ethanol 3d molecular diagram   T H Å N Ø £  
C2H5OH   ƒlammable, colorless
chemical compound best known as
alcohol; found in thermometers
& alcoholic beverages
    & links
After use of fire, fermentation of sugar into ethanol is perhaps the earliest organic reaction known to humanity. In modern times ethanol intended for industrial use has also been produced from petroleum refining byproducts.
Ethanol has a long history as fuel, incl for internal combustion engines. Ethanol is a versatile solvent.

Dried residues on 9000-year-old pottery found in China imply use of alcoholic beverages even among Neolithic people.
ethanol molecular space model shopping list
CARDINAL MENDOZA BRANDY Spanish brandy was originally made for the exclusive use of the Sanchez Romate family and close friends, but it was so outstanding that an immediate demand for it occurred, now over 200 years later it is still made according to the same family recipe, with the brandy aged for an average of 15 years. Sale $29.99 Was $49.99 750ml

Q.   What the hell is port ?         A.   is juiced up, jacked up wine.
Generally, wine is fruit juice left to sit a year after adding water, sugar, and yeast, which eats the sugar to make ethanol and CO2, the latter vented naturally through a water barrier air seal.
Any of these 4 things can be changed, added to with other steps or individually eliminated altogether.

To make port, brandy or other distilled ethanol is added to wine after the yeast is half done eating all the sugar. Brandy kills the yeast.
Brandy is wine lightly boiled in a still to reduce water in the wine in order to concentrate the ethanol.

Port is wine juiced up with liquor to jack up the fermentation, result being stronger and sweeter.
Aging in wood is nearly always a hallmark of merit, usually codified as a vintage.

The wine lake refers to the continuing surplus of wine over demand (glut) produced in the European Union. A major contributor to that glut is the Languedoc-Roussillon, which produces over one-third of the grapes grown in France.
For the past several vintages, European countries produced corresponding to 1.7 billion more bottles of wine than they sell. Hundreds of millions of bottles of wine are turned into industrial alcohol every year, a practice that is sometimes described as "emergency distillation".
Carignan, along with Aramon, is responsible for France's wine lake. Upon Algeria's independence in 1962, French supply of Carignan wine was cut off; growers in Southern France planted the vine. Its 1988 high point made it France's most widely planted grape. It's almost non-existent in its ancestral home of Aragon.
Carignan is popular for its ability to produce very large yields in the range of 11 tons/acre. Aramon can reach levels over 16 tons/acre.
    fruit   other than grapes
    et al,, esp. pear
When certain species of yeast, most importantly, Saccharomyces cerevisiae, metabolize sugar in the absence of oxygen, they produce ethanol and carbon dioxide. The process of culturing yeast under conditions to produce alcohol is called brewing.
Ethanol's toxicity to yeast limits the ethanol concentration obtainable by brewing. The most ethanol-tolerant strains of yeast can survive up to approximately 15% ethanol by volume.

Fermentation process must exclude oxygen. If oxygen is present, yeast undergo aerobic respiration which produces carbon dioxide and water rather than ethanol.
  [ Use a waterlock ]

In order to produce ethanol from starchy materials such as cereal grains, the starch must first be converted into sugars. In brewing beer, this has traditionally been accomplished by allowing the grain to germinate, or malt, which produces the enzyme, amylase.
When the malted grain is mashed, the amylase converts the remaining starches into sugars.

For fuel ethanol, hydrolysis of starch into glucose can be accomplished more rapidly by treatment with dilute sulfuric acid, fungally produced amylase, or some combination of the two.

Fermented beverages are classified by food from which fermented, determinng beer from cereal grains or other starchy materials, wines and ciders from fruit juices, and meads from honey.
Distilling fermented beverages yields whiskeys from grains; brandies from fruit, and rum from molasses or sugarcane juice. Vodka and neutral grain spirits can be distilled from any fermented material, grain or potatoes most common, and are so thoroughly distilled that no tastes from the particular starting material remain.

