A Rainbow Belt is a flat gummy ribbon, usually around 2cm wide, coated in a layer of sour sugar crystals that hits your tongue before the fruit flavour underneath does.
From fruit rope to sour belt
Flat gummy ribbons grew out of the licorice-rope and fruit-roll formats that American candy makers scaled up through the 1980s and 1990s. As the "extreme sour" trend took hold, manufacturers started dusting those same ribbons with acid coatings instead of leaving them plain — and the belt format proved better suited to holding an even coating than a rounded rope or worm shape.
The science behind the sour kick
The sourness comes from citric and malic acid dusted onto the ribbon while it's still warm and slightly tacky from the gummy-forming process. The acid crystallises into the surface as it cools, so the sour hit arrives in the first bite rather than being mixed evenly through the whole piece.
Belts vs. laces vs. ropes
- Belts — wide, flat ribbons, usually cut to a set length and often striped in rainbow colours.
- Laces — narrower and thinner, closer to a shoelace in profile.
- Ropes/worms — rounded rather than flat, with less surface area to hold a sour coating.
Find more sharp-flavoured options in our sour sweets collection, including gummy ribbons from Vidal.
Frequently asked questions
What are Rainbow Belts made from?
They're a gelatine-and-pectin gummy base, formed into flat ribbons roughly 2cm wide, then coated in a dusting of sour sugar crystals while still tacky.
Why are they called belts?
The name describes the format — a flat, ribbon-like strip rather than a rope, worm or drop shape — distinguishing it from other gummy candy styles on the same shelf.
What makes Rainbow Belts sour?
A mix of citric and malic acid is dusted onto the warm gummy ribbon so it crystallises into the surface, delivering a sharp hit before the underlying fruit flavour comes through.