes dormant, though does not die completely, and brettanomycs is free to assume the role of primary yeast in the wort. Upon the re-introduction of _____ and _____, the faster-growing saccromyces once again flourishes, until the again the fermentable sugar is consumed and brettanomyces and its other associated yeasts can once again resume the slow procress of the final fermentation.

The reactivation of saccromyces fermentation at the addition of additional sugar indicates that the dominance of brettanomyces is brought about by brettanomyces ability to ferment sugars that saccromyces cannot. Once saccromyces has consumed most of the available ______ and ______ in the wort, it goes dormant, though does not die completely, and brettanomycs is free to assume the role of primary yeast in the wort. Upon the re-introduction of _____ and _____, the faster-growing saccromyces once again flourishes, until the again the fermentable sugar is consumed and brettanomyces and its other associated yeasts can once again resume the slow procress of the final fermentation.

Continued aging

@@ Line 23: / Line 23: @@
 Enteric bacteria are responsible for the production of [[acetic acid]], and the pH of the wort falls from around 5 to 4.5 in the first week of fermentation. The 40 to 120 mg/L acetic acid found in the wort after the first week is very close to the amount found in the final product.<ref name=Oevelen77 >D. Van Oevelen, M. Spaepen, P. Timmermans and H. Verachtert, [http://onlinelibrary.wiley.com/doi/10.1002/j.2050-0416.1977.tb03825.x/abstract| MICROBIOLOGICAL ASPECTS OF SPONTANEOUS WORT FERMENTATION IN THE PRODUCTION OF LAMBIC AND GUEUZE], 1977</ref>
 <ref name=sour>John Edwards and Adam DiCaprio. [http://www.process-nmr.com/pdfs/Edwards%20-%20SMASH%202014%20-%20MNova%20Users%20Meeting%20-%209-7-14.pdf|When Beer Goes Sour: An NMR Investigation], Mestrelab
-MNova Users Meeting, SMASH – Atlanta, GA, September 7, 2014</ref> Significant changes to the concentration of acetic acid should not occur until the ethanol has a chance to oxidize in aging in the bottle over many years or even decades [6]. The pellicle that forms on the top of the wort forms around ___ days, and is likely the product of acetobacteria during the enteric phase [9].
+MNova Users Meeting, SMASH – Atlanta, GA, September 7, 2014</ref> Significant changes to the concentration of acetic acid should not occur until the ethanol has a chance to oxidize in aging in the bottle over many years or even decades [6]. The pellicle that forms on the top of the wort forms around ___ days, and may be the product of acetobacteria during the enteric phase,[9] though most other sources inidcate that the pellicle is the result of Brettanomyces (with Pichia and Candida).<ref name="Guinard">Jean-Xavier Guinard, [[Books#Classic Beer Styles: Lambic|Classic Beer Styles: Lambic]], 1990</ref>
 Low pH (below ~4.5) and an ethanol concentration higher than ~2% by volume is a hostile environment to the enterobacteria, and Saccromyces species are able to dominate in the wort once these conditions occur around 30-60 days into fermentation.
@@ Line 45: / Line 45: @@
 The Brettanomyces stage
-Brettanomyces inherits the role of most prominant yeast genera from Saccromyces around __ 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 saccromyces alone, as brettanomyces is able to metabolise sugars that saccromyces cannot.
+Brettanomyces inherits the role of most prominant yeast genera from Saccromyces 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 saccromyces alone, as brettanomyces is able to metabolise sugars that saccromyces 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>
 Refermentation in the bottle
-Gueuze and other lambic bottled with either some residual sugar left unfermented at the time of bottling or added priming sugars will undergo significant fermentation in the bottle, though all unpasteurized lambic will continue to ferment to some degree there. For lambic bottled after about ____ months without additional sugar, the fermentation in the bottle progresses much as an extension of the Brettanomyces stage of fermentation and negligible carbon dioxide and ethanol production occurrs, leaving most of this lambic still. For lambic bottled younger and those with additional fermentable sugars added at bottling, considerable fermentation by saccromyces occurs in the bottle, causing marked increases in ethanol and the production of carbon dioxide, leading to a carbonated product [ref].
+Gueuze and other lambic bottled with either some residual sugar left unfermented at the time of bottling or added priming sugars will undergo significant fermentation in the bottle, though all unpasteurized lambic will continue to ferment to some degree there. For lambic bottled after about 8 months without additional sugar, the fermentation in the bottle progresses much as an extension of the Brettanomyces stage of fermentation and negligible carbon dioxide and ethanol production occurrs, leaving most of this lambic still. For lambic bottled younger and those with additional fermentable sugars added at bottling, considerable fermentation by saccromyces occurs in the bottle, causing marked increases in ethanol and the production of carbon dioxide, leading to a carbonated product [ref].
-The reactivation of saccromyces fermentation at the addition of additional sugar indicates that the dominance of brettanomyces is brought about by brettanomyces ability to ferment sugars that saccromyces cannot. Once saccromyces has consumed all the available ______ and ______ in the wort, it goes dormant, though does not die completely, and brettanomycs is free to assume the role of primary yeast in the wort. Upon the re-introduction of _____ and _____, the faster-growing saccromyces once again flourishes, until the again the fermentable sugar is consumed and brettanomyces and its other associated yeasts can once again resume the slow procress of the final fermentation.
+The reactivation of saccromyces fermentation at the addition of additional sugar indicates that the dominance of brettanomyces is brought about by brettanomyces ability to ferment sugars that saccromyces cannot. Once saccromyces has consumed most of the available ______ and ______ in the wort, it goes dormant, though does not die completely, and brettanomycs is free to assume the role of primary yeast in the wort. Upon the re-introduction of _____ and _____, the faster-growing saccromyces once again flourishes, until the again the fermentable sugar is consumed and brettanomyces and its other associated yeasts can once again resume the slow procress of the final fermentation.
 Continued aging