Numerous spirits and liqueurs are prepared by infusing flavors from fruits, herbs, and spices into distilled spirits. Gin, which is created by infusing juniper berries into a neutral grain alcohol.

In a few beverages, ethanol is concentrated by means other than distillation. Applejack is traditionally made by freeze distillation, by which water is frozen out of fermented apple cider, leaving a more ethanol-rich liquid behind. Eisbier (more commonly, eisbock) is also freeze-distilled, with beer as the base beverage.
Fortified wines are prepared by adding brandy or some other distilled spirit to partially-fermented wine. This kills the yeast and conserves some of the sugar in grape juice; such beverages are not only more ethanol-rich, but are often sweeter than other wines.

Alcoholic beverages are used in cooking, not only for their inherent flavors, but also because the alcohol dissolves hydrophobic flavor compounds which water cannot.

  Isolation as a relatively pure compound was first achieved by Muslim chemists who developed the art of distillation during the Abbasid caliphate. Al-Kindi (801-873) unambiguously described the distillation of wine.
Absolute ethanol was obtained in 1796 by Johann Tobias Lowitz by filtering distilled ethanol through charcoal.

Arrack refers to strong spirits distilled mainly in South and South East Asia from fermented fruits, grains, sugarcane, or the sap of coconuts or other palm trees.
Milky coconut sap is taken from the flowers of palm trees before they bloom. Fermenting quickly to become a mildly alcoholic drink called "toddy" or "palm wine" ("tuba" in Tagalog), it's distilled in vats made from wood, usually halmilla or teak, to produce a taste usually described between whiskey and rum.

Originally from South India, where the toddy is called kallu, today coconut arrack is mainly produced in Sri Lanka. It is generally distilled to between 33% and 50% alcohol by volume. In Sri Lanka, Arrack is the most popular local alcoholic beverage. Most of the less expensive brands are a blend of coconut Arrack and neutral spirits. Some brands are

  • V.S.O.A. ("Very Special Old Arrack")
  • Old Reserve
  • Extra Special
  • Double Distilled
Batavia Arrack is the "rum" of Indonesia, distilled from sugar cane in a type of still influenced by the Chinese, who brought the distillation process to Indonesia. Local fermented red rice is combined with local yeast to give a unique flavour and smell at approx. 70% abv, often a blend of different original parcels.

Absinthe’s mind-altering mystery solved   Proof positive: High alcohol content responsible for psychedelic effects 4.29.08   Live Science

An analysis of century-old bottles of absinthe, kind once quaffed by van Gogh and Picasso to enhance their creativity, may end the controversy over what ingredient caused the green liqueur's supposed mind-altering effects. The culprit seems plain and simple: The century-old absinthe contained about 70 percent alcohol, 140-proof. In comparison, most gins, vodkas and whiskeys are 80- to 100-proof.
In recent years, the psychedelic nature of absinthe has been hotly debated. Absinthe was notorious among 19th-century and early 20th-century bohemian artists as "the Green Fairy" that expanded the mind. After it became infamous for madness and toxic side effects among drinkers, it was widely banned.

The modern scientific consensus is that absinthe's reputation could simply be traced back to alcoholism, or perhaps toxic compounds that leaked in during faulty distillation. Still, others have pointed at a chemical named thujone in wormwood, one of the herbs used to prepare absinthe and the one that gives the drink its green color.
Thujone was blamed for "absinthe madness" and "absinthism," a collection of symptoms including hallucinations, facial tics, numbness and dementia. Prior studies suggested that absinthe had only trace levels of thujone. But critics claimed that absinthe made before it got banned in France in 1915 had much higher levels of thujone than modern absinthe produced since 1988, when the European Union lifted the ban on making absinthe.

