#16: Alcohol trival

Wine steeps creations of microbes!

While humans understanding food denaturing as “rotten”, a synonym of rather opposite impression, the process of fermentation initiated by microbes, has always been the sole key for any alcohol-producing works. Sugars present in foods are the prerequisite, and through anaerobic respiration, microbes, largely enzymes and certain bacteria assimilate sugars, converting which into energy, for sustaining life and reproduction. From the reaction, material released, or "excreted", include carbon dioxide and ethyl alcohol, and that pool progressively more alcoholic, taken metaphorically, or absurdly, a “septic tank”. While theories seem straightforward, in real-life brewing challenges, however, are not as laissez-faire!

“Gallant horses of eloquent tones, or fur coats costing thousands of gold, now having my kid to pawn those in exchange for fine liquor, with you all easing that misery of millennia! ” One millennium ago in ancient China, a tipsy master poet, Li Bai (701–762), made these words of vigorous momentum, exclaiming gloominess and grief in vicissitudes of life, which ever-lastingly embedded in history. The time span, however, was no match for history of alcohol consumption itself in ancient China: earliest archaeological evidence in the form of pottery containing fermented beverages had been uncovered in Henan (Central China), dated nine thousand years ago, and the deep-rooted routine is as prevailing nowadays, from wedding, birth and mourn, and alcohols of all forms are frequently encountered. But how well do we understand this tempting beverage?

Where does alcohol come from? Certainly instructing a minor out to purchase, like old Master Li did, was not quite an answer. While alcoholic beverages brewed and present themselves in countless ways and not discussed in depth, instead we dig into ins-and-outs of the essential ingredient, ethyl alcohol (= ethanol).

How efficient: While most yeasts capable of fermenting sugars, not many serves as efficiently in anaerobic respiration, and releasing satisfiable portions of ethanol.

Hoist with his own petard: When yeasts respire and bringing along ethanol as a by-product, in the pool alcoholic contents accumulate, to a certain degree of poisoning themselves, in turn hampering "productivity" and eventually self-eradicating! As such, most un-distilled alcohols have concentrations reaching a maximum below 20 percent.

Struggle against counterparts: During fermentation processes aside from specific alcohol-producing yeasts manually added, many of those pre-existing on the ingredients cannot be excluded. These “natives” are nowhere docile, but competes by releasing a toxic protein called zymocin. Strains of alcohol-producing yeasts with enhanced resistance towards zymocin are thus crucial.

Apparently, these considerations are merely several among many aspects in producing fine wines. Always expertly managed and exquisitely carved, for those admired and intoxicated. So what wizardry these liquids deliver to capture, for countless centuries, all those souls that lust after?

ADH4: something unintentional

Rather not just humans, but also our distant primate ancestors in deep time. Some 45 million years ago, those ape-like precursors of ours did had a taste of drowsiness by consuming fermented fruits, but for most alike primates, efficiently processing alcohol had not been something readily acquainted. As such foodstuff containing substantial portions of alcohol, such as fallen and fermenting fruits, was kept at a respectful distance.
This teetotaller strategy was brought to an abrupt U-turn by around ten million years from now, thanks to an unexpected emergence of a mutation at the ADH4 (alcohol dehydrogenase 4) gene. This fostered production of alcohol dehydrogenase for decomposing ethanol and enhancing the capability some forty times in certain ape-like species in comparison with yet-mutated counterparts. In hindsight, this change has been believed critical in the course of evolution in ape-like animals. While fruits in the process of maturation soften, colours increasing vivid, sugar contents soar, and for the sake of obtaining food items of better quality, our ape-like ancestors preferred foraging on the ground rather than spending good portions of time in the canopy of forests. Some, with enhanced senses targeting that sweetened and “rotten” scent, ended up had their days browsing actively on the ground surface. Aside from the sugar content, suitable portions of alcohol also perform functions such as improving food digestion, and as a mild antiseptic.

Text: Tin-Lun Wong

Illustration: Kingsley Wong

Blame the brain for drunkenness!

Two sides of a coin these are that radar sensing for tasty (rotten) fruits, and that underplot of alcohol abuse of decedents, numerous as sands in the Ganges. While some as Master Li trading good wealth for good wines, or some archaeologists and scientists attempting to unveiling mysteries in the history of folks getting inebriated, at the first place how did these formidable liquids tempered with our bodies and souls?

All comes to the deed in the world of neurotransmitters. Each of these is biochemical signals transmitted within the body, precisely coordinating all functions, from breathing, heartbeats, to emotions. A specific neurotransmitter named γ-Aminobutyric acid, or GABA for short, represses neurotransmissions leaving brains nerves at a state of relaxation, hence obstructing muscle control. Ethanol enhances influences of GABA on the brain, therefore triggers resultant tardy motions and confused speech, as well as all those hilarious deeds, where others merrily grab good popcorn.

At the meantime, ethanol also enhances release of another neurotransmitter dopamine within the reward system, which composed of the ventral area, nucleus accumbens and prefrontal cortex, yielding a satisfying emotion, all along the way of consumption. However, the Law of Diminishing Returns does set in at the dopamine-releasing mechanism, and the individual would require further alcohol to attain similar levels of satisfaction, and this vicious cycle of “getting high”, cumulatively contributes to abusive behaviors.

All in all, liquors are something twofold: for the peace of mind, for fun gatherings, or unrestrained indulgences, for savoring the moment, or deeds of indecency and disgrace. As for those rampantly abusing, it seems like one reaps what one sowed: aside from instant outrageous behavior, health withers in terms of cardiovascular and liver diseases, diabetes, osteoporosis, sexual dysfunction, and cancer.

None can possibly deny getting a drink every now and then can be enjoyable. As for anything near to that fortnightly drunkenness as legendary as another Chinese master poet Ruan Ji (210–263), who attempted to evade marriage proposals of his daughter with a pampered boy from a power-seizing family (he succeeded though), would be rather suicidal. As said.