- Early on in the pandemic, it was nearly impossible to get distilled water.

I needed some because I wanted to grow my own crystals.

We all grew our own crystals early on in the pandemic, right?

Anyways, I decided to distill my own water.

(pot clanking) (ice cubes clattering) (burner clicking) (water bubbling) But what if I wanted, let's say, a bourbon?

Why am I not allowed to distill whiskey at home?

(upbeat music) (alcohol splashing) - Yeah, it's a little high proof.

- The principle behind distilling anything is simple.

You heat a solution to separate the different components.

To distill liquor, you heat up a fermented solution that contains ethanol, like wine or beer.

You boil off the alcohol, leaving the water behind.

Now collect the concentrated ethanol, you've got liquor.

So, why does that work?

Well, because water and ethanol have two different boiling points.

Why do they have different boiling points?

That's where you start getting into the good stuff.

By looking at the molecules up close, we can actually see the answer to this, and at least in part, why I can't make one of these from scratch.

And to figure out why I can't do this at home, I wanted to at least see how it's done professionally.

So, meet Alex.

He is a master distiller at One Eight Distillery in DC.

In the greater alcohol market, this is considered a small distillery, but I didn't expect to see a still that small.

And if you're wondering, a still is a device used to distill ethanol.

- This is a great little still, believe it or not.

We do use this for some of our small batch production.

The name of this still is Al Ambiq.

It is an alembic-style still.

- It makes a lot of sense to try new recipes on a small still.

It's quicker, it's easier, it's less waste if it doesn't work out.

But the principle of distilling is always the same regardless of the size.

That small size still, though, has just really cute moonshine vibes to it.

- So, that that ethanol vapor will come up, go through this, the lyne arm.

And then we hook this up to some cooling water in and out.

And as that vapor goes down the worm, the coil there, it will cool, condense, and then drip off, and we'll collect that product.

- All right, now, let's back up, here.

We're using a still to separate ethanol from a solution.

But where did that solution come from?

It came from the first major step in the process of making liquor, fermentation.

Now, fermentation is something we've covered before.

Well, not me.

This is my first video with "Reactions".

Hey, I'm Sophia, by the way.

But the collective we (bell chiming) have talked about fermentation before.

Alcohol, kombucha, even pizza dough, it's all basically the same process.

Fermentation is the process where yeast turns sugar into alcohol.

But yeast can only make a relatively low concentration of ethanol, so we do all this fancy distilling stuff to get that concentration higher than the yeast itself can yield.

Fermentation makes a lot of different products, not just ethanol.

Depending on what kind of liquor we're making, we might want some of those other products.

On the other hand, some of the products of fermentation are poisonous, so we really don't wanna be making concentrated solutions of those chemicals to drink.

So, how does a still allow us to keep what we want and leave out the rest?

The basic way it works is by taking the fermented beer, which is called mash, this one was made out of corn and rye, and heating it up.

Now, separating the ethanol from the water is pretty straightforward, and it has a lot to do with its molecular structure.

Here is what ethanol looks like and this is what water looks like.

Notice the similarity?

Both have that OH group at the end, one oxygen, one hydrogen.

That group, when attached to a hydrocarbon like this, is what makes alcohols alcohols.

If we take away that OH group and replace it with just hydrogen, then we have ethane.

Ethane is not an alcohol.

Ethane boils from a liquid to a gas at negative 89 degrees Celsius.

Ethanol, on the other hand, boils at 78 degrees Celsius.

That's a pretty big difference, and it's all because of that OH group.

That's because within the OH group, the oxygen pulls the electrons just a little bit harder than the hydrogen does, so the hydrogens are a little bit more positively charged and the oxygen a little bit more negatively charged.

The oppositely charged sides are attracted to the neighboring groups like magnets.

In this case, the partially positive hydrogen on one molecule is attracted to the partially negative oxygen on the other molecule.

This is called hydrogen bonding, and it's important.

Since water has two hydrogens bonded to oxygen where ethanol only has one, water has more opportunities for hydrogen bonding.

More hydrogen bonding means the molecules hold on to each other more.

That means a higher boiling point.

So, on a molecular level, what is happening is that the bonds between the ethanol molecules break more often than the bonds between the water molecules.

- And we want to concentrate the ethanol.

So, the way we can do that, distilling, will heat up the solution past the boiling point of ethanol, which is approximately 173 degrees Fahrenheit, but keep it below the boiling point of water to 12 degrees.

- The machinery here automatically heats up the mash slightly above ethanol's boiling point.

The ethanol boils into a vapor moreso than the water.

The vaporized ethanol travels up all of those tubes.

All the while the vapor cools, it is condensing into a very strong alcoholic solution.

- Feel free if you'd like to sample some.

(alcohol splashing) (Sophia laughing) - There are two types of forces holding everything together when something is a liquid, intra and intermolecular forces.

A single water molecule, for example, is formed with very strong covalent bonds between the two hydrogen and one oxygen atom.

For this type of intramolecular force, the attractive forces that hold the atom together is something within the molecule.

When we zoom out a little bit, we are looking at the surrounding molecules and how they interact, those of the intermolecular forces.

The stronger the intermolecular forces within any liquid, the more energy or heat is needed to break them.

And there are several types of intermolecular forces out there.

The weakest are the London dispersion forces which all molecules exhibit.

London dispersion forces are the result of electrons moving around.

Sometimes that random movement causes a temporary charge on one molecule.