"Today it seems a substantial minority of consumers want these myths to be true, even if there is no empirical evidence that they are," said Chemical and Veterinary Investigation Laboratory chemist Dirk Lachenmeier in Karlsruhe, Germany.
Lachenmeier and his colleagues analyzed 13 samples of absinthe from old, sealed bottles in France, Switzerland, Italy, Spain, the Netherlands and the United States dated back to the early 1900s before the ban. After uncorking the bottles, they found relatively small concentrations of thujone in that absinthe, about the same as those in modern varieties.

Laboratory tests found no other compound that could explain absinthe's effects.
"All things considered, nothing besides ethanol was found in the absinthes that was able to explain the syndrome of absinthism," Lachenmeier said. The scientists are set to detail their findings in the May 14 issue of the Journal of Agricultural and Food Chemistry.

Pure ethanol and alcoholic beverages are heavily taxed. Ethanol has many applications that do not involve human consumption. To relieve the tax burden on these applications, most jurisdictions waive the tax when agents have been added to the ethanol to render it unfit for human consumption.
These include bittering agents such as denatonium benzoate aka "Bitrex" or toxins such as methanol. Ethanol in this form is known generally as denatured alcohol; when methanol is used, it may be referred to as methylated spirits ("Meths") or "surgical spirits"..

The largest single use of ethanol is as a motor
fuel and fuel additive. The largest national fuel ethanol industries exist in Brazil; gasoline sold in Brazil contains at least 20% ethanol and anhydrous ethanol is also used as fuel.
Flex-fuel engines in Brazil are able to work with all ethanol, all gasoline, or any mixture of both. In the US flex-fuel vehicles can run on 0% to 85% ethanol (15% gasoline) since higher ethanol blends are not yet allowed.

Ethanol served as lamp fuel in the United States as early as 1840, although taxes levied during the Civil War on industrial alcohol rendered the practice uneconomical. The tax was not repealed until 1906
1908 Ford Model T automobiles could be adapted to run on ethanol. With the advent of Prohibition in 1920 though, sellers of ethanol fuel were accused of being allies of moonshiners, and ethanol fuel once again faded from the public eye. The recent rise in oil prices has spurred renewed interest.

100% pure ethanol is not approved as a motor vehicle fuel in the US, even though compared to gasoline, ethanol cuts poisonous gas emissions (carbon monoxide, nitrous oxides, sulfur dioxide) and produces fewer greenhouse gases.
Added to gasoline, ethanol also reduces ground-level ozone formation by lowering volatile organic compound and hydrocarbon emissions, decreasing carcinogenic benzene, and butadiene, emissions, and particulate matter emissions from gasoline combustion.

Since 90% of US crude oil reserves have been consumed, the US must import crude oil to meet energy demand. Substituting ethanol for gasoline would substantially reduce the foreign trade deficit, which is aggravated by crude oil and gasoline imports.
U.S. fuel ethanol industry is based largely on maize. Ethanol produced from corn has a number of critics who suggest that it is primarily just recycled fossil fuels because of the energy required to grow the grain and convert it into ethanol. controversial subsidies in the past have included more than $10 billion to Archer-Daniels-Midland since 1980. Recent articles have also blamed subsidized ethanol production for the nearly 200% increase in milk prices since 2004.

It has been estimated that "if every bushel of U.S. corn, wheat, rice and soybean were used to produce ethanol, it would only cover about 4% of U.S. energy needs on a net basis." A 2.7.08 AP article stated, "The widespread use of ethanol from corn could result in nearly twice the greenhouse gas emissions as the gasoline it would replace because of expected land-use changes".
As ethanol is more widely used, changing irrigation practices could greatly increase pressure on water resources. In October 2007, 28 environmental groups decried the Renewable Fuels Standard (RFS), a legislative effort intended to increase ethanol production, and said that the measure will A closed-loop ethanol plant attempts to address this criticism with the energy for distillation from fermented manure, produced from cattle that have been fed the by-products from the distillation. Leftover manure is then used to fertilize the soil used to grow the grain. Such a process is expected to have a much lower fossil fuel requirement.
Though in an early stage of research, there is some development of alternative production methods that use feed stocks such as municipal waste or recycled products, rice hulls, sugarcane bagasse, small diameter trees, wood chips, and switchgrass. Recent research suggests that cellulosic crops such as switchgrass provide a much better net energy production, producing over five times as much energy as the total used to produce the crop and convert it to fuel.

