Ice cream spiders and floats: a Kiwi classic

An ice cream spider is the Kiwi name for an ice cream float: a scoop of ice cream dropped into a glass of fizzy drink so it foams up into a creamy, bubbly head. To make one, fill a tall chilled glass about two-thirds full with a cold soft drink, slide in one or two scoops of vanilla ice cream, then top up slowly down the side of the glass. Serve it straight away with a long spoon and a straw. Here is where the name comes from, why it foams, and how to stop it spilling.

What is an ice cream spider?

A spider is simply a float by another name, used in New Zealand and Australia. According to Wikipedia's ice cream float article, the name comes from the look of the drink: once the bubbles hit the ice cream, the foam spreads out in a pattern a bit like a spider's web. The same article says spiders are traditionally made with lime or pink cream soda.

Elsewhere it goes by plenty of other names. Americans talk about ice cream sodas and root beer floats, and a root beer float is sometimes called a black cow or brown cow. In the UK and Ireland it is usually just a "float", because "soda" there tends to mean soda water.

The drink has a long history. Wikipedia credits Robert M. Green with serving vanilla ice cream in soda in Philadelphia in 1874, while noting that several other people also claimed to have invented it.

Why does a spider foam up?

The fizz and the ice cream work together. The soft drink is full of dissolved carbon dioxide, and when it meets the ice cream, bubbles are released fast. The ice cream also has tiny air bubbles of its own folded through it.

Wonderopolis explains that the fat in ice cream coats those bubbles and protects them, so instead of popping straight away they build up into a thick, creamy foam. That is why a spider makes far more froth than a fizzy drink poured over ice cubes.

Rough surfaces help bubbles form, too. The Naked Scientists describe how the tiny cracks on an ice cube give carbon dioxide somewhere to gather, which is why a drink can fizz over the moment the ice goes in. A scoop of ice cream, with its uneven, crumbly surface, gives the bubbles lots of places to start.

How to make a spider that doesn't overflow

Chill everything, pour slowly, and add the drink in two goes. The foam settles if you give it a few seconds between pours.

You'll need

• A tall glass, chilled in the freezer for 10 minutes
• About 250 ml cold soft drink, straight from the fridge
• 1–2 scoops of ice cream (vanilla is the classic)
• A long spoon and a wide straw

Method

1. Pour first, scoop second. Fill the glass about halfway with the soft drink, tilting it as you pour so the bubbles stay in the drink.
2. Slide in the ice cream. Lower the scoop gently onto the surface instead of dropping it from a height. Expect a burst of foam.
3. Wait. Give it 10–20 seconds for the foam to calm down.
4. Top up slowly. Pour the rest down the side of the glass, a little at a time, stopping when the foam reaches the rim.
5. Serve straight away. The bubbles fade within minutes, and the ice cream keeps melting into the drink.
6. Ice cream first instead? You get a wilder head, but it overflows easily. Do it over the sink.

A slightly soft scoop sits more neatly than a rock-hard one. Our guide to softening ice cream shows how to get it scoopable without the edges turning to soup.

Spider and float flavour pairings

Pick a soft drink and an ice cream that would taste good side by side. Vanilla goes with almost everything; bolder flavours work best with a matching drink.

If you want something coffee-based but warm, an affogato is the same idea with hot espresso instead of fizz. And if a spider is too light for you, a proper Kiwi thickshake is its thicker, creamier cousin.

Ice creams with chunks, ripples and swirls can be fun in a spider, though the pieces tend to sink. Have a look at our flavours for ideas, and serve chunky ones with a spoon.

Dairy-free and lower-sugar spiders

Swap the ice cream and the drink, and the method stays the same. A dairy-free scoop works fine, and a diet soft drink cuts down the sugar.

• Dairy-free: use a plant-based ice cream such as our oat milk dairy-free range. Expect a slightly different foam, since the fat comes from a different base. Our post on dairy-free ice cream explains how the bases differ.
• Less sugar: try sparkling water with a squeeze of lime or a splash of fruit juice instead of a full-sugar soft drink. It is less sweet but still fizzy and refreshing.
• Smaller serves: a half-size glass with one small scoop is plenty for younger kids.

Allergy and safety notes

Check the labels on both the ice cream and the drink. Most of the allergens in a spider come from the ice cream and any toppings.

• Milk is in regular ice cream. Use a dairy-free one for anyone who can't have it, and wash scoops between tubs.
• Nuts, eggs, soy and gluten can turn up in mix-ins, cones and toppings. Our ice cream allergens guide and the ingredients and allergens list help you check.
• Caffeine: cola, some energy-style drinks and coffee versions contain caffeine, which is worth keeping in mind for kids' parties.
• Go slow: a very cold spider sipped quickly through a straw is a reliable way to set off brain freeze.

Serving spiders at a party

Set up a spider station and let people build their own. It is cheap, quick and keeps everyone busy.

• Keep the soft drinks in a chilly bin of ice, and the ice cream in the freezer until the last moment.
• Pre-scoop balls of ice cream onto a lined tray and freeze them for 30 minutes so serving is fast.
• Put the glasses on trays to catch any overflow.
• Label the drinks and ice creams, especially any dairy-free or caffeine-free options.

For bigger gatherings, our guide to how much ice cream to buy for a party helps with quantities, and a spider station sits nicely beside an ice cream sundae bar.

Quick spider checklist

• Glass chilled; soft drink fridge-cold.
• Drink in first, tilted pour.
• Scoop lowered gently, not dropped.
• Pause for the foam, then top up slowly.
• Tray or sink underneath, just in case.
• Labels checked for allergens and caffeine.

A spider takes two minutes and two ingredients, and it still feels like a treat. For more ideas, our FAQs cover the basics, and for the latest on where to find our tubs this summer, follow us on Instagram and Facebook.