615
edits
Changes
Hops
,starting antimicrobial
'''(In progress)'''
Hops are a dioecious climbing bine, meaning that they have separate male and female plants. The female cones are used in beer for flavor as well as for antimicrobial properties. Need info on hops and how they pertain to alternate brewing methods, yeasts, and bacterium
Potential references (https://www.facebook.com/groups/MilkTheFunk/permalink/1190513557643523/?qa_ref=qd&comment_id=1195663997128479&comment_tracking=%7B%22tn%22%3A%22R%22%7D):
# https://www.facebook.com/groups/MilkTheFunk/permalink/1228610483833830/
# https://www.facebook.com/groups/MilkTheFunk/permalink/1234538973240981/
==Antimicrobial Properties==
Hops are known to have antimicrobial properties against gram positive bacteria. This includes bacteria which can be present in beer both as spoilage organisms and as intentionally added in sour and mixed fermentation beer such as ''[[Lactobacillus]]'' and ''[[Pediococcus]]''. Certain other bacteria found in beer such as ''Acetobacteraciae'' are gram negative and are not susceptible to the antimicrobial properties of hops. Certain Gram posotive bacteria are known to be more resistant to the antimicrobial effects of hops. Multiple mechanisms have been proposed to explain why hops are antimicrobially active.
[http://www.sciencedirect.com/science/article/pii/S0168160503001533 Sakamoto and Konings (2003)] attributed the antimicrobial effects the iso-α-acids acting as ionophores to cause leaking of ions across cell membranes. The protonated iso-α-acid (the form of the acid with an associated H+ ion, an H+ ion is a proton) is the antimicrobially active form. This means that for a beer with a given iso-α-acid concentration, the antimicrobial effects will be stronger at lower pH values because a greater percentage of the acid will be protonated. The protonated iso-α-acids are antimicrobially active by crossing into the cell and dissociating (releasing the H+ ion from the iso-α-acid), therefore disrupting the cellular proton gradient which is necessary for cells to function, before crossing back out of the cell. Cells with a resistance to hop bitter acids are better able to eject undissociated iso-α-acids from the cell and therefore preserve their proton gradients. This resistance to hop antimicrobial activities through iso-α-acids appears to be stable within bacteria with the trait, and the mechanism to expel iso-α-acids appears to be specific toward this type of compound rather than by a more general antimicrobial resistance mechanism such as multi-drug resistant bacteria possess<ref name="Sakamoto and Konings, 2003"/>.
(in progress)
Other mechanisms including oxidative stress and Mn.
==Aged Hops==
==Glycosides and ''Brettanomyces''==
Hops contain glycosides, which are flavor compounds that are bound to a sugar molecule. In their bound form, glycosides are flavorless. Enzymatic activity from some strains of ''Brettanomyces'' can release these bound compounds and release their flavor and aromatic potential. See the [[Brettanomyces#Glycosides_and_Beta-Glucosidase_Activity|''Brettanomyces'']] page for details.
==Techniques==