His tail twitches as he catches the scent.
Looking first to his owner, he jabs with his paws, earth shooting into the air as he gets closer to the prize.
I'm in the Tuscan town of San Miniato for the November "gold rush," when the Italian white truffle comes into season.
This rare white fungus is as fabled as Moby Dick, and just as elusive.
That truffle emotion
"The truffle is an emotion. It's not a product, it's not a taste," explains my guide Massimo Cucchiara, who