The Science of the Brain Freeze: The Origin of the Slurpee, and the Ice Cream Headache

Posted by Eric Troy on 24 Mar 2012 18:31

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There is something about the ice cream headache. Maybe you know what I'm talking about. It is nothing short of agonizing, and yet as kids we would purposely eat our ice cream cone too fast to bring one on. And then scream, partly in pain and partly with the thrill of it. I guess it's sort of like a roller are in control. It is a well-known phenomena that pain is more easily tolerated when it is known to be temporary and its cause known to be benign. And, it's one of the few instances where you can intentionally cause yourself intense pain of a temporary nature. Too bad about the brain damage, though…

Just kidding. It's harmless. Good thing too, because at some point, in the 1950's, this guy named Omar Knedlik, who owned a Dairy Queen in Coffyville, Kansas, got fed up with how inefficient the ice cream cone was at producing a brain freeze, and invented a machine to make frozen drinks called an ICEE. After that, you could produce the headaches by the dozen.

If you grew up in a 7-Eleven land, you may never have had an ICEE. That's okay, you know what I'm talking about. A 7-Eleven Slurpee is the same thing. In the 1960's, 7-Eleven licensed the drink from the the ICEE company, but they had to sell it under a different name, so they called it a Slurpee. Plus, they could only sell it in U.S. 7-Eleven stores. This prevented direct competition between the 'two' drinks. It also created the myth that the Slurpee and ICEE are two different things, a debate I still have with people to this day.

It was Omar who invented the FCB (Frozen Carbonated Beverage), and this was after a happy accident in which he froze his sodas to a slushy consistency and his customers loved it.

There are two types of people: those who despise 7-Eleven and condemn it as an example of capitalism gone wrong, right up there with Walmart, and those who live by it, subsisting on microwave burritos and Big Gulps. Those who love the store, purists, insist that their beloved C-store could never have NOT came up with the drink all on its own.

However, the ICEE company is still going strong and you can still get an ICEE in plenty of places. We didn't have 7-Elevens where I grew up, but we did have convenience stores and "mini marts" who sold Icees, which the person behind the counter had to dispense for you…the way it used to also be at 7-Eleven.


ICEE, the original.


ICEE, the original.

Incidentally, some old-timers I knew would call any convenience store a "totem store" or a "totsem" store. Totem stores were what 7-Elevens were before they were 7-Elevens, starting as The "South China Ice Company", which sold ice to businesses, and then opened its doors to individual consumers, before expanding to other "convenience items". The store put a Totem pole out front, and the Totem Shop was born. Why people from down my way would call convenience stores a totem store, I'm not really sure, but it could just have well have been their remembrance of an obvious imitator, the "U-Totem" Store, which became a fairly large chain before being bought by the Circle K corporation.

Another wrench in ICEE/Slurpee debate is the term "slushee". The ICEE was a "slushy" drink. Sometimes, you might come across a drink called a Slushee, not founded until 1996, which is thinner than an ICEE/Slushy. Yet some people insist on getting the ICEE mixed up with this Slushee, causing more confusion.

No, they are NOT the same thing with a different name! Slurpee and ICEE are the same thing with a different name, but Slushee is a different drink. There is also the "Slush Puppie" which is also owned by the ICEE company, but sucks. You'll find these in gas stations and lower end places, and the machines do not work the same. They are the ones with the big clear swirl canisters. Unlike an ICEE, which holds itself together well, you can suck the "flavor" of a Slush Puppie right out of the ice.

frozen blended margarita with lime wedge

Did you know that the Frozen Margarita and the
Slurpee are connected? Read on to find out how.

frozen blended margarita with lime wedge

Did you know that the Frozen Margarita and the
Slurpee are connected? Read on to find out how.

The Circle K corporation, which I mentioned above, owns the second largest chain of convenience stores next to 7-Eleven. Their drink, to which their customers are just as dedicated, is the Froster. Which, I'm afraid to say, looks to be another re-branded Icee, although I cannot confirm this suspicion, yet. In Canada, Mac's Convenience Stores sell the Froster.

The Slurpee, Froster, or ICEE are the true champions of the brain freeze. The Slushee could never equal the ICEE in terms of brain freeze power! All you have to do is suck down an Icee too fast and you're almost guaranteed a satisfying, and yet not so satisfying, cold headache. What's funny is we've got myths about the greatest brain freeze product ever invented, and we've got myths about the physiological origins of the brain freeze itself.

Most people realize that it has something to do with all that cold stuff hitting the roof of the mouth. But it doesn't just cause pain in the the roof of the mouth. It causes a full-blown skull exploding headache in the forehead and temple area. How? Here are some explanations. People will repeat one of these to you as if it has been rigorously proven, but…nah.

