Microbiology and Biochemistry: Difference between revisions
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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 Enterobacter hormaechei, E. kobei, Klebsiella pneumoniae, and Escherichia coli, 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 Enterobacter hormaechei, E. kobei, Klebsiella pneumoniae, and Escherichia coli, 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. | ||
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[5,8] <ref name= | 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[5,8] <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 is likely the product of acetobacteria during the enteric phase [9]. | ||
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American Coolship Ale | American Coolship Ale | ||
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 <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>. 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 <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> <ref name= | 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 <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>. 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 <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> <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> [2,3,8]. | MNova Users Meeting, SMASH – Atlanta, GA, September 7, 2014</ref> [2,3,8]. | ||