Both get called the "chunky" chocolate bars on a UK shelf, but they're chunky in completely different ways. One is just a thicker piece of plain chocolate; the other is a filled bar stacking caramel and biscuit inside the shell.
Yorkie: chunk is the whole idea
Rowntree's launched Yorkie in 1976 specifically to compete with Cadbury Dairy Milk by being thicker and more deliberately "manly" in its marketing - the famous trucker-themed adverts ran until 1992. There's no filling: it's solid milk chocolate moulded into deep rectangular chunks you snap off one at a time. The bulk comes purely from the depth of the chocolate itself. It's made by Nestle now, still produced at the original York factory the bar is named after.
Boost: chunky because of what's inside
Cadbury launched Boost in 1985 as Coconut Boost, a coconut-and-caramel bar, before reworking it into the caramel-and-biscuit version sold today. A Boost bar is milk chocolate wrapped around a crunchy biscuit centre and a layer of chewy caramel, so its heft comes from what's stacked inside rather than a thick slab of chocolate. Bite into one and you get three textures - chocolate, caramel, biscuit - rather than one.
Which one's "chunkier"?
It depends what you mean by chunky. Yorkie wins on raw chocolate depth - there's simply more solid chocolate per chunk. Boost wins on how much is going on in each bite, thanks to the biscuit-and-caramel filling. Neither is the bigger bar by weight; they're chunky on different axes entirely.
What we stock
We carry Yorkie Milk Chocolate Bar 46g, Yorkie Milk Chocolate Duo Bar 72g and Yorkie Raisin & Biscuit Bar 44g, alongside Cadbury Boost Chocolate Bar 48.5g and the Cadbury Boost 4 Pack Multipack 126g.
Frequently asked questions
What's the difference between Yorkie and Boost?
Yorkie is solid milk chocolate moulded into thick, deep chunks with nothing inside. Boost is a filled bar - a crunchy biscuit centre wrapped in chewy caramel, coated in milk chocolate - so it's chunky because of what's packed inside it, not because the chocolate itself is thicker.
When was Yorkie launched?
Rowntree's launched Yorkie in 1976, pitched as a chunkier, more filling alternative to Cadbury Dairy Milk. It's made by Nestle today, still at the original York factory.
When was Boost launched?
Cadbury launched it in 1985 as Coconut Boost, a coconut-and-caramel bar. It was later reformulated into the caramel-and-biscuit bar sold today under the simpler Boost name.
Does Supreme Sweets stock both?
Yes - we stock Yorkie in several formats including the original bar and the Raisin & Biscuit version, and Cadbury Boost as single bars and multipacks.