The brain freeze is caused by eating ice cream (or Slurpees) too fast in Warm weather

This is only partly wrong. I don't need to tell you it's caused by eating too fast! We all know that. The myth is that it has something to do with warm weather. That is, say, if it were 65 degrees out you'd have a hard time getting a brain freeze, and if it were winter, you couldn't get one at all. I beg to differ. Yes, you can. I know there has been some research to suggest they don't happen in the winter, but these were early studies and they were wrong. You just have to show due diligence, my friend, if you're crazy enough. Besides, this explanation is not an explanation at all, as it doesn't explain the physiological basis of the pain, and is more of a "by the way." A study by Janus Kaczorowski, and her daughter, "Ice Cream Evoked Headaches," backs me up on this, saying: "In contrast to previous studies our results suggest that ice cream headache can be induced in cold weather even in subjects who eat their ice cream at a slow pace."1

I don't know about the slow pace thing, but I'd say that is people who are a bit more sensitive, and not the norm.

The cold from the ice cream or cold drink directly cools the brain, by conduction

This is one of those really hare-brained theories. The brain is not directly affected, it's only called a 'brain freeze' because that sounds cooler than a 'cold headache'.

The Nerves in the roof of your mouth over-react to the cold and warn the brain of impending frost

This explanation says that the the cold itself causes the nerves in the roof of your mouth to "over-react" and send a message directly to the brain. The theory doesn't say why these nerves send a message to the brain, but perhaps it is to tell the brain about the cold weather in the mouth, lest it affect the brain itself. The brain then expands all the blood vessels in your head, to warm it up, so your brain doesn't freeze, you see? And this rapid dilation of the blood vessels causes the intense pain. Something just doesn't sit quite right with this. You be the judge.

The temperature sensitive nerves in your palate and throat react, and the pain in the head is referred pain

Now I think we're getting somewhere. This explanation recognizes that the temperature sensitive nerves and the "pain" nerves in this area travel the same paths. According to Migraine by Talley, et al.:

"The cold substance, which could be rocky road ice cream or a 711 slushy, provokes the sensitive temperature fibers of the second, maxillary division of the trigeminal nerve and the glossopharyngeal nerve in the throat so that certain persons develop this predictable, short lived, but disturbing experience. Pain and temperature fibers travel together through the same neuronal pathway and the "cold" can become "pain" very quickly."2

That sounds more scientific and really seems to be honing in on the thing, but it still is lacking a a bit of oomph, if you ask me. Not very satisfying at all, to us true Geeks.
I'll tell you what doesn't sit right with me, being a person who has experienced a lot of brain freezes (yep, on purpose, for science): These explanations have it that the pain is a direct result of the cold. Or, at least, a direct reaction to the cold in the mouth. Therefore, the explanations also assume that you can relieve the pain by warming the palate in some way — with your thumb, your tongue (which is presumably cold as well), warm water, etc.

Here is the problem. We are talking about a pain experience that usually doesn't last longer than about 30 seconds at the most, and then it's gone, and you're wolfing down your ice cream again. Very rarely does it last a long time, say up to 2 or 3 minutes. Finding a 'cure' for such a transient pain is pretty much impossible. See, you'll never really know if you "cured" the pain or it just ran its course. Even with variable, but short, lengths of time…it's still variable, and therefore you can't attribute the cessation of the pain, reliably, to any reaction on your part. Not only that, but you don't have to be a rocket scientist to figure out how to prevent one on your own, and most will take smaller licks from the cone, or smaller bites, or stop aiming the straw right at the roofs of their mouths and sucking too fast. The cure is prevention; you don't need a cure.

What's more, different people experience pain in different ways. How many people would intentionally bring it on, like me and my friends did? In my subjective experience, nothing had any affect on it. It just went away after a short time, on its own, regardless of what you did. Now, if warming the mouth and palate does NOT make the pain subside quicker, this lends credence to the last explanation, which I hold as the winner, for now.