So, if the electron density happened to be on one side of a molecule, that side would become a little more negatively charged, and on the other side, a little more positively charged.

On non-polar molecules, like ethane, these London dispersion forces are the main interactions holding the molecules together.

The longer the chain of carbons, like in propane, butane, or octane, the more opportunities for these intermolecular interactions, so a higher boiling point.

But both water and ethanol bond to one another using something stronger than the London dispersion forces.

They use hydrogen bonding.

And again, that's thanks to that OH group.

Hydrogen bonding is much stronger than the London dispersion forces.

That difference is the reason water boils at a higher temperature than ethanol.

The intermolecular forces between the OH groups are much stronger than those between the hydrocarbon chains of roughly the same size.

Remember how ethanol is very similar to ethane?

Well, ethane is a component of natural gas, and like natural gas, with the right amount of heat, ethanol's hydrocarbon chains can break apart and react with oxygen.

This process is called combustion, and it's the first big snag in my pursuit to distill my own alcohol.

Ethanol in any form is flammable, and as a highly concentrated vapor, it can be explosive.

We're using heat to separate ethanol from water.

Heat plus a potentially explosive vapor, see the problem, here?

- We have emergency doors that would slam shut in the case of an emergency.

A lot of the valves on the system are powered by compressed air.

All of the electrical elements, we do have to have a few, are built to the explosion-proof standards.

- Professional distillers have to be very careful about this.

They've built their whole distillery to avoid combustion and to contain it If it does happen.

That level of safety is a little harder for me to pull off in my kitchen.

Combustibility isn't the only dangerous aspect of distilling, though.

There's one particularly undesirable ingredient produced by fermentation.

Structurally, it is very similar to ethanol, but it's a poison, methanol.

When you're trying to concentrate the ethanol produced by fermentation, you have to be careful not to concentrate the methanol along with it.

- That could be a little bit of methanol, could be a little bit of isopropanol.

The metabolism of yeasts, they get a little confused, and once in a while, they don't make ethanol.

Our sensory, our sense of taste and smell is our most important tool as distillers.

Come through, and just run my fingers through.

A little sensory smell first.

If I didn't smell anything, then I would taste.

If I didn't taste any of those higher alcohols, that isopropanol, et cetera, then I could collect the hearts of the run.

- History break.

You might have heard of the dangers of methanol during prohibition.

I was personally under the impression that moonshine can make you go blind from crude distilling practices.

While that is possible, the full story is actually much darker.

Prohibition was largely driven by concern about morals, and there's a lot of evidence to the deleterious effects of alcohol on society.

But the government deliberately poisoned wood alcohols used for industrial purposes with extra methanol, knowing people would use it in their bootleg liquor.

It's estimated that about 10,000 people died as a result of ingesting deadly methanol.

However, in general, a lot of people died from alcohol during this time, and recent research suggests that most of that was regular ethanol overdose.

So, a huge factor in all of those moonshine-related deaths during prohibition was just that people were drinking way too much liquor.

But methanol is a serious problem.

You really don't wanna be drinking any of it.

So, how do we separate the methanol from everything else produced in fermentation?

Alex explained that the best way to avoid non-essential components like methanol is just throw out the first few gallons of distilled liquor.

It's called the heads of the batch.

Both methanol and ethanol hold on to molecules with intermolecular hydrogen bonding.

But they also have London dispersion forces going on in between their hydrocarbon chains, although in methanol, that chain is really just one carbon.

A longer carbon chain means more opportunities for London dispersion forces, which makes ethanol boil at a bit of a higher temperature than methanol.

Because methanol has a slightly lower boiling point, it boils off first.

- Those, thankfully, will come off the still, since they have a lower boiling point than ethanol, at the beginning of the run.

- There are even more compounds that arrive at the end of the run, in the tails, which are called fusel alcohols or fusel oils.

You've got your isoamyl alcohol, your 2-methyl-1-butanol, your 1-propanol, and so many more.

And since these have more carbons than the ethanol, they also have more opportunities for London dispersion forces, and they boil at slightly higher temperatures.

It's all still lower than the boiling point of water, but higher than ethanol, which is why they tend to show up at the end of the distilling run.

These alcohols have all kinds of flavors, and while extra flavors are not particularly desirable for something like vodka, they just add a bit of pizazz to today's bourbon.

- Again, for vodka, we don't want any of that.

We won't collect any.

But for our whiskey, we do want some of the funkier flavors, those fusel oils to come through just a little bit.

After it comes off the pot still, we will measure the proof, weigh it, and then we'll add water to bring it down to 115 proof, because at 115 proof, that's where we'll fill our barrels.

- So, after years of sitting in that barrel and a lot of small samplings along the way.

- [Alex] There we go.

- [Sophia] A new bourbon is ready.

(bright jazz music) - It's gonna be a high proof.

It's probably come up in the last four years to over 120.

Yeah.

- Brief recap.

The process of boiling ethanol from a fermented mixture may sound simple.

Just heat that mash to ethanol's boiling point, dump methanol, and maybe just let it sit in a barrel for 18 years.

The fact that ethanol's intermolecular forces are weaker than water's means that we can boil that specific molecule to separate it and cool it so it condenses mostly as pure ethanol.

The process does take some highly specialized equipment to make it safe.

I personally wanna keep my eyesight, don't particularly wish to blow anything up, and bottom line, who has the patience to wait five years for a decent whiskey?

So, for now, I'll just have a little bit of what Alex made.

Thank you, Alex and One Eight Distilling.

Be careful out there.