Quantum Coffee Roasters

Opening Times
Mon - Fri8am - 6pm
Sat9am - 6pm
Sun10am - 6pm

58 Bute St, Cardiff CF105BN
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Why we love it

Run by Katia and Dimitri, two of the bay's most welcoming coffee aficionados, Quantum Coffee Roasters really do go beyond the bean. Combining Heisenberg-esque scientific precision with craft, love and a purposeful embracing of coffee's creative possibilities, every Crisp Chemex, Filtered V60, Bracing Cold-Brew Tonic and Rich Espresso created here is a veritable work of art - and well worth taking more time than usual to fully enjoy.

Snugly situated on the corner of Bute Street, you'll notice Quantum by its modernista glass frontage, chilled-vibe (professional-friendly, loved by creatives and open to all) and the unmistakable aroma of coffee beans. Freshly roasted in-house, these small batches are hand-selected from locations as far reaching as Papua New Guinea, Thailand, Burundi, Ethiopia and Guatemala - and the resultant cups (from Katia's Quantum-blend to Dimitri's speciality single-origin beans) live long in the memory.

Squidgy sofas, upside-down plant pots and hanging cameras from a bygone era adorn the interior, with weathered signage, exposed brickwork and factory lighting giving a utilitarian touch or two (reminiscent of the Bay's industrial past). Quantum's aesthetic is as individual as its coffee - balancing a well-engineered scientific process with a good dose of heart and soul.


Try the Gravity Coffee Ale - a unique colab between Quantum and Mad Dog Brewery
The Chemex and V60 pour-over coffees aren't to be missed
Check out the coffee roaster in the corner of the café

Top Wriggler reviews

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I like this coffee shop. Good place to get on with work, excellent level of service with simple food and tasty coffee delivered fast and friendly.


Nice coffee house and good coffee. Nice staff too.


Quantum is my go-to out of all the coffee shops in Cardiff. The staff are warm, friendly, and knowledgable, and you never feel like you’re intruding if you stay there for a while! The coffee is the best in the capital, and the cakes and warm food is just lush. Lovely atmosphere, and I love the decor - including the information about the old docks. Would highly recommend!


Good food, great location


Great, friendly staff and great selection of specialty coffees.


Cool quirky coffee beer