Quantum Coffee Roasters

4.5 ( 424 reviews )
Checking... 8:00 AM - 5:00 PM See Hours
£1–10
58 Bute St, Cardiff CF10 5BN, United Kingdom
+44 7413 543335
Quantum Coffee Roasters is a hidden gem located at 58 Bute St, Cardiff, offering an inviting atmosphere and exceptional coffee. Each visit promises friendly service, as noted by patrons like Harry Steel, who praised the calm vibe and well-prepared drinks. The coffee here hits the mark, boasting a perfect balance of sweetness without bitterness, with steamed oat milk that is often just right—something many coffee lovers appreciate. The menu features enticing specials such as the Baileys Flatte and Nitro Cold Brew, all reasonably priced. Regulars like Zaka Khaliq compliment the skillful latte art and smooth blends, making it an ideal spot for relaxation or casual conversation. With offerings ranging from vibrant smoothies to unique hot chocolates, Quantum Coffee Roasters ensures there’s something for everyone. In addition to the delicious beverages, the clean and cozy decor enhances the experience, creating a perfect backdrop for enjoying quality coffee. While some customers have noted specific preferences, such as bean selection, the overall consensus points to a remarkable commitment to crafting specialty coffee. Whether you’re a local or just visiting Cardiff Bay, Quantum Coffee Roasters is a must-try destination for any coffee aficionado.

Amenities and More

  • Accessibility
    • Has wheelchair-accessible entrance
    • Has wheelchair-accessible seating
    • Has wheelchair-accessible toilet
    • No wheelchair-accessible car park
  • Service options
    • On-site services available
    • Offers takeaway
    • Serves dine-in
    • No delivery
  • Highlights
    • Serves great coffee
    • Serves great dessert
    • Has great tea selection
    • Has live music
  • Popular for
    • Good for solo dining
    • Good for working on laptop
  • Offerings
    • Serves coffee
    • Has free water refills
    • Quick bite
    • Serves vegan dishes
    • Serves vegetarian dishes
  • Dining options
    • Serves lunch
    • Serves dessert
    • Has seating
  • Amenities
    • Has gender-neutral toilets
    • Has toilet
    • Has Wi-Fi
    • Free Wi-Fi
  • Atmosphere
    • Casual
    • Cosy
    • Trendy
  • Crowd
    • Family friendly
    • Good for groups
    • LGBTQ+ friendly
    • Popular with tourists
    • Transgender safe space
  • Planning
    • Doesn't accept reservations
  • Payments
    • Accepts credit cards
    • Accepts debit cards
    • Accepts NFC mobile payments
    • Credit cards
  • Children
    • High chairs available
  • Pets
    • Dogs allowed outside

Reviews For Quantum Coffee Roasters

Harry Steel
Apr 23,2025
Had a trip down to Cardiff bay for a short break and was anxious I wouldn’t be able to get my usual morning coffee fix. After a quick google, we found Quantum Coffee Roasters and decided to give it a go. Service was excellent- friendly, helpful, didn’t feel rushed or pressured. Ordering was painless, easy, and enjoyable. The atmosphere was calm and cosy. I had second thoughts about getting a take out! And, mostly importantly, the coffee was great. Really excellent. Not bitter, not sour, bang in the sweet spot. The oat milk was also steamed to the right temperature. Which quite a few coffee shops seem to get wrong and burn the milk (and my tongue!). We managed to visit twice during our stay, and both times were exactly the same. Even with different baristas on both days. Always friendly and made perfect coffee. It’s a shame that Quantum Coffee Roasters isn’t near my home!! Will definitely be visiting again the next time I’m in Cardiff bay. Couldn’t recommend highly enough.
Zaka Khaliq
Apr 20,2025
Quantum Coffee Roasters in Cardiff is a great spot for coffee lovers. I had a latte, and it was smooth, creamy, and perfectly made, with some lovely latte art on top. The place has a cozy, laid-back vibe, making it ideal for a chill hangout or a quiet coffee break. The staff are super friendly and know their stuff. Definitely worth a visit if you’re in the area!
NGW
Mar 23,2025
Lovely coffee shop with friendly staff and really nice coffee, I was shocked that a flat white was 3, when Costa serve up an inferior one for 3.75! Very clean and nicely decorated.
Pan Yaso
Mar 15,2025
Really nice coffee , nice space for chatting with friends and working staffs are friendly they have specialty coffee retail shelf as well . Highly recommend but no my favourite ham cheese croissant
G C
Mar 14,2025
Nice cafe just round the corner from Cardiff Bay. Friendly staff and very relaxing atmosphere. They carry a variety of beans although they are for sale and you can’t choose what your coffee is made of. On my visit the only choice for a drip (filter) coffee is from Yunnan China. Coffee was nicely brewed but a little too weak for my taste. I still enjoyed it though. It’s always nice to have freshly ground and brewed coffee.
Jimin Choi
Feb 25,2025
First time in a while I ordered an espresso and actually enjoyed it. Most "cafes" have it on their menu but they haven't got a clue how to make it, so why sell it at all? It's infuriating because it's a minor fraud, promising something they can't deliver at all. Thankfully this place knows how to do it. The drink was sweet, smooth, thick and pleasant. Also there's no silly music blasting in the background so you can focus on your drink.
Riley Tang
Feb 21,2025
I had a pleasant time in the cafe. Wonderful Nitro Cold Brew with delectable blueberry muffin. The overall atmosphere felt cosy and the baristas were welcoming and helpful.
Meike
Feb 5,2025
I had a vegan Muffin with Pistachio and an Americano. I also tried an vegan Biscoff Latte. It was very delicious. The staff was very friendly. I recommend this coffee shop!

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