How to Use a Slushie Machine

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Slushy Machine

The newly rediscovered interest in slushy cocktails has resulted in me being inundated with questions about how to properly operate a slushie machine. And so, as has always been my mission with this website, I’m here to try to help. You see, for the longest time operating a slushy machine was a lengthy experiment every time I attempted it. My process typically looked like this:

  1. Make a big batch of cocktails.
  2. Adjust the recipe to taste.
  3. Pour it into a slushy machine.
  4. Wait many, many, many hours for it to get cold enough and hope the texture was right, fingers crossed.
  5. The texture isn’t right. Shit.
  6. Try adding some more water. Now we need to get it back down to the right temperature. Wait an hour.
  7. That made it too watery. Try adding some simple syrup. Wait another hour.
  8. That seems better. But it’s still kinda chunky-looking.
  9. Add some alcohol. Wait another hour.
  10. Okay, now it tastes too strong. Maybe if I add a little more simple syrup, a splash of water, and a little juice. Wait an hour.
  11. That kind of seems to be working, but now I’m a little drunk from tasting this thing ten times.
  12. Oh, the event is starting in ten minutes.
  13. Good enough, I guess.

Obviously that’s a lot of steps, and way too much trial and error to make it a feasible thing to do regularly. But there has to be some sort of formula, right? Well, I did some research, and it gets really confusing, really quickly. There are formulas, there are opinions, there are arguments online, and there is a whole lot of puzzling contradictory info.

I talked to bartenders, and they’re even confusing. There are some who claim to be experts, but after some gentle prodding you discover they’re using the trial and error method I was trying to avoid. And finally I found someone who knows what he’s talking about, my good friend Cameron Bogue. You see, Cameron oversees a shit-ton of slushy machines at the massive restaurant group in Canada he works for. And he told me exactly what you need in order make your slushy drink work. Ready?

It needs to be between 13 and 15 Brix.

And that’s pretty much it. Brix is the unit of measurement of sugar in a water solution. One brix is equal to a gram of sucrose per 100 grams of solution. And, of course, there’s a whole lot of other complicated shit that you can read about that goes along with the topic, but as someone who’s going to put a Daiquiri in a slushy machine, all you need to know is that your Daiquiri needs to be between 13 and 15 Brix.

And how do you figure that part out? Easy. First off, go get yourself a portable refractometer. They’re cheap, and they’re actually kind of fun to use. Once you’ve received your one piece of specialty equipment in the mail (uh, yeah, other than the slushy machine, I guess) then you’re ready to whip up a batch of frozen cocktails with no trial-and-error required.

First, figure out your recipe. You can do this by using the methods I outline in Chapter 9 in my book (shameless plug), or you can throw caution to the wind and just do it to taste. I’ve done it both ways for use in slushy machines and it does not matter. The only two things that matter are that the drink taste good, and that the sugar content is between 13 and 15 Brix.

Next, you need to dilute the drink a little. Drinks are pretty rough at full strength, and you’re likely going to have to do it anyway once you start checking the brix, so go ahead and throw some water in there. I like to start with 20%. Want an easy way to do that? Figure out the volume of your cocktail (real easy to do if you’ve got it in a big measuring container) and multiply by .2 – That’s the amount of water you’re gonna want to add.

Okay, now the fun part. Take the pipette that came with your refractometer and grab a few drops of that cocktail of yours. Put it on the glass and close the slide cover.Hold the refractometer under a light and look through the lens. Read the total brix.

Now this is where you’ll make adjustments. Honestly, if the drink tastes balanced, it’s probably pretty damn close. If it’s not, well, maybe making balanced drinks isn’t your strong suit. That’s okay, we’ll fix that now.