Brazil supports this population of ethanol-burning automobiles with large national infrastructure that produces ethanol from domestically grown sugar cane. Sugar cane not only has a greater concentration of sucrose than corn (by about 30%), but is also much easier to extract. The bagasse generated by the process is not wasted, but is utilized in power plants as a surprisingly efficient fuel to produce electricity.
10% ethanol blend nicknamed "gasohol" is widely sold throughout the U.S. Midwest, and in cities required by the 1990 Clean Air Act to oxygenate their gasoline during the winter.

    chemistry   incl pharmacology & health
Small doses of ethanol generally produce euphoria and relaxation; people experiencing these symptoms tend to become talkative and less inhibited, and may exhibit poor judgement. At higher dosages, ethanol acts as a central nervous system depressant, producing at progressively higher dosages, impaired sensory and motor function, slowed cognition, stupefaction, unconsciousness, and possible death.

Anterograde amnesia, colloquially referred to as "blacking out", is a symptom of heavy drinking. Alcohol at high doses acts as an antagonist of the NMDA receptor; since the NMDA receptor is involved in learning and memory, this action is thought to be responsible for the "memory blanks" that can occur at extremely high doses of alcohol.

Hangover symptoms include dry mouth, headache, nausea, and sensitivity to movement, light and noise, partly due to the toxic acetaldehyde produced from alcohol by alcohol dehydrogenase, and partly due to general dehydration. Dehydration portion of the hangover effect can be mitigated by drinking plenty of water between and after alcoholic drinks.
Other components of the hangover are thought to come from the various other chemicals in an alcoholic drink, such as the tannins in red wine.

Regular light-to-moderate alcohol intake has been shown to have positive effects on health chiefly because of its cardiovascular effects. U.S. National Institute on Alcohol Abuse and Alcoholism extensive review of current scientific knowledge about the health effects of moderate alcohol consumption found that the lowest death rate from all causes occurs at the level of one to two drinks per day.
In persons who consume three or more drinks per day, total mortality climbs rapidly with increasing numbers of drinks per day

Research has found moderate drinking to be associated with lower risk of dementia, including Alzheimer’s disease, and reduces the risk of developing gallstones and kidney stones.
Compared to abstaining, drinking in moderation is associated with a reduced risk of stroke, whereas abusing alcohol is associated with an increased risk of stroke. A 2003 John Hopkins study has linked moderate alcohol use to brain shrinkage and did not find any reduced risk of stroke among moderate drinkers.

Drinking alcohol abusively over long periods of time increases the risk of developing alcoholism, alcoholic liver disease, and some forms of cancer. Chronic alcohol ingestion over many years can produce atrophy of the vermis, the part of the cerebellum responsible for coordinating gait. Large quantity consumption of alcohol can lead to alcoholic cardiomyopathy, commonly known as "holiday heart syndrome".

Fetal alcohol syndrome is a permanent birth defect that occurs in the offspring of women who drink alcohol during pregnancy. Alcohol crosses the placental barrier and can stunt fetal growth or weight, create distinctive facial stigmata, damaged neurons and brain structures, and cause other physical, mental, or behavioural problems.
Developing brain cells and structures are underdeveloped or malformed by prenatal alcohol exposure. Fetal alcohol exposure is the leading known cause of mental retardation in the Western world. Lifetime medical and social costs of each child with FAS are estimated as high as US$800,000.
The U.S. Surgeon General advises pregnant women to abstain from alcohol use due to this risk.

