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.

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

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].

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 ~~____~~ days into fermentation.

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.

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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.
-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
+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].
-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 ____ days into fermentation.
+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.