Watching the squirrels start to bury choice acorns, I wonder whether the desire to hoard summer's precious edible loot isn't hard-wired.

In my experience, fermentation -- or letting salt-brined vegetables sit at cool room temperature until they turn pleasantly tart -- is the safest and easiest of all preserving methods. It lends the vegetables a thrilling acidic kick and fine, lacy carbonation bubbles -- so much verve, in fact, that fermented foods often seem more alive after being preserved than they were before.

Sauerkraut is probably the most infamous of the ferments, but the buried acorns got me thinking about kimchi -- the spicy, garlicky, tingly tart-fermented pickle that accompanies nearly every Korean meal -- because during the heat of summer, it was traditionally fermented in buried pots underground.

Because kimchi is so essential to the Korean table, its variations are vast. Traditional kimchis, usually made from napa cabbage and/or daikon radish, last a long time. There also are stuffed or fancy kimchis, which can be eaten fresh or kept for a few weeks. Water kimchis are light, less spicy ferments, intended to be eaten within a week or two.

In order to dig deeper into the traditional art of kimchi, I knew I needed to watch an expert's hand at work.

A surprisingly large number of rural northern Minnesotans are aware of the Korean food outpost in the small town of Solway, just west of Bemidji, not far from my home.

The S & S Outlet and Asian Market is difficult to describe: You could call it a thrift store hijacked by an Asian grocery, or an old-time trading post, or just the place that smells of sesame oil and rice, where working guys in Carhartt overalls can sit at the oil-clothed front table spearing big triangles of Korean kimchi pancake.

Here you can buy everything from frozen tteok (pronounced "duck" -- a chipped rice cake that can be hard to find even in the Twin Cities) and sweet potato noodles to used snowmobile helmets and old coffee percolators. But really, most people walk through the front door for the kimchi.

Last week in the back commercial kitchen, the obvious heart of the place, Minam Morris, cook and proprietor, had everything laid out to make traditional napa cabbage kimchi.

She didn't chop it, but instead quartered the cabbage, washed it, and rubbed salt into every leaf. After about an hour, she rinsed it well and wrung it out hard, as if it were a hank of linen. She stirred together a devilish slurry of Korean red pepper powder (more coarsely ground than cayenne, and a bit less spicy), finely chopped garlic and ginger, and julienned vegetables: carrots, daikon, and sour apples. She would have liked to use a crisp Asian pear, but thought that the tart local apples would impart a similar fruitiness. For the essential something-fishy, she added a spoonful of salted shrimp, although fish sauce would work, too. "And kimchi with fresh oysters is my favorite," says Morris.

Bundling up the stuffed kimchi quarters carefully, she tucked them snugly into a plastic container and pressed down until the liquid, rusty colored from the chile flake, rose to the top. "This will be really good made into a stew with pork ribs, especially when it starts to get cold outside," she said with a smile. "The mechanics across the street really like that for lunch."

Another expert weighs in

But how would the kimchi treatment work for other fall vegetables? I queried my former colleague Jason Lee, now the sous chef at Murano in London, because I remember eating his Korea-born mother's perfect kimchi when he brought it to work -- by the bowlful, as if it were cereal -- and marveling at the way the notes of pear and ginger survived the magnificent chili heat. He came through with some of her more unusual recipes: eggplant kimchi, a traditional bundled napa kimchi similar to Minam's, and best of all, a stuffed cucumber kimchi.

According to Morris, such bundled and stuffed kimchis are considered fancy or for special occasions, so instead of being mixed into a stew or a stir-fry, they're usually given center stage and eaten as part of a proper Korean meal -- with rice, maybe some grilled meat, and a soup or vegetable. After curing at room temperature for three days, the stuffed cucumber kimchi accrued the perfect balance of tartness to weigh against the gentle heat. The bundles sat on the plate in a shiny pool of red liquid, the fanned-out cucumbers clinging to their center tumble of shredded vegetables, keeping them close.

Beyond traditional

The foray into more unusual kimchis stirred up some wild ideas. What about rutabaga kimchi? (Even worse than you can imagine.) Or zucchini? (That works, and it kills on a pork burger.)

Both western cabbage and zucchini make good kimchi, as long as you follow the basic principles: salt, rinse, mix with the chile slurry, let sit at cool room temperature to ferment (three to seven days) and then refrigerate to slow the souring action. Generally, the garlic element should be heavier than the ginger, some people add sugar, and usually there's some sort of fishiness. For vegetables that don't exude enough liquid to cover themselves as they ferment, you can add water to cover.

In fact, water kimchi is a genre all its own.

Rachel Yang, chef at both Joule and Revel in Seattle, makes a few different water kimchis to complement her menu, a skillful cross-pollination of French and Korean flavors and techniques. She places a small stack of fennel bulb kimchi alongside a seared cube of tuna, for instance.

But, this time of year, she likes to make a subtle kimchi of thinly sliced rounds of candy-stripe beets along with their chopped greens, and plenty of garlic.

"Kimchis like the water beet are delicate and really meant for summer," said Yang, who noted that they are more perishable, and won't last over two weeks.

A tangle of gently garlicky, woozy pink rings? I doubt the beet kimchi would be around that long.