Brix number too high? Just add a little water to the mix, a bit at a time, until you come in between 13 and 15 Brix. (Don’t forget to stir.) Brix number too low? Add some simple syrup, a little at a time, until you come in between 13 and 15 Brix. This is what you’ll see when you look through that refractometer, by the way:

I like to chill the mixture overnight, if I can. Getting it as cold as possible means it will take less time to come to temperature once you pour it in the machine, but if you can’t do that, it won’t negatively affect the taste or texture of the drink, it’ll just take longer to coldify. Once you’re ready, pour it in the machine and turn the machine on. This takes a couple of hours, at least. But once it’s nice and cold, you will have a perfectly slushy cocktail, provided you got it between 13 and 15 Brix. Your drink will look like this and you will be something of a hero.

And that’s pretty much it! A few notes, just off the top of my head:

  1. Yes, I’m aware that straight vodka does come in between 13 and 15 Brix. Alcohol does register as sugar on the portable refractometer. Bear in mind that I’ve never tried dumping straight vodka into a slushie machine to see if it would slush. Someone please report back and let me know if it works.
  2. Sours are the best drinks to experiment with at first. So, Margaritas, Daiquiris, Sidecars, etc. They’re basically built to come in at the right Brix number already. Once you’ve gotten a feel for making slushy sours, then I would recommend experimenting with the trickier slushy drinks, like Manhattans, etc.
  3. I know lots of you have been wanting a slushy Negroni recipe. Sadly I no longer have my notes from the last time I did that a few years ago, but here is the version I make in a blender at home. Feel free to scale it up and adjust for Brix.

Have fun!!

35 Replies to “How to Use a Slushie Machine”

  • Scott says:

    @ Kern:

    I did a frose experiment a few months back. For a 750 ml bottle of cheap $10 rose, 50 grams of caster sugar should dissolve right in the cold wine. I didn’t test it in a slush machine, but it was pretty good when I tried a scaled down sample (150 ml wine w/ 5 gm caster sugar, mixed up and left to freeze).

    This should be fine in a machine but i haven’t tested it, so if it gets too hard, make sure you have some simple syrup on hand to adjust it.

    On the other hand I avoided simple in this recipe because it kept watering down the slush, so you might want to avoid the syrup.

  • Jason says:


    I’ve been working on an orange creamsicle slushie for a friend’s wedding. I plan on adding moonshine to it:) This weekend i made this recipe for an Orange Julius,, it came out awesome! I was adding vodka to it after i poured it, because wife and kids were drinking it also. I ended up multiplying everything by 16, and added 1/2 gallon of water. I initially added a quart of water, but added more because of the sweetness. This is a winner. BTW I’m using a Ugolini NHT 2UL.

  • belinda says:

    Good Froze recipe
    1 750 ml bottle hearty, bold rosé (such as a Pinot Noir or Merlot rosé)

    ½ cup sugar

    8 ounces strawberries, hulled, quartered

    2½ ounces fresh lemon juice

  • charlice says:

    I am absolutely, 100% positive that none of your machines are that intelligent that it will measure your electrical circuit and then as a nice little machine only use whatever is left over so that the fuse won’t burn up, or break off the power if you have modern ones.

  • Seege says:

    Is it just me or has anyone noticed that if you put liquor in a slushy machine the alcohol evaporates over time. Am I crazy or is this actually happening?

  • This is wrong because both alcohol and sugar refract light. It works only by coincidence, because it just so happens that a palatable drink is right around the slush range. I would say that if you got better at making them, it was more from experience than use of a refractometer because you are using the refractometer in a way that can not produce reliable results.

    A refractometer doesn’t measure sugar. It measures refraction. And then you use the refraction to figure out the amount of sugar because there is a known relationship. Instead of displaying the index of refraction on the refractometer, it’s marked as percent sugar (brix) because that’s what you need to know.

    The best analogy I can give is your car’s odometer. Your car’s odometer shows you miles, but it doesn’t actually measure miles. It measure’s a wheel’s rotation. But it knows x rotations = 1 mile, and you don’t give a shit about rotations. So the meter shows you miles. However if your car’s wheels are rotating without you moving (for instance your car is on rollers for an e-check) you get FUD from the odometer because what it’s actually measuring isn’t what it’s displaying.

