What can you add to a bottled drink to lower the freezing point (other than salt)?

Submitted by UncommercializedKat t3_y7daqw in askscience

I'm curious if there’s anything (food safe of course) that you can add to a bottled drink that will lower the freezing point. Ideally, it would have a minimal effect on the taste.

I know salt will. What else?

EDIT: I saw a reply in my email that doesn't seem to appear here. Someone mentioned that it could be dangerous to drink a liquid that was below the freezing point of water because it could cause body parts to freeze. I am looking for a modest decrease in freezing point, around 10-20F below the normal freezing point which shouldn't be much more dangerous than drinking an alcoholic drink that's below 32F or chewing ice.

The purpose of this inquiry is to make a sports drink that could be kept liquid below 32F

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ECatPlay t1_isvib80 wrote

Sticking with nontoxic chemicals, several come to mind that could be used to significantly depress the freezing point of water in a bottled drink. Ethanol, of course, but that would affect the flavor and be intoxicating. Sugars dissolve well and will depress the freezing point but will also sweeten the drink, some more than others. Another carbohydrate, glycerin, will sweeten the drink too, but not by as much. And then there's propylene glycol, which is nontoxic, has only a slightly acrid taste, and is sometimes used as an antifreeze in brewing.

These aren't all equally effective. You can compare the wt% concentration necessary to drop the freezing point of water by a given amount, from a table of CONCENTRATIVE PROPERTIES OF AQUEOUS SOLUTIONS. I find, for example, that for a 1° C drop in freezing point it would take about: 2.5% ethanol, 4% propylene glycol, 5% glycerin, 9% D-glucose, or 15% sucrose. (Salt would only take 1.7 wt%.)

So glycerin would be the most effective of the these carbohydrates, and least sweetening. And propylene glycol would be effective with minimal affect on taste.

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ArtesianDiff t1_isvr6a9 wrote

Would glycerin also work for lowering the freezing point of a solid? For instance, cherries in ice cream. Alcohol is used to keep them from freezing hard in some adult ice creams, but an alternative for children sounds interesting.

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ECatPlay t1_isvrxgl wrote

Theoretically yes, but you'd have to get twice as much in, and I'm not sure it would permeate into the cherry as easily as alcohol.

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UncommercializedKat OP t1_isvzw1d wrote

Thanks for the info!

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Chu_BOT t1_isw1tay wrote

I'm very curious why you're asking this. It seems oddly specific, like you're trying to play a prank.

You might consider supercooling depending on what your exact needs are:

https://youtu.be/5T68TvdoSbI

You can end up with a liquid at a temperature lower than normal without any chemical changes.

But I do think there might be options besides freezing point depression if you give more detail about the expected outcome instead of just the method you're asking about.

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UncommercializedKat OP t1_iswacrk wrote

No pranks. I have an idea for a consumer product and I'm researching the viability.

What I'm looking for is to make a sports drink that would be resistant to freezing. I don't have a specific temperature in mind, although it would be really great if it could be kept from freezing in a normal household freezer (0F or -18C).

Cost, taste, and food safety are all vital so I'm not sure how low it could feasibility go. I've heard that Gatorade freezes at 18F (-8C) but haven't done any experimenting.

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CausinACommotion t1_iswtt7r wrote

Gastrointestinal problems might be real concern, when you start adding additives to reduce the freezing point. Osmotic diarrhoea is a nasty thing.

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Limp_Result7675 t1_isvze6f wrote

You can also take your liquid (assuming it’s water) to a higher pressure (3000-4000 times that of air at sea level) and that should depress the freezing point as well. Might be useful if you want to have a cool beverage while free-falling through Jupiter’s atmosphere. Maybe Randal Monroe of XKCD wants to run with this option ;)

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