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Stones In Coffee: An Ill-Advised Investigation

2025-11-13 Entertainment
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James Hoffmann
James Hoffmann
2.5m subscribers

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Description

Note: All stones used in the testing came from the destoning of raw coffee - so are good indicators of the kinds of stones you might find in a bag of roasted coffee. What happens if a small stone makes its way into your bag of coffee and your grinder? An irreversible calamity or an imperceptible event? My 1 Cup V60 technique: https://youtu.be/1oB1oDrDkHM Our new pour over setup still life print from TensHundredsThousands: https://geni.us/THT-Still-Life 0:00 Intro 1:38 How do roasters filter stones out? 3:52 Our test parameters 4:46 Testing pt. 1 10:39 Burr inspection (with a microscope!) part 1 11:12 Testing pt. 2 12:02 Burr inspection (with a microscope!) part 2 12:31 Testing pt. 3 13:09 Particle size analyser results 16:41 What to consider if it happens to you 18:30 Testing pt. 4 21:49 Taste test Other Links: Patreon: https://www.patreon.com/jameshoffmann Limited Edition Merch: https://geni.us/TensHundredsThousands Instagram: https://www.instagram.com/jimseven Twitter: https://www.twitter.com/jimseven My Books: How to Make The Best Coffee At Home*: https://geni.us/howtomakethebestcoffee The World Atlas of Coffee*: https://geni.us/worldatlasofcoffee The World Atlas of Coffee Audiobook*: https://bit.ly/worldatlasofcoffeeaudio The Best of Jimseven*: https://geni.us/bestofjimseven Things I use and like: My old glasses: http://bit.ly/boldlondon My new glasses (Sept 2024 onwards): https://bit.ly/thenewglasses My hair product of choice*: https://geni.us/forthehair (*Affiliate links which may earn us a commission)

Top Comments (10)

@xavierinthetube 2025-11-13

James Hoffmann - Will It Blend Edition

3.6k 26 replies
@aokaze-minotaur 2025-11-13

Okay, hear me out: a video sequel exploring how much coffee you can replace with stones and not notice the difference. I'm serious.

2.8k 60 replies
@Sally4th_ 2025-11-13

7:05 Geologist in the comments! Hard to tell just from that pic but that looks like a worn basalt chip. Same for the larger piece. Basalt has a hardness of 5-6 on the Mohs scale which is less than those burrs are likely to be. It's also fine crystalline in structure so as soon as it's stressed it tends to shatter into sand.

2.1k 54 replies
@GHomes5 2025-11-13

21:54 “I must taste the stone.” Glad to see James is keeping Hames Joffman alive in spirit.

2.0k 13 replies
@snow-1904 2025-11-14

Future coffee myth: Adding stones into your beans increases the mineral content, increases the pH level, and enhances the coffee flavours.

1.2k 17 replies
@edskodevries 2025-11-13

"What are you watching hon?" "It's.. complicated."

741 4 replies
@djsnowman06 2025-11-14

I am an assayer, we grind stones for a living. In the first lab i worked at we had a Bico Pulverizer. It is just a large flat burr coffee grinder. I fed that thing 18-20mm stones by the scoop, 6-8hrs a day, 7 days a week. It is not surprising in the slightest, that those high power grinders can eat rocks. Cheers!

591 9 replies
@ryanstuart4054 2025-11-14

Never in my 20+ years of making and drinking coffee multiple times a day have I ever found a stone in the beans… until this morning. Even more strange, looking at this video’s published time, is the coincidence that it went live at roughly the same time as I found this morning’s delicious stone 😮

278 8 replies
@petercort3566 2025-11-14

23:25 "This is getting weird". Started a lot sooner than that 😂

89 1 replies
@GuysAndGals 2025-11-25

5:00 "We don't want static" - in a Stones in Coffee video, is just gold

20

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