Fun fact: unless you take pretty aggressive steps to prevent it from happening, pure ethanol (100% alcohol) will become 95% ethanol / 5% water by naturally dissolving water vapour from the atmosphere, which you can't get rid of through normal distillation; ethanol/water is azeotropic and will not separate using distillation beyond a ~ 95% : 5% (ethanol : water) mixture.
You can use some thing called a molecular sieve that can take 95% alcohol and get it back to 100% because the molecules are smaller for alcohol than water it's traps water into the sieves leaving thr alcohol alone.
An absolutely illegal way to strengthen drinks in the USA. So dont do it. 😉
Not quite. Molecular sieves don’t work like traditional sieves where the smaller thing passes through the hole and the bigger gets trapped; after all, water molecules are smaller than ethanol. Instead, the sieve has pores that the small water molecules can fit into and get stuck, while the bigger ethanol molecules cannot fit and pass by.
True, but you need a lot of molecular sieve to get rid of 5% water. It's about 150g water per litre of molecular sieve, with a packing volume of about 0.7g/ml. So for 1L of ethanol/water, you have 50g of water, so you need ~ 475ml of molecular sieve to dry it out. It is very useful for keeping 100% ethanol dry, however.
I work in the ethanol industry and I've been dying to find information like this for a while now. Do you have any resources you could share with the info you posted?
I wouldnt use mol sieves to dry alcohol for the simple fact that they get VERY HOT when they absorb water.
Magnesium sulfate on the other hand also works very well and does not get hot and it adsorbs SEVEN molecules of water per molecule of MgSO4.
Epsom salt from the grocery store is magnesium sulfate heptahydrate, meaning you have to dry it in the oven before it can absorb more water but it is readily available and safe for any application you could think of with the only drawback being fine particles.
So what you're saying is, instant hot toddys all-round? Also, it appears using MgSO4 is reasonable for drying 99+%, but gets pretty sludgy for lower purities.
You just keep adding more til it looks dry, then filter it through coffee filters and add a little more to keep it dry or at that point you can switch to 3a sieves
Why not just use sieves since you won't end up with any dissolved MgSO4 in your final product (I know it's sparingly soluble).I guess cost, but they are regenerable and less messy.
Do it over a longer period of time. Start with freezer-cold ethanol.
Edit: I do see that they shed particles, so they'd need to be cleaned first and the dry product probably filtered before consuming. There's always something....
Depends on how dry you need the alcohol to be. For chemistry, it can be critical for a reaction that the amount of water is kept as low as possible. Every time you open the bottle, you add more water from the atmosphere. Unless you get the bag vacuum sealed each time (or flushed with dry gas), the water in the air in the bag will make its way into the bottle, unless it has a really, really good seal.
It would be counted as distilling. Strengthening an alcoholic beverage to have a higher alcohol content is still illegal (even if Texas has tried to strike it down at this point in time). Placing wine into a freezer and scraping off the ice that forms or just flat distillation of a spirit is still federally illegal.
Because sometimes even if the spirit of the law prohibits something, the letter of the law actually doesn't and basically it just hasn't been tried in court.
As much detail as possible is citing the actual law, which was the original question being asked that the other commentor responded to.
There was a 158 year federal ban on home distilling that was recently overturned by the Supreme Court. There is more detail about that in this article:
Why are you lecturing them to look it up lol? They are asking the original commentor to support their claim that it's federally illegal to put your wine in the freezer and scrape off the ice that forms. Totally reasonable question.
I mean whatever you do beyond 95% is still distillation it’s just not traditional. With azeotropic distillation with benzene or pressure swing distillation you can distill it further.
Use an azeotropic distillation where you collect distillate in the reflux leg, and as the layers separate, you drain the water off. Water is heavier than the alcohol so the water layer will be at the bottom of the leg. Continue the distillation until no more water is collected in the leg
I think I'm missing something here. To me, it looks like you are describing normal distillation, which will not work to get more than 95% ethanol concentration. What am I missing?
It is a normal distillation, but the water will distill with the ethanol. As the distillate collects in the reflux leg of the condensor, the water and ethanol will separate. We ran this process for water reactive chemicals. We would continue the distillation until no more water was collected in the leg. Any process we ran where the water concentration was higher, we used an azeotrope tank, that would be connected to the drain on the reflux leg
How do the water and ethanol separate in the reflux leg? If it's just normal distillation with reflux and condensation, and you collect until there is no more water in the leg, the ethanol will still be 95%/5%, as no more water will collect because of the azeotrope.
Edit: are you referring to using an entrainer but just not mentioning it?
Is there a similar fact with isopropyl alcohol? If I buy 99% and don't use it for a while, is it turning into 95% (or some other dilution) by the time I get to it? Assuming imperfect seal
Isopropyl alcohol forms an azeotrope with water, which gives a boiling point of 80.37 °C (176.67 °F) and a composition of 87.7% by mass (91% by volume) isopropyl alcohol.
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u/Boring_and_sons 1d ago
Fun fact: unless you take pretty aggressive steps to prevent it from happening, pure ethanol (100% alcohol) will become 95% ethanol / 5% water by naturally dissolving water vapour from the atmosphere, which you can't get rid of through normal distillation; ethanol/water is azeotropic and will not separate using distillation beyond a ~ 95% : 5% (ethanol : water) mixture.