On a recent trip to Wine Country, I was convinced to go not only to sip on the best cabs and pinots Napa Valley had to offer, but to get down and dirty with a mud bath spa treatment from MoonAcre Spa and Baths at the Calistoga Motor Lodge.

Framed by vineyards and bike trails, with underground, geothermal hot springs of mineral water, Calistoga has a renowned history as a place of healing. Over half a century ago, members of the Wappo tribe were the first to discover a natural volcanic hot spring near the foot of Mount St. Helena. The rest, as they say, is spa-history, with patrons coming from far and wide to partake in the curative powers of Calistoga, by relaxing in a mineral hot spring or a volcanic mud bath.

The latter was what I had signed up for, though upon arrival, I was informed that enjoying MoonAcre’s ‘mudocracy’ was less a mud bath than it was a playful, mix-your-own mud bar. The new take on an age-old health ritual fit right in with MoonAcre’s updated and unbuttoned aesthetic and vibe. Still, it relinquishes none of the luxe factors you’d want in a spa, such as a selection of massages, facials, luxurious products, as well as specialty treatments starring Calistoga’s famed mineral water.

Modeled after a classic bathhouse, MoonAcre Spa and Baths puts a quirky spin on mineral springs and therapies from around the world. The spa features seven treatment rooms, and several, such as the changing room and the steam room, are covered in a soothing palette of soft mint and deep blue pool tiles, encouraging a deep-seated relaxation no matter your chosen experience.

Just outside the changing rooms, I sip a cold glass of lemon-cucumber water and admire the wall of words that advises snake oil and other restorative libations. The tongue-in-cheek signage tickles my writerly fancy (elsewhere, in a similarly tiled soak room with four standalone clawfoot tubs, a sign labeled ‘Pool Rules’ advises patrons ‘do not attempt duet event without partner’), though it is perhaps not for anyone who can’t laugh a little at life.

The MoonAcre spa itself is set serenely away from the bustle of the lodge, in a secluded area of the property. The spa is larger than it looks from the outside, with a large enclosed garden and patio area, with plenty of lounge furniture for quiet sunning. I catch a glimpse of the egg-shaped Acapulco and imagine myself lounging on it in the sun with one of MoonAcre’s mimosas or glasses of mulled wine, before reminding myself that I’m here to draw the toxins out, not imbibe them in.

A spa attendant arrives to escort me and my spa-mate to the outdoor sink, where she has set out two pails of dirt. What I learn, however, is that this isn’t just any garden variety dirt — this stuff is from France, and when mixed properly, becomes Green French Clay and White Caroline Clay.

She reiterates that this won’t be a traditional mud bath. I don’t particularly mind, since those require me to be neck deep in a tub full of ash, peat, and mineral water, waiting for the heat — generated by my own body and insulated by the mud — to draw out the toxins in my skin. To be absolutely transparent, I’ve never done a traditional mud bath, but I vastly prefer this DIY mud bar experience, since the mud is created in small, fresh batches, and I can still enjoy a full range of motion while waiting for my skin to purify.

Patiently, the spa attendant instructs us on how to properly cover ourselves with the clay. The White Caroline is for the face and neck and other sensitive areas, such as under our arms or behind our knees, an area of skin that, up until this very moment, I had given zero consideration. The green clay is for everywhere else, and we’re encouraged to really coat it on.

She shows us to the steam room, since the winds outside make it too cold to lay out in the darling patio garden. Inside, the air is a visible, white mist, and we giggle as we start smearing white clay on our faces, unsure if we are doing it right. We realize that we have been given permission to cover ourselves with mud and commit with enthusiasm. The white clay is fine and goes on smoothly, like an expensive night cream. The green clay is chunky and cool and gloriously gloopy, and we slather it onto ourselves before laying down, mud-side up, basking in the eucalyptus scented steam. My spa-mate immediate zones out with a cool towel over his eyes, so I am left to amuse myself. I check to see how the clay is doing, and in lifting my legs, discover that the color of the clay on my skin matches the beautiful green pool tile. I say as much to my spa-mate, and get nothing in response. My fingers slip and slide, redistributing the mud and coloring my legs, an experience remarkably like the fingerpainting sessions of my childhood.

After ten or so minutes, we go outside to rinse off the mud in the outdoor showers, where the spa attendant has also set fresh bowls of clay for us to paint our front sides. By now, the wind has died down considerably, so we opt to paint ourselves out in the enclosed patio. We take turns, each one laying face-down on the teal pool chairs as the other literally paints on the clay. It’s fun and whimsical in a way I hadn’t expected, taking a clean paint brush and using long brush strokes to color my spa-mate’s back, wrist up, wrist down, coloring inside the lines of my fellow mud-adventurer’s silhouette.

When both of our backs are coated with clay, we lay on our towels, ready to bake. It takes surprisingly little time for the mud to harden, and soon the back of my arm looks like it has developed an advanced state of Greyscale. Back into the eucalyptus mist we go, laying on our stomachs, and I watch as the baked clay on my arm slowly rehydrates over the course of our second steam session. Feeling utterly relaxed, I look out at the garden through the glass doors, and note dreamily the quality of the world through the condensation-heavy panels. The steam room meditation ends all too soon, as there is another pair that has booked the mud bar experience after us, but I can hardly complain because I am zen.

After a luxurious wash in the rainfall shower (make sure it’s a good one — the clay ends up in rather unexpected places), in which I use all the in-house, grapefruit-scented products, it’s time to head home, driving through Napa Valley but already dreaming about my next Calistoga spa trip.

1880 Lincoln Ave, Calistoga, 94515, (707) 942-0991