The History and Science of Frozen Slushie Cocktails
Every time I've come across premade frozen-cocktails-in-a-bag at the grocery store, I can't help but wonder if there might be something worth drinking inside.
But, first I had to establish a baseline for my expectations. What defines a 'good' frozen cocktail? Does such a thing exist? How did these cocktail-pouches come to be? The history is a little more extensive than you might suspect.
It Began With Shaved Ice...
If you've ever visited East Asia or frequented a decent Chinatown in another country, you've probably come across some version of shaved ice. In China, it's known as "bao bing," in Korea "bing soo" and in Japan, it's called "kakigori," but the basic concept is the same: take a large chunk of ice, shave tiny flakes off from it, and flavor with sweet toppings.
Versions of shaved ice have been eaten in Asia since as early as the 7th century A.D. As technology has progressed, the texture of the shaved ice has become increasingly more fine and creamy. Today, condensed milk is considered a 'traditional' topping for shaved ice, though it seems that the addition of milk is quite new: condensed and evaporated milks weren't even invented until the mid-1800s. Regardless of culture, creaminess seems to be a desired trait in the ice-based cocktail category.
When I dug into the history of slushie type drinks in the United States, I discovered that the turning point that created Americans' love affair with frozen drinks took place somewhere around the 1950s.
Why then? To simplify: World War II changed the priorities of the American household. During the war, women had to take jobs outside the home, and when the war ended, many women wanted to keep those jobs and sought out convenient tools and technology to make housework lighter. With a booming economy, consumerism was on the rise.
1930s-1950s: Enter the Blender
The electric blender had been around as early as the 1920s, but at first it was considered a large, loud, dangerous device better suited to medical research than home cooking. By the 1950s, though, the blender had gone through several redesigns and was considered a useful kitchen tool.
In 1938, Fred Waring, the blender's original inventor, brought his contraption to a famed home economist named Mabel Stegner. In 1952, Stegner released a book titled "electric blender recipes," and in this book is the earliest published mention of the blended strawberry daiquiri that I have been able to find.
Unlike the classic rum daiquiri which is a simple and tart mix of rum shaken with sugar and lime, the strawberry daiquiri relies on the electric blender to pulverize frozen strawberries (another convenience born around the same time) into a syrupy, slushy mess. Love it or hate it, the strawberry daiquiri would live on to be the great-grandparent of all manner of blended cocktail.
1970s: Making Margaritas Easier
Rayna Green helped curate the recent food exhibit at the National Museum of American History in Washington, DC. In this excellent article for the Atlantic Monthly, Green explains how in the process of her research, she came upon the world's first Margarita machine.
I won't give all the details from the article away, but essentially frozen margaritas became popular around the same time as strawberry daiquiris did, but it was a pain to keep blending these drinks for service in bars. So an enterprising entrepreneur teamed up with a chemist to hack a soft-serve ice cream machine to dose out always-ready Margarita slush.
I bet the Margarita machine's original creators used quality tequila and lime, but they did have to add extra sugar to the machine to get the consistency right, and this simple change could be what was ultimately responsible for decades of terribly sweet blended cocktails.
The Modern Pre-Made Boozy Slushie
Let's fast forward a bit. We all know that for the last few decades, plenty of pre-made bottled drink mixes have come and gone, and many of those were glow-in-the-dark toothachingly sweet syrups designed to be blended with ice and alcohol. Frozen drinks earned a bad reputation over the years, especially as the cocktail renaissance began to praise the value of freshly squeezed juices and high-quality spirits in cocktails.
So why is it that I've started noticing a resurgence of pre-made slushie drinks at the grocery store? Are these things any good? I made a few purchases in the name of science.
These concoctions come in a variety of flavors and I've seen them sold both frozen and on the shelf, in liquid form. The instructions on the bag say to freeze the contents for at least 8 hours. In my freezer, that turned the drink into a solid block of ice.
But it was easily fixed by a quick run under warm water...
...and some gentle massaging.
You'll know when the texture is about right—the contents in the bag will flow around smoothly, and will feel like a thick liquid, not a chunk of ice. The drink pours smoothly from the bag.
And, depending on the particular flavor, the ice stays soft, thick, and reasonably creamy for a long time.
So, how are they? They tasted...well, not worth tasting. I purchased 5 different flavors to see whether ingredients and textures varied. The pina colada had the best creamy texture, but there wasn't even the slightest hint of rum flavor. The 'frozen wine cocktails' by Arbor Mist had the best flavor, probably because they actually tasted like wine, but even so, they were sugary to the point that I couldn't finish a whole pouch.
What We Can Learn From Bagged Drinks
Someone is buying these drinks, for sure, and manufacturers seem to have hit a sweet spot of convenience, since there's no need to put syrup + ice in a blender anymore. The flavor isn't great, but I have to give whoever conceived the things props for being able to create consistently-textured results with zero stirring or blending.
The next natural question (at least for a curious person like me) then becomes: can we improve the texture of homemade frozen cocktails using tricks we learned from the big brands? To find out, let's start by taking a look at the ingredients list:
Here's my breakdown, to explain what's going on:
- The basics. Water and wine. Alcohol does help to lower the freezing point of ice and therefore give drinks more of a "slush" texture, but in the low amounts found in these products, the effect will not be significant.
- Flavorings. High fructose corn syrup, natural flavors, pear juice concentrate, citric acid, sucralose. You might know sucralose better by its brand name Splenda.
- Preservatives. Sodium benzoate and potassium sorbate: these are widely used in industry and are recognized as some of the least toxic preservatives available.
- Texture agents. Here's where it gets interesting. Glycerin is a sugar alcohol (polyol) that binds water. In this application, it's probably one of the keys to why the cocktail doesn't separate when frozen. Xanthan gum is another important thickener (it's also known for being the secret behind blended coffee drinks).
- Emulsifiers. Gum arabic and medium chain triglycerides (MCTs) help flavoring agents stay evenly dispersed within a liquid. That's because many flavorings are more soluble in oil than in water and so would separate without the help of these emulsifiers. Gum arabic has also been shown to prevent the formulation of large ice crystals, which could contribute to a more creamy texture, but I'm not sure they're if they're using enough of it here to make a difference.
- Not sure. Sodium polyphosphates are a name used for a few different types of salts that can help other salts stay in solution. It has many uses in food processing, but I think it's most likely being used here in conjunction with the MCTs as an emulsifier—but I can't be sure. Then there's carbonated water: that one throws me for a loop. I have no idea why carbonated water would be used here, especially in small amounts. If you have an idea, please leave a note in the comments.
What have we learned? There sure was a lot of technical wizardry involved in creating the desired texture in these cocktails, but was any of it really necessary? I don't think so.
When I researched this more, I found out it's not that hard to make frozen drinks ahead of time. As it turns out, real fruit, either fresh or frozen, does double duty as both thickener and emulsifier. Fruit makes a decent flavoring agent, too.
So if blended slushie cocktails are one of your dirty pleasures, don't be ashamed to whip one up as the weather gets warmer (or as you try to pretend that you're escaping to a tropical destination). Simply get your hands on a good blender and try one of these solid (or not so solid?) recipes.
What are some of your favorite frozen blender drinks?
About the author:Kevin Liu likes to drink science and study cocktails. Wait, that's backward. Ask him geeky food and booze questions on twitter @kevinkliu. While you're at it, check out his book about cocktail science.