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Coffee rings and Google

I have forgotten, if I ever knew, about how coffee rings form. And Google sucks.

Nearly every morning I pour myself a cup of coffee. Hot, iced, whatever — into a clean vessel, a mug or glass, often straight from the dishwasher having been run the night before. Every time (or every time I think to look) there is instantly a small ring puddle, a footprint of the vessel, on the counter.

I did not spill.

I am not including times when I spill, those times when there’s a splash that hits the counter or when I miss more closely and some hits the rim and flows down the side. You can see it when it happens, and there’s other trace evidence — spatter, traces of rivulet. You might even hear unexpected sounds of unexpected impacts if you’re otherwise attentive in a quiet setting.

I’m supposing some minor mystery of science on which much has been said. One that I am sure I was taught about by Mr. Hall in my 8th Grade Science class (mostly a physics class, where, if nothing else it seemed everything was fair game for a Newtonian force vector diagram).

Off to Google.

The Google results are shit.

The only thing close to an appropriate result is a Quora thread, where someone asks the same thing I am asking and everyone seems to suggest he actually spilled and didn’t know it. Or there was a hairline fracture in his mug. I know I didn’t spill. And I use a wide variety of vessels, none (let alone all) have a hairline fracture. Pigfucker Quora trolls are gaslighting this poor man and me.

There’s some seemingly bullshit answer about condensation, but water from the air would condense on the outside when I have a cold drink. Not coffee. And not with a hot drink in a cold room.

There are a lot of other interesting articles, adjacent but still seemingly irrelevant, about the actual nature of the coffee ring itself: how it’s thicker at the edges and capillary flow and evaporation being the cause. Fine. Many of them specifically suppose one spilled their coffee or describe the effect on the inside of a coffee mug. (Some allege an impact on flavor and enjoyment? I did not check to see if these web sites also had guidance on which crystal to deploy next to my coffee maker or to pair with my eggs.)

Many of these articles seem to appear around the same time as each other because some scientific paper on capillary flow came out or something (I don’t know, I didn’t go that far down the rabbit hole). They have headlines like, “Ever wonder why spilled coffee dries to leave a ring?”

NO! I don’t spill my goddam coffee. I’m wondering how the coffee got there in the first fucking place and I don’t wonder about the actual nature of the ring left behind I always intuited it was something like a capillary effect without so many words Jesus fucking Christ.


I don’t know, maybe I spilled my coffee.