The blood vessels in the roof of the mouth contract, and then quickly dilate, causing referred pain

A normal reaction to cold, is for blood vessels to restrict. So, when you stuff your face with ice cream or suck down a Slurpee too fast, the blood vessels in the roof of your mouth clamp down, as a result of signals sent by nerve clusters in that area. Then, when you remove the cold stimulus, as things start to warm up, they open back up, or dilate. The vessels dilate very quickly, in fact, to warm the area back up. This rapid blood vessel dilation causes a nerve signal which is experienced as intense pain, and this pain is referred to an area that corresponds to where the cold was applied. So, it has everything to do with the reaction of the local vessels, which referred pain elsewhere. But it's not the getting cold that causes the pain, it's the warming up. So, trying to hasten the warm up could not cure the headache! Yet, I've seen both this explanation and this cure given in the same paragraph. Doesn't make sense. If anything, it would make it worse, because the blood vessels, in response to the warmth, would just dilate their little selves like gangbusters, and you'd still have your brain freeze.3

We actually still do not really know the physiological cause of the brain freeze. That's the true explanation. We know what triggers it, but we don't know the nitty gritty of it. Only thing we can be sure of is that if you want to avoid it, don't eat your ice cream too fast, or suck down your Slurpee too fast. A few tidbits:

  • Only about one-third of people experience the brain freeze. I swear I thought it was most everybody.
  • About ninety percent of migraine sufferers are susceptible to it. However, it does not seem to be a consistent trigger for actual migraines. The literature is inconsistent, though.
  • Different names for a brain freeze are ice cream headache, Slushie headache, cold headache, cold-stimulus headache, and sphenopalatine ganglioneuralgia.
  • There have been documented cases of ice cream headaches lasting up to five minutes…ouch!

Which is more likely to cause a brain freeze: hard ice cream on a cone, or soft-serve on a cone?

That is a tough one. On one hand, soft-serve ice cream is served at a higher temperature than hard ice cream about 25°F (-4°C) as opposed to 5°F for hard ice cream. Less cold should equal less headache. However, it is easier to eat soft-serve quicker, taking huge licks of the stuff, or even biting off half of a cone at once, which I've seen some weirdos do. And it's still plenty cold enough. So I don't know, why don't you experiment with this and fill me in?

A milk shake falls somewhere in the middle, depending on how it is made. If it comes out of a soft serve dispenser, which is pretty cold, but thick, you may not be able to drink it fast enough to get a really good brain freeze. A more traditional shake tends to be a bit less cold, owing to the additional blended ingredients. Incidentally, not everybody in America calls a milk shake a milk shake. According to Richard and AnnaKate Hartell in Food Bites: The Science of the Foods We Eat, New Englanders might call it a velvet, frappe, or, in Rhode Island, a cabinet.3

The Slurpee/Frozen Margarita Connection

I don't know if you've heard, but you wouldn't be able to enjoy your frozen margarita today without the Slurpee. That's the story, anyways. It's not exactly true. To be more correct, you would not be able to enjoy them in every Mexican restaurant with consistent quality without the Slurpee. You can make a frozen Margarita just with a blender, you don't need a Slurpee machine, and I KNOW you already know that! But imagine turning out scores of perfect frozen Margaritas to hundreds of customers a night in a packed Mexican eatery. You'd have a problem with consistency and quality.

Mariano Martinez, a Dallas Mexican restaurant owner, reportedly invented the frozen Margarita in 1971, or thereabouts. It was a big hit but he had trouble keeping up with demand and couldn't always guarantee the perfect drink. Then one day he saw a 7-Eleven Slurpee machine and bingo, he had his solution. A used Slurpee machine, a chemist named John Hogan, and some tinkering, and Mariano's Hacienda was able to satisfy its customers demand for the frosty goodness that is the Frozen Margarita. Later on, specific machines were invented just for Margaritas and they are widespread in Mexican restaurants and even beyond. But Mariano's original rigged Slurpee machine is in the Smithsonian. As it should be!4

Now, I like frozen Margaritas as much as the next person. But if you've never had a Margarita and you want to know what a Margarita is like, then don't order a frozen one. Order a regular one so that you can truly experience all the flavors. Also keep in mind that frozen Margarita's will probably never use top shelf ingredients like premium Tequila and they will use a commercial "sweet and sour mix" instead of Cointreau or a good triple sec together with fresh lime juice. I think it is worth it, for your first Margarita, to go for the top shelf so that you can experience what it is meant to be like.

1. Kaczorowski, Janusz, and Maya Kaczorowski. "Ice Cream Evoked Headaches (ICE-H) Study: Randomised Trial of Accelerated versus Cautious Ice Cream Eating Regimen." British Medical Journal: BMJ 325(7378) (2002): 1445-446. Web. <>
2. Daniel, Britt Talley. Migraine. Bloomington, IN: AuthorHouse, 2010. 178-79.
3. Hartel, Richard W., and AnnaKate Hartel. Food Bites the Science of the Foods We Eat. Dordrecht: Springer, 2008. 167-69.
4. "Frozen Margaritas - Food - The Austin Chronicle." Austin News, Events, Restaurants, Music. Web. 24 Mar. 2012. <>.
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