Mixers

Caster Sugar

Caster sugar is white sugar with a fine grain, about a third of a millimetre, sold in the United States as superfine sugar. The small crystal dissolves far faster than granulated, so it is the sugar to use dry in a drink. Our Daiquiri stirs two bar spoons into the rum and lime, the Caipirinha muddles four teaspoons onto lime, and the Lemon Drop wears it on the rim.

Quick Facts

Legal categoryFood

Flavour Strengthlight

Our keeping timeIndefinitely, airtight and dry.

Storage

Airtight and dry. A fine grain takes up moisture and clumps faster than granulated.

Allergens

None of the 14 listed allergens.

The ingredient

About Caster Sugar

Flavour Profile

Primary Flavours

clean sweetnessneutral

Tasting Notes

Clean, neutral sweetness with no colour and no aftertaste: sugar doing only its one job, sweetening a drink without flavouring it.

The same sugar, a finer grain

Caster sugar is refined white sugar, beet or cane, with a crystal of about 0.35mm. Americans call it superfine. Nothing is added; the smaller grain gives more surface to the liquid, so it dissolves in a cold drink in seconds where granulated lingers. That speed is the only reason to keep it behind the bar. Once dissolved, caster and granulated sweeten identically, weight for weight.

White sugars by grain, from coarse to fine

Granulated

Grain: Medium crystal
US name: Granulated
Dissolves in a cold drink: Slowly
Added to it: Nothing

Caster

Grain: About 0.35mm
US name: Superfine
Dissolves in a cold drink: With a short stir or muddle
Added to it: Nothing

Icing

Grain: Powder
US name: Powdered, confectioners’
Dissolves in a cold drink: On contact
Added to it: Anti-caking agent

Sugar	Grain	US name	Dissolves in a cold drink	Added to it
Granulated	Medium crystal	Granulated	Slowly	Nothing
Caster	About 0.35mm	Superfine	With a short stir or muddle	Nothing
Icing	Powder	Powdered, confectioners’	On contact	Anti-caking agent

Stirred, muddled or on the rim

The Daiquiri stirs two bar spoons into the rum and lime until they dissolve, then shakes. The Caipirinha muddles four teaspoons onto lime for 20 to 30 seconds, the grains scouring oil from the peel. The Mojito presses two teaspoons of white cane sugar with mint, and the Lemon Drop Martini rolls half its rim through caster.

Fine sugar for any dry sweetening

Wherever a recipe sweetens with dry sugar, caster is the safe choice: a teaspoon shaken hard with wine and citrus, a crust on a rim, sugar muddled with fruit. For everything else, simple syrup at 1:1 by weight measures more evenly, and caster makes that syrup a little faster. For cubes see granulated sugar; for the powder in a Julep, powdered sugar.

Using it

Using Caster Sugar

Usage

Stirred into rum and lime until dissolved before shaking, as in our Daiquiri; muddled onto lime wedges for a Caipirinha; or rolled onto a wet rim. For anything else, simple syrup measures more evenly.

Pro Tip

In a Daiquiri made with caster, check the bottom of the tin before adding ice. Grains left there mean the drink will be sharper than the spec.

Top Tips

Stir caster into the spirit and juice until it has dissolved before any ice goes in.
For a rim, wet only the outside edge with lemon so the sugar stays off the inside of the glass.
Keep it airtight. A fine sugar takes up damp and clumps faster than granulated.
No caster? A few seconds in a spice grinder turns granulated into a workable substitute.

Possible Substitutions

Sugar (Granulated): given longer to dissolve, or blitzed finer
Simple Syrup: already dissolved
Powdered Sugar: at a lighter hand: sweeter by volume

Production Method

Refined white sugar, from beet or cane, sieved or milled to a fine crystal of about 0.35mm: finer than granulated, coarser than icing sugar.

Go further

More to explore

Common Questions

What is caster sugar?

White sugar with a fine crystal, about 0.35mm, between granulated and icing sugar. It is the same sucrose as granulated, from beet or cane, and tastes the same; the small grain simply dissolves much faster, which is why it is the sugar for drinks sweetened dry.

Is caster sugar the same as superfine sugar?

Yes. Superfine is the American name for caster sugar, and in Canada it is sold as berry sugar. Icing sugar, called powdered or confectioners’ sugar in the US, is a different product: milled to a powder, with a little anti-caking agent mixed in.

Why does the Daiquiri use caster sugar instead of syrup?

The IBA recipe specifies sugar, and caster dissolves in rum and lime with a short stir. Without the water a syrup brings, the drink stays a touch stronger and sharper. Our recipe stirs two bar spoons in until dissolved, then shakes hard with ice for 10 to 12 seconds.

How do you sugar the rim of a Lemon Drop?

Run a lemon wedge around the outside of half the rim of a chilled coupe, then roll that half through caster sugar on a plate. Half a rim lets the drinker choose each sip. Caster gives an even, fine crust that granulated cannot.

Can I use granulated sugar instead of caster?

In a Caipirinha or Mojito, yes, with more muddling or stirring. In a Daiquiri, granulated may not dissolve fully before the ice goes in. Grinding granulated for a few seconds makes a workable caster; a 1:1 simple syrup by weight is the other route.

How much caster sugar goes in a Caipirinha?

Our recipe puts four teaspoons over the lime wedges and muddles firmly for 20 to 30 seconds, until the lime has given its juice and the sugar has begun to dissolve. The grains also scour the peel, drawing out its oil.

Does caster sugar go off?

No. Sugar is too dry for microbes to grow in, so sealed caster keeps indefinitely. The risk is damp: the fine grain soaks up moisture and sets into lumps. Keep it airtight and away from steam, and break up any clumps before measuring.

Make something

Made with Caster Sugar

Featured In These Cocktails

Daiquiri Mojito Caipirinha Lemon Drop Martini Sherry Cobbler Brandy Crusta

Often Used With

Guide by Jerry Can Spirits · Updated 11 October 2026

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