If you've just bought a slush machine, or you’re eyeing one up, there's a good chance you'd like to know the key slush ingredients that go into it. As if you get the ingredients right you'll enjoy a smooth, refreshing ice-cold drink, but get them wrong and you'll either end up with a solid block of flavoured ice, or a sad, watery puddle!
So let's have a proper look at what goes into a slush machine, what slush syrup is made from, and what to do if you'd rather leave a certain ingredient out altogether.
The basic ingredients of a slush syrup mix
At its core, a slush drink is made from three things: water, sugar and flavouring.
That's genuinely it. Just water, sugar and something to make it taste like those nostalgic flavours you remember savouring as a child.
The sugar and water form a syrup base, and that syrup is what gets churned in the machine at a low temperature until it turns into that familiar semi frozen slush texture.
The reason you can't just chuck plain water in and hope for the best is that plain water freezes solid. So slush machines rely on sugar to lower the freezing point of the mixture, which is what keeps it soft and scoopable rather than turning into an ice cube.
The trick behind great slushies comes down to the ratio of flavoured sugar mix to water. Too much and it never freezes properly. Too little and you’ll need to chisel it out.
What's in slush syrup?
Shop bought slush syrup usually contains a handful of standard ingredients…
- Water and sugar, which make up the bulk of the mixture and give it the right consistency
- Flavourings, either natural or artificial
- Colourings, to give you that bright blue, red or green that makes a slush look like it belongs in a cartoon rather than a cup
- Citric acid, which adds a bit of tang and helps balance out all that sweetness
- Preservatives, to keep the syrup stable once it's opened
- Historically, Glycerol, which many syrups include to help control the freezing process and give a smoother finish
Glycerol used in slush syrup
Glycerol has traditionally been a common ingredient in slush syrup because it helps the mixture stay slushy rather than icy, stopping the drink from separating or forming ice crystals. It's been used in the industry for years and does the job well, which is exactly why you'll still find it in a lot of syrups today, including several of ours.
The one thing worth knowing is that the Food Standards Agency has advised that young children shouldn't drink more than one slush a day, and that under-7s should avoid glycerol-based slush altogether, since drinking a lot in a short space of time can cause headaches or nausea. For most people, enjoyed sensibly, glycerol slush is perfectly fine. But it's understandable that some parents, venues and event organisers would rather sidestep the question entirely.
That's where our glycerol free syrup range comes in. Manufacturers such as ourselves are now able to provide that proper slush consistency without it, using shorter, simpler ingredient lists.
Can you use squash or fizzy drinks instead?
Technically, yes. You could pour squash or a can of fizzy pop into a slush machine and see what happens…
Whether you should is a different question entirely.
Ordinary squash or fizzy drinks aren't designed with the right sugar concentration for a slush machine, so you'll often end up with something too icy, too watery, or you could well damage the machine with long-term use.
Proper slush syrup is formulated specifically to hit that sweet spot between sugar and water, which is why it gives such a reliable result compared to homemade alternatives.
Fizzy drinks bring their own extra complication too, since the carbonation tends to behave oddly once it's being churned and chilled, and without supplementation, you can end up with a machine full of foam.
The syrup you choose matters
It's tempting to think one syrup is much the same as another, but the syrup you choose really does make the biggest difference to how your slush turns out. A good quality syrup will be formulated to give a consistent freeze, a decent shelf-life once opened, and flavour that doesn't fade.
Cheap or poorly made syrups can let you down in a few classic ways. Sometimes the drink refuses to freeze properly no matter how long you leave the machine running. Other times it freezes too hard and turns into a single solid mass. Neither of these is much fun when you've got a queue of thirsty guests.
Whether you go for a traditional syrup with glycerol or one of the glycerol-free options, the key is picking something made specifically for commercial slush machines rather than trying to improvise or cheap-out.
It'll give you a far better drink at the end of it, and frankly, a better reputation as the person serving delicious slushies.
A few top tips
Once you've got your ingredients sorted, a few small habits go a long way…
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Always follow the mixing ratio on the syrup bottle rather than eyeballing it, since slush machines are less forgiving than a cup of squash and more precise than you might expect from a machine that mostly just spins in circles.
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Give the machine time to properly chill and thicken the mixture before you start serving, since impatience is the number one cause of disappointingly liquid slush.
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Give the machine a proper clean in between switching flavours and as part of your regular upkeep to keep it running smoothly.
Syrup storage and shelf life
Most syrups will keep well for a while once opened, provided they're stored somewhere cool and out of direct sunlight, but always check the label rather than trusting your own judgement.
Unopened bottles have a longer shelf life, which varies by manufacturer. So it's perfectly sensible to keep a stock in the storage room ready.