Based on its abilities to change the human consciousness, ethanol is considered a drug. Ethanol affects multiple systems in the brain, most notably as an agonist to GABA receptors. Similar psychoactives include those which also interact with GABA receptors, such as gamma-hydroxybutyric acid.
Alcohol appears to be hormetic, i.e.
has the opposite effect in small doses than in large doses. Alcohol has a biphasic effect on the body, which is to say that its effects change over time.

[ junk science ]
Drinking makes heart grow more sorrowful, study finds   2.29.08   AFP

Tokyo   Age-old belief may be that alcohol helps people drown their sorrows, but Friday a Japanese study said the bottle only makes bad memories linger.
Researchers at the University of Tokyo concluded that ethanol, does not cause memory to decrease, as widely believed, but instead locks it in place.

The researchers, led by pharmacology professor Norio Matsuki, gave mild shocks to lab rats to condition them to fear. As a result, the rats would freeze in terror and curl up the moment they were put in their cages.
Researchers then immediately injected the rats with ethanol or saline. The researchers found that rats with alcohol in their veins froze up for longer, with the fear on average lasting two weeks, compared with rats that did not receive injections.

    [ A severe negative conditioning methodology is very limited in the scope of conclusions it validates.
    Results predicated on psychological trauma cannot be logically assessed with high accuracy.

    Also, psychological analogy between rats and humans is not nearly as valid as physiological. ]

"If we apply this study to humans, the memories they are trying to get rid of will remain strongly, even if they drink alcohol to try to forget an event they dislike and be in a merry mood for the moment," the study said. "The following day, they won't remember the merriness that they felt," it said.   [ A highly interpretive assumption not supported by the facts stated in this article. ]

Matsuki said the findings offered lessons for people living with bad memories.
"To forget something you dislike, it's best to overwrite the negative memory with a positive memory at an early stage and leave out drinking alcohol," Matsuki advised. The study was published in the US academic journal Neuropsychopharmacology.

    [ These moralistic conclusions do not qualify for peer review or empirical verification. ]
Strong acid desiccants, such as sulfuric acid, cause ethanol's dehydration to form either diethyl ether or ethylene, predominanly depending on the precise reaction conditions.
Because it contains a double bond,
ethylene (C2H4) is called an unsaturated hydrocarbon or an olefin. It is extremely important in industry and even has a role in biology as a hormone.

Ethylene is the most produced organic compound in the world. Ethylene is an extremely important building block in the petrochemical industry. Ethylene polymerizes to produce polyethylene, also called polyethene or polythene, the world's most widely-used plastic. Ethylene is found in many lip gloss products.

Although ethylene is a relatively simple molecule, its spectrum is considered to be one of the most difficult to explain adequately from both a theoretical and practical perspective. Of particular note is the difficulty in characterizing the ultraviolet absorption of the molecule.
Depending on the concentration, ethylene gas can cause a pleasant odor, euphoria, nausea, hyperglycemia, a variety of psychological effects, blood pressure changes, hypoxia, loss of consciousness, or death. Ethylene has long been in use as an inhalatory anaesthetic. It shows little or no carcinogenic or mutagenic properties

Ethylene acts physiologically as a hormone in plants. It exists as a gas and acts at trace levels throughout the life of the plant by stimulating or regulating the ripening of fruit, the opening of flowers, and the abscission (or shedding) of leaves. It has been shown that ethylene is produced from essentially all parts of higher plants.
Ancient Africans would gash figs in order to stimulate ripening, since wounding stimulates ethylene production by plant tissues. The ancient Chinese would burn incense in closed rooms to enhance the ripening of pears. In 1864, it was discovered that gas leaks from street lights led to stunting of growth, twisting of plants, and abnormal thickening of stems.

DNA sequences for ethylene receptors have been identified in many plant species and an ethylene binding protein has even been identified in Cyanobacteria.
Environmental cues can induce the biosynthesis of the plant hormone. Flooding, drought, chilling, wounding, and pathogen attack can induce ethylene formation in the plant. One speculation recently put forth is downward pointing leaves may act as pump handles in wind to pump more water from the roots of the plants than would normally happen.