    Refractometers work the same. There are refractometers for other things, that are the exact same device but with different markings to show you different things for different refractive indexes. An alcohol refractometer might be the exact same as that sugar one, but have markings for ABV instead.

    The problem is a refractometer does not work properly when there are two refractive substances, because they both refract light differently. That 13 brix you’re seeing isn’t actually 13 brix. It’s more like “if there were just sugar in here, the refractive index would indicate 13 brix” But there isn’t just sugar. Worse yet, it’s really hard to establish any linear relationship between them. There are a million different combinations of ABV and brix that might make your refractometer say “15 brix” and many of them would not form a slush.

    (Also no, vodka would not slush in one of those machines. If something won’t turn to slush in your freezer, it won’t there because they aren’t colder. You’d have to get much lower temp, like with dry ice, to get it to slush. Vodka has no sugar, it just apparently has the same refractive index as a 13% sugar solution. That’s just coincidence.)

    If you want to actually measure the brix of your cocktail, the easiest way is to use a spreadsheet. Use the refractometer to take anything that has sugar in it (fruit puree, for instance) and find it’s brix. Water, liquor, etc. have no sugar. (Liqueurs are tricky because they have sugar and alcohol, but you can Google the brix of most of them, or look them up in Liquid Intelligence, and of course they say the ABV on the bottle. You cannot find their brix via refractometer, even given the ABV, because the refractive index doesn’t change in a predictable way.)

    Take a slushy from 7-11 and put it in the refractometer and you’ll see it’s actually about 12 brix. This is actually just a hair more than Coke and Pepsi, which is why they slush up nicely with a tiny amount of sugar added. You taste the sugar less when they’re cold, so it tastes about the same.

    You actually only need about 12% brix to slush. (I’d not be surprised if slushies have some hydrocolloids for texture but if they do I don’t know what.) However you could easily go as high as 20% sugar and still get a slush. (Sorbet has about 30% sugar, for comparison.)

    Ethanol also lowers the freezing point, so by adding liquor you can dial down the sugar. If you’re getting your drink coming out too loose, you’ve probably got too much liquor. (If it’s too much sugar it will be unpalatable.) If it’s too solid, you can dial up the liquor and/or sugar.

    Again, the best way is to design in a spreadsheet. I’m happy to share mine.

    • Jeffrey Morgenthaler says:

      This is super helpful and makes a ton of sense. I think we’d all love to see that spreadsheet if you wouldn’t mind sharing it!

  • Sure, here’s one I did for a recent cocktail. You should be able to download it and use it yourself. With a little Excel-fu you could switch it match cocktails with other ingredients, this is pretty much basically a sour with fruit puree.

    I like generally around 13-15% sugar and around 1% acid. (This measures that too, lemon and lime average around 6%. You can get an acid titration test kit for cheap from a homebrew store if you want to measure other purees but I usually just Google the titratable acidity of whatever fruit and assume it’s close enough.)

    I do small batch scaling on the right and the whole scaling on the bottom because I might make 20 gallons at a time and have to break it down into several buckets. The bottom part is mostly for purposes of my shopping list.

    Hope this helps.!AoMxtSMowPvuwEGiuIFzvKZYPRcR

    • Jeffrey Morgenthaler says:

      Thank you, Matthew! This is incredibly helpful!

    • Ryan Autry says:

      Matthew! This is incredible information. I just stumbled upon this as I am researching into doing frozen cocktails for my bar program. I downloaded your spreadsheet and have some questions in regards to the breakdown. Would there be a way to connect with you and pick your brain on the subject?

  • Charlice says:

    Hey Jeffrey, thank you for this tutorial.

    I know a slushie machine is a nice little tool to have but I always look at the price tag. Do you think this can be a good investment if you are not buying it to use in a shop? I’m also thinking of getting a freezer but I’m sure I can make a slushy drink with that. What do you think?

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