Microbiology and Biochemistry: Difference between revisions
Created page with "The spontaneous fermentation of lambic is a complex process involving a succession of bacteria and yeasts that progresses along with the chemical changes that occur during fer..." |
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The enteric stage | The enteric stage | ||
Lambic wort arrives in the coolship at approximately yy% sugar per weight of water, along with an assortment of proteins and fatty acids and other compounds[ref]. Negligible ethanol is present prior to fermentation, nor is there much of the organic acids that will give lambic its characteristic tartness; the wort has a pH around 4.8, which is similar to the wort of other beers. Enteric bacteria, including ______, _______, and _______ are the first to gain a foothold in this environment, with significant numbers found after three to four days. The enteric bacteria primarily consume glucose, which reduces the gravity of the wort from ___ to ___ after the first three weeks. | Lambic wort arrives in the coolship at approximately yy% sugar per weight of water, along with an assortment of proteins and fatty acids and other compounds[ref]. Negligible ethanol is present prior to fermentation, nor is there much of the organic acids that will give lambic its characteristic tartness; the wort has a pH around 4.8, which is similar to the wort of other beers. Enteric bacteria, including ______, _______, and _______ are the first to gain a foothold in this environment, with significant numbers found after three to four days. The enteric bacteria primarily consume glucose, which reduces the gravity of the wort from ___ to ___ after the first three weeks. | ||
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Saccromyces dominance | Saccromyces dominance | ||
After the pH falls below ~4.5 and the alcohol content rises over ~2%, Saccromyces species take over as the dominant organisms in the wort, though Saccromyces is present in large numbers well prior to the dissapearance of the enterobacteria. Saccromyces will remain dominant until at least ___, and usually maintain a considerable presence until ____, when Brettanomyces becomes dominant. Despite Saccromyces' importance to the fermentation, its concentrations remain below 10^7 cells per mL of wort, which is considerably lower than the 10^8 cells/mL found in commercial beers [6]. | After the pH falls below ~4.5 and the alcohol content rises over ~2%, Saccromyces species take over as the dominant organisms in the wort, though Saccromyces is present in large numbers well prior to the dissapearance of the enterobacteria. Saccromyces will remain dominant until at least ___, and usually maintain a considerable presence until ____, when Brettanomyces becomes dominant. Despite Saccromyces' importance to the fermentation, its concentrations remain below 10^7 cells per mL of wort, which is considerably lower than the 10^8 cells/mL found in commercial beers [6]. | ||
As in controlled fermentation, Saccromyces is responsible for most ethanol production and attenuation in lambic. The yeasts consume all the major sugars found in lambic wort (glucose, maltose, and even maltotriose). By the end of the Saccromyces phase around __-8 months, the ethanol content of the beer stabilizes at 5-7% by volume and will remain around that value until the end of fermentation[5,7]. Attenuation after Saccromyces fermentation reaches 60-65%, which is known as the "attenuation limit" for conventional beers. | As in controlled fermentation, Saccromyces is responsible for most ethanol production and attenuation in lambic. The yeasts consume all the major sugars found in lambic wort (glucose, maltose, and even maltotriose). By the end of the Saccromyces phase around __-8 months, the ethanol content of the beer stabilizes at 5-7% by volume and will remain around that value until the end of fermentation[5,7]. Attenuation after Saccromyces fermentation reaches 60-65%, which is known as the "attenuation limit" for conventional beers. | ||
Other bacteria and yeasts also thrive during the Saccromyces phase. ____ and ____ both survive in considerable numbers alongside Saccromyces. MORE | Other bacteria and yeasts also thrive during the Saccromyces phase. ____ and ____ both survive in considerable numbers alongside Saccromyces. MORE STUFF ON OTHER ORGANISMS DURING SACC PHAZE | ||
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The Brettanomyces stage | 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 __ 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. | ||
Refermentation in the bottle | 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 ____ 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]. | ||
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Continued aging | Continued aging | ||
Eventually even the slow-fermenting Brettanomyces runs out of fermentable sugars and fermentation draws to a slow close. The beer will continue to change and evolve over time, though minimal interaction with active yeast occurs. This stage is marked by oxidation and breakdown of the more complex parts of the yeast itself [ref]. | Eventually even the slow-fermenting Brettanomyces runs out of fermentable sugars and fermentation draws to a slow close. The beer will continue to change and evolve over time, though minimal interaction with active yeast occurs. This stage is marked by oxidation and breakdown of the more complex parts of the yeast itself [ref]. | ||
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== Geographical variation == | == Geographical variation == | ||
Discussion about geographical variation of microorganims goes here. | |||
== Seasonal variation == | == Seasonal variation == | ||
Seasonal innoculation variation data goes here. | |||
== Other spontaneous fermentations == | == Other spontaneous fermentations == | ||
American Coolship Ale | American Coolship Ale | ||
Spontaneously fermented beers from the United States (and occasionally other parts of the world | |||
Spontaneously fermented beers from the United States (and occasionally other parts of the world) form a group of beers referred to as American Coolship Ales or ACAs. ACAs vary in their intended similarity to lambic, with some American producers even going so far as to label their beers "lambics", while other ACAs bear little in common with lambic besides spontaneous fermentation. Due to the geographical separation between the United States and Belgium and the large variations in yeast and bacteria genetics between these different populations, even an ACA wort carefully prepared to be very similar to that of lambic will yeild notably different results after fermentation, even if the overall experience of the two styles of beer is similar [2,3,8]. | |||
Other spontaneous fermentations? Chicha? Cheese? etc? | |||