Ethylene shortens the shelf life of many fruits by hastening fruit ripening and floral senescence. Tomatoes, bananas, and apples will ripen faster in the presence of ethylene. Bananas placed next to other fruits will produce enough ethylene to cause accelerated fruit ripening. Ethylene will shorten the shelf life of cut flowers and potted plants. Plants can be induced to flower either be treated with the gas in a chamber or by placing a banana peel next to the plant in an enclosed area.

Ethylene hydration or brewing produces an ethanol-water mixture. For most industrial and fuel uses, the ethanol must be purified. Fractional distillation can concentrate ethanol to 95.6% by weight.
Absolute or anhydrous alcohol generally refers to purified ethanol, containing no more than one percent water. Absolute alcohol not intended for human consumption often contains trace amounts of toxic benzene used to remove water.
Generally this kind of ethanol is used as solvents for lab and industrial settings where water will disrupt a desired reaction. Pure ethanol is classed as 200 proof in the USA.
The German V-2 rocket of World War II used ethanol, mixed with water to reduce the combustion chamber temperature.

The Mallenby effect is the phenomenon whereby self-perceptions of the effects of alcohol on the person change between absorption and elimination phases of alcohol consumption. During absorption phase, individuals compare their perceived state with their condition before consuming alcohol. They tend to over estimate the effects of alcohol. During the elimination phase, they tend to underestimate their state of alcohol impairment

All humans always have some amount of alcohol in their bodies at all times, even if they never drink alcoholic beverages in their lives. Named endogenous ethanol production, many of the bacteria in the intestines use alcohol fermentation as a form of respiration. This metabolic method produces alcohol as a waste product in the same way that metabolism forms carbon dioxide and water.
within the human body is converted by the liver into acetaldehyde by the enzyme alcohol dehydrogenase and then into acetic acid by acetaldehyde dehydrogenase. The product of the first step of this breakdown, acetaldehyde, is more toxic than ethanol. Acetaldehyde is linked to most of the clinical effects of alcohol. It has been shown to increase the risk of developing cirrhosis of the liver, multiple forms of cancer, and alcoholism.

Next, the acetate is converted into fats or carbon dioxide and water. Chronic drinkers, however, so tax this metabolic pathway that things go awry; fatty acids build up as plaques in the capillaries around liver cells and those cells begin to die, which leads to the liver disease cirrhosis. The liver is part of the body's filtration system which, if damaged, allows certain toxins to build up, leading to symptoms of jaundice.
Some individuals have less effective forms of one or both of the metabolizing enzymes, and can experience more severe symptoms from ethanol consumption than others. Conversely, those who have acquired ethanol tolerance have a greater quantity of these enzymes, and metabolize ethanol more rapidly. Adverse reaction can be artificially reproduced by drugs such as disulfiram, which are used to treat chronic alcoholism by inducing an acute sensitivity to alcohol

Cell membranes are highly permeable to alcohol, so once alcohol is in the bloodstream it can diffuse into nearly every biological tissue of the body. Frequent use of alcoholic beverages has also been shown to be a major contributing factor in cases of elevated blood levels of triglycerides.

Ethanol itself is not a carcinogen, but effects on the liver when ingested can contribute to immune suppression. As such, ethanol consumption can be an aggravating factor in cancers resulting from other causes.

Extreme levels of consumption can lead to alcohol poisoning; concentration in the blood stream of 0.55% will kill half of those affected. Death from ethyl alcohol consumption is possible when blood alcohol level reaches 0.4%. Levels of even less than 0.1% can cause intoxication, with unconsciousness often occurring at 0.3-0.4%. Death can also occur through asphyxiation by vomit. An appropriate first aid response to an unconscious, drunken person is to place them in the recovery position.
In America, about half of the deaths in car accidents occur in alcohol-related crashes. Most drunk driving laws governing acceptable levels in the blood while driving or operating heavy machinery set typical upper limits of between 0.05% or 0. 08%. Ethanol interacts in harmful ways with a number of other drugs, including barbiturates, benzodiazepines, narcotics, and phenothiazines.

