Fusel alcohols verða til við gerjun, við hærra hitastig, lítið pH gildi og þegar lítið nítrógen takmarkar getu gersins til að gerja samkvæmt wikipedia.
A by-product of carbohydrate fermentation to produce ethyl alc. The material varies widely in composition, depending on the fermentation raw material used, but contains chiefly isopentyl alcohol and 2-methyl-1-butanol as well as isobutyl alcohol(20%), n-propyl alcohol(3-5%), and small amounts of other alcohols, esters and aldehydes. Described as an oily liq with a disagreeable odor; 60% boils at 122-138°. Amyl alcohol (commercial) obtained by chemical treatment and refining of fusel oil contains about 85% isopentyl alcohol and 15% 2-methyl-1-butanol. Ref: Industrial Chemicals, W.L. Faith et al.
http://en.wikipedia.org/wiki/Fusel_alcohols" onclick="window.open(this.href);return false;
Þessi alkahól hafa 2 karbon mólikjúl og gufa líka upp við hærra hitastig þannig að ef einhver myndi vera að eima þá væri þetta það síðasta sem kæmi úr tækinu og er kallað "tails" eða hali.
Ég hef verið að lesa frekar mikið af efnafræði undanfarið, mæli með basic chemistry eftir Timberlake & Timberlake, kostar einhvern 11 þús kall í bókasölu stúdenta en ef fólk hefur áhuga á svona...
Ég held að gernæring ætti að hjálpa næst.
Recent studies have shown that the balance between the oxidation and the reduction of the fusel aldehydes depends strongly on cultivation conditions. In aerobic glucose-limited chemostat cultures grown with various amino acids (leucine, methionine, and phenylalanine) as sole nitrogen sources, the amino acids are converted predominantly to fusel acids and only very low concentrations of fusel alcohols are formed (2, 63, 64). In such cultures, the biomass yield on glucose is 40% lower than that of cultures grown on other nitrogen sources, thus implying that a large energy drain is associated with the formation of fusel acids (2). Given the relatively high levels of hydrophobicity of these weak organic acids, it seems probable that ATP dissipation occurs through classical (29, 49) weak organic acid uncoupling of the plasma membrane pH gradient.
A key role of the cellular redox status in determining the ratio of fusel acid to fusel alcohol production is consistent with the observations discussed above. In glucose-grown batch cultures of S. cerevisiae, growth is predominantly fermentative, and when phenylalanine is the sole nitrogen source, it is converted into a mixture of 90% fusel alcohol (phenylethanol) and less than 10% fusel acid (phenylacetate). Furthermore, fully fermentative dissimilation of glucose under anaerobic conditions (in batch or chemostat cultures) results in the almost complete conversion of phenylalanine to phenylethanol (63, 64).
http://aem.asm.org/cgi/content/full/74/ ... d=18281432" onclick="window.open(this.href);return false;