We often refer to alcoholic beverages as adult beverages. Yes, we adults often enjoy a nice adult beverage. These come in all shapes and sizes and colors to boot. A little can leave you feeling nice or even a little tipsy. A lot can lead to being drunk which has its own set of problems a mile long that I will not address. A whole lot can actually kill you. So tread softly with your choice of adult beverages and read the "rule book" so to speak so that laws are obeyed and not broken.
Now that we know what I am talking about, lets dive into more of the science/chemistry that is envolved with the making and partaking of alcohol. First, we say "alcohol" and what that really means is "ethanol" which is a specific compound among the broader class of alcohols in organic chemistry. As a matter of fact, lets look at a few common compounds that are all alcohols and what they are used in.
Also known as wood alcohol - it is the simplest alcohol with the formula CH3OH. It is also a primary (1°) alcohol, meaning the carbon the hydroxyl is attached to is attached to only one other carbon. Don't drink it! It is a poison and should never be confused with ethanol. One ounce (only 2/3 of a shot) can kill you. And, it is possible you can ingest this unintentionally by drinking what you think is just ethanol. This is possible when quality standards in making ethanol through fermentation are not followed - careless creation and treatment of the fermented liquid can make methanol along with ethanol. As a matter of fact, methanol is typically made in small amounts when fermenting to get ethanol. The trick is to remove it during distillation. Scary stuff - just be careful of your neighborhood "backyard distiller" and their special moonshine concoction. From a scientific standpoint, methanol is a nice and helpful solvent for many organic reactions and it is major component in fuel additives.
This is rubbing alcohol. The hydroxyl group is attached to an isopropyl group. This means it is propane with the hydroxyl group on the middle carbon (CH3)2CHOH. They sell it in two general strengths of 70%, and 91%. If you look hard, you can also find it at 99%. Even though it is a polar compound due to the hydroxyl group, it has a lot of non-polar character thanks to its hydrocarbon framework. This means it is a pretty good solvent for many non-polar compounds. It is sometimes mixed with water (and sometimes methanol thrown in as well) to make a low freezing windshield washer fluid that has no residue.
I'm including this because there are those that wonder - "Why is ethanol so cheap when it is in the paint section at Home Depot?"... and then ask, "Why can't I buy the ethanol at Home Depot and then just add it to my drinks at home?" Whoa - that is a terrible idea. Why? Because the "denatured" in that title should tell you it is NOT natural alcohol. There are also numerous warnings on it to not consume it because it is a poison. It IS considerably cheaper than drinkable alcohol though - runs around $30/gal which would amount to around $6 for a 750 mL "fifth". As a point of reference, 750 mL of Everclear, which is 95% Ethanol, 5% water and is drinkable without dying, is around $15 per 750 mL. The reason for the price difference is that they don't tax "denatured" alcohol and the regulations are much lighter, thus cheaper to produce and sell. How do they "denature" the alcohol? They add other solvents to it and those solvents render it totally unsuitable to drink. For example one type of "denaturated ethanol" is 85% ethanol, 5% isopropyl alcohol, 5% methanol, and 5% methyl isobutyl ketone. That is probably a great solvent or paint stripper - but it is a terrible and poisonous drink. And do you think you'll just distill the denatured alcohol and make it pure? Think again... even though those components dont' form true azeotropes (see further down this page) with ethanol they will still partially come across in any distillation attempts which still keeps the ethanol undrinkable. The bottom line is that you could spend far MORE money just trying to extract your cheaper ethanol from denatured ethanol than the cost of just buying the premium taxed and drinkable ethanol.
YES, this is the one you CAN drink. Ethanol is also known as grain alcohol. Yes, this is the one in adult beverages. Booze. As previously mentioned, this one carries a lot of federal and state regulations plus excise taxes. So having an adult beverage has some built-in pricing hikes vs a non-alcoholic alternative. Also, very important to know - ethanol can be very pleasant and therapeutic in small doses. But over do it and it becomes lethal. Alcohol overdose is a real problem. Large quantities (like a whole bottle or fifth of vodka) can kill you. So how much can kill you? There are many factors at play on that question. It depends on many factors - some of which are body mass, age, previous experiences drinking alcohol, and most important: time and amount. Chugging a fifth is like playing Russian Roulette with more than one bullet in the chamber. Very risky for ALL parties involved in that undertaking. Let's move on to more quantitative things.
For reasons of tradition and ease of measurement, alcohol content in a beverage or spirit is given in percent ABV units which are percentage alcohol by volume. This means you can think of that 12 oz beer that is at 5% ABV as having 0.6 oz of pure ethanol in it - note that 0.6 is 5% of 12. Now if you want to know how many grams of ethanol that is, we have a few more calculations. When I look up the density of ethanol I find that it is 0.789 g/mL. So now I need my fluid ounces to milliliters conversion factor (29.57 mL/oz) to do the conversion. See below for the whole beer to grams of ethanol calculation.
12 oz beer(5%) = 0.6 oz of ethanol
0.6 oz ethanol (29.57 mL/oz) = 17.742 mL of ethanol
17.742 mL ethanol (0.789 g/mL) = 14.00 g of ethanol
OK, so 12 oz of beer - or any beverage that is 5% ABV (like a White Claw) has 14 grams of ethanol in it. Those 14 grams have about 7 Calories each which clocks out at 98 Calories just from the ethanol. And yes, that 7 calories is a rounded number so it is actually a tiny bit less (low 90's). The point being that if you are going to have an alcoholic beverage that is at least 5% ABV and 12 oz in volume, you are going to get at least 98 calories or higher.
To somewhat normalize the amount of alcohol in "all" adult beverages, the serving-size volumes are adjusted based on ABV to yield those same 14 grams of ethanol (or 0.6 oz) in all drinks. These are "normal" drinks as in the kind you can easily count. Drinking guidelines will tell you not to have more than a certain number of drinks in a given amount of time. So doing a little more math, but this time going the opposite direction from the 14 g...or even easier, from the 0.6 oz of ethanol, here are some "standard" amounts for various adult beverages.
|beer||5 %||12 oz|
|wine||12 %||5 oz|
|liquor||40 %||1.5 oz|
Note that ANY mixed drink, like a rum and coke, or vodka/soda, will have (or should have) that same "shot" of liquor of 1.5 oz in the drink which means the same amount of alcohol. All this changes when you get a stiff drink with more than one shot in it - or multiple shots of different liquors (I'm talking to you Long Island Iced Tea). To say you only had "one drink" is misleading when that one drink has 4 or 5 shots of liquor in it. The same applies to bigger beers with higher ABVs. I'll give you a real example of how a single beer is really two beers in the old traditional "drink" way of counting.
Local brewery and popular hang out for types like myself have beer mugs that happen to be "metric" in that the fill line on the mug is a half-liter or 500 mL. That is more than the traditional pint of 16 oz - but just a little more 500mL/29.57 mL per oz is 16.9 oz which isn't much, but it IS more and they typically go just over the mark - so let's just call it 17 oz. Now on top of that, I decide to have a higher ABV beer (their Big Mama Red) that clocks in at 7.9% ABV. So how many grams of ethanol do I get in that one beer? Do the math.
(17oz)(7.9% ABV)(29.57mL/oz)(0.789g/mL) = 31.3 g of ethanol
Whoa - not anywhere close to those 14 grams of a normal beer at 5% ABV and 12 oz. It is roughly 2.25× the amount of alcohol in a "normal" beer at a "normal" quantity. There ARE bigger drinks with bigger ABVs than that Big Mama Red. You can figure out just how much alcohol you are getting on those big-ass drinks if you just "do the math". You can get totally inebriated in a very short amount of time by just having "two drinks". Your body can only metabolize so much alcohol in a given amount of time and those ABVs will translate to BACs quickly. What's a BAC? That is a blood alcohol content amount and above 0.08% you are officially drunk by Texas Law standards and you will be arrested if driving a vehicle. That is driving while intoxicated - a DWI. Take home lesson - know what you're drinking, how much your drinking and what that can lead to.
There is a reason that ethanol that has been distilled numerous times only reaches about 95% ethanol and 5% water. First, ethanol and water are infinitely miscible - meaning they can be mixed in any set of ratios and they will perfectly mix to give a homogeneous mixture - a solution if you will. Any mixture with more than 5% water... like a freshly fermented batch of soon to be "spirits"... can be distilled to get more and more ethanol out of the mixture. Ethanol boils at 78.37 °C while water boils at 100 °C. A mixture of the two generally boils at a temperature somewhere between the two boiling points as long as the water component is more than 50%. Above that, and the boiling point starts to depress (lower) below 78.4 because of colligative effects. Brushing over that bit of science let's just say that at 95.6% ethanol and 4.4% water, the solution is now an azeotrope. An azeotrope is a mixture of liquids that go from liquid phase to gas phase with no change in composition. So once you enrich your ethanol to 95.6%, it will stay that way, even if you keep distilling it over and over. Many liquids/solvents form azeotropes.
Sometimes in laboratories we need 100% ethanol with absolutely no water. It is called absolute ethanol. In order to make it you have to first get the 95.6% ethanol azeotrope. Then you need to chemically remove the water. One way to do this is to set up a reflux apparatus. A reflux is a steady boil but with all the evaporated liquid dripping back into the flask - basically like how you simmer a pot of soup on the stove with the lid on. To remove the water you can add and active metal such as magnesium turnings (little magnesium shavings). The magnesium will react with the water to make insoluble magnesium hydroxide.
Mg(s) + 2H2O(ℓ) → Mg(OH)2(s) + H2(g)
The magnesium is added in excess such that all the water is removed as the insoluble hydroxide. The hydrogen gas is vented off as well. After this refluxes for a day you then tap it just like a distillation now - but the distillate is now 100% ethanol ready to use in the laboratory.