Ethanol kills organisms by denaturing their proteins and dissolving their lipids and is effective against most bacteria and fungi, and many viruses, but is ineffective against bacterial spores. When applied to open wounds for disinfection, it produces a strong stinging sensation. Pure or highly concentrated ethanol may permanently damage living tissue on contact.

Ethanol properties stem primarily from the presence of its hydroxyl group and the shortness of its carbon chain.
Ethanol's hydroxyl group is able to participate in hydrogen bonding, rendering it more viscous and less volatile than less polar organic compounds of similar molecular weight. Ethanol's hydroxyl proton is very weakly acidic, even weaker than water. The pH of 100% ethanol is 7.33, compared to 7.00 for pure water.

Hydrogen bonding causes pure ethanol to be hygroscopic to the extent that it readily absorbs water from the air. The polar nature of the hydroxyl group causes ethanol to dissolve many ionic compounds, notably sodium and potassium hydroxides, magnesium chloride, calcium chloride, ammonium chloride, ammonium bromide, and sodium bromide.
Because the ethanol molecule also has a nonpolar end, it also dissolves nonpolar substances, including most essential oils, as well as numerous flavoring, coloring, and medicinal agents.

Several unusual phenomena are associated with mixtures of ethanol and water. Ethanol-water mixtures have less volume than their individual components. A mixture of equal volumes ethanol and water has only 95.6% of the volume of equal parts ethanol and water, unmixed (at 15.56 °C).
The addition of even a few percent of ethanol to water sharply reduces the surface tension of water. This property partially explains the tears of wine phenomenon. When wine is swirled in a glass, ethanol evaporates quickly from the thin film of wine on the wall of the glass. As its ethanol content decreases, its surface tension increases, and the thin film beads up and runs down the glass in channels rather than as a smooth sheet.

Combustion of ethanol forms carbon dioxide and water. Ethanol mixture with water greater than 50% ethanol are flammable and easily ignited. This principle was used for the alcoholic proof, which initially consisted on adding gunpowder to a given liquor: if the mixture ignited, it was considered to be "100 proof".
Ethanol-water solutions below 50% ethanol by volume may also be flammable if the solution is vaporized by heating, as in some cooking methods that call for wine to be added to a hot pan, causing it to flash boil into a vapor, which is then ignited to "burn off" excessive alcohol.

Ethanol is produced both as a petrochemical, through the hydration of ethylene, and biologically, by fermenting sugars with yeast. Which process is more economical is dependent upon the prevailing prices of petroleum and of grain feed stocks.

Breweries and biofuel plants employ two methods for measuring ethanol concentration.
Infrared ethanol sensors measure the vibrational frequency of dissolved ethanol, using a relatively inexpensive solid state sensor that compares the CH band with a reference band to calculate the ethanol content via the Beer-Lambert law.
Alternatively, by measuring the density of the starting material and the density of the product, using a hydrometer, the change in specific gravity during fermentation indicates the alcohol content. This inexpensive and indirect method has a long history in the beer brewing industry.

There are 3 major subsets of alcohols: primary (1°), secondary (2°) and tertiary (3°), based upon the number of carbon atoms the C-OH group's carbon is bonded to. Ethanol is a simple 'primary' alcohol. The simplest secondary alcohol is isopropyl alcohol, and a simple tertiary alcohol is tert-butyl alcohol.
The simplest and most commonly used alcohols are methanol and ethanol. Methanol was formerly obtained by the distillation of wood and called "wood alcohol." It is now a cheap commodity. Methanol is intoxicating but not directly poisonous. It is toxic by its breakdown by the enzyme alcohol dehydrogenase in the liver by forming formic acid and formaldehyde which cause permanent blindness by destruction of the optic nerve

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