A refrigerated case displays kombucha at the Giant in Silver Spring, Md. Why is it always surrounded by caution signs and absorbent booms? (John Kelly/The Washington Post)

Caution. Attention. Cuidado.

That’s what it says on the yellow pylon planted next to the refrigerated kombucha case at my local Giant grocery store.

As well it should. Who knows what that stuff is capable of?

My Giant installed the kombuchateria about six months ago. I’m guessing some grizzled grocery executive made the decision grudgingly. “Milk and bread I get,” I imagine him saying. “Ranch dressing, ice cream sandwiches, Saran Wrap, Spam — but kombucha?”

“It’s big with millennials,” said the whippersnapper with the iPad and the nose ring. “Kombucha screams ‘wellness.’ ”

Of course, it screams. It’s alive.

They put it between the produce section and the deli department, in an end cap on an aisle that has organic breakfast cereals on one side and potato chips on the other. I can’t remember what used to be there, such does the future overwrite the past.

I first saw kombucha a few years ago on a trip to Portland, Ore. A big jar full of a brackish liquid sat near the cash register in a craft store and gave off a vinegary tang. It did not seem like something I would enjoy putting in my mouth. But then again, Stilton, oysters and grappa all took some getting used to.

Kombucha is sugary black or green tea, dosed with a yeasty puck called a “scoby”and left to ferment. It’s getting its moment in the sun because of something that’s usually kept in the dark: the bacteria in our guts. Komboosters say the drink encourages these valuable flora to bloom.

Gut bugs are the latest craze in the world of health. Each of us has trillions of them inside. Together, they weigh more than our brains. It makes you wonder who’s in charge: us or them?

Anyhoo, back to the Giant and that sign: Caution. The sign is always there. And often while I’m shopping, I hear an announcement over the store’s speakers: “We need a mop in front of the kombucha case.” “Cleanup in front of the kombucha case.”

What is it with that stuff? Is the kombucha trying to escape? All those little corked-up beasties eager to make a run for it, recruit the microbes in your gut and launch an uprising: Mad Max Beyond Thunder Microbiome?

Or is the pent-up effervescence too much for the caps, causing the screw tops to pop off and geysers of kombucha to spew out?

Maybe the bottles slip out of customers’ hands and crash to the floor when shoppers have second thoughts about sipping something called a Gut Shot.

Determined to find the answer, I confronted a Giant employee: What’s up with the kombucha?

He said the refrigerated case leaks. You know how refrigerators and AC units can be: pesky water droplets forming around the chiller, condensate lines getting clogged.

A believable explanation, but was it him talking or the gut bugs?

The iron age

People are sometimes surprised to hear that I iron my own shirts, not because they think I’d employ someone for that, but because they can’t believe anyone wears shirts that need ironing these days. Well, I find that even those no-iron shirts look wrinkly in their natural state. I want to look sharply dressed, not Shar-Pei-ly dressed.

Those of us who iron — iron workers, I guess you’d call us — revel in the hiss of the steam and the smooth glide of the triangular base plate across the Oxford cloth. It’s a mindless task, but a satisfying one.

But we know that an iron can be a harsh mistress. You only have to push the cleaning button with the iron resting atop your garment once to learn never to do that again: It can leave the shirt with little brown dots, like a spray of buckshot.

But the worst happened to me the other day. It’s an experience akin to getting a corked bottle of wine: I pulled my shirt from the clean basket and tossed it atop the ironing board. I started as I always do, with the button side of the shirt front. I moved slowly from the shirt tail to the shoulder, letting the iron do the work.

I pulled the shirt over the edge of the board and started on the right half of the back. Then the left. Then the placket side of the front.

Next were the sleeves and the cuffs. Finally, it was time for the collar, which I always iron through the back side. (I read that in a magazine.)

The shirt was as crisp and white as a new piece of chalk. Or seemed to be, for when I went to lift it from the board, I saw — horror! — a tiny spot on the front of the collar that the washing machine had failed to remove.

All my work for naught! But at least I got to iron another shirt.

Twitter: @johnkelly

For previous columns, visit washingtonpost.com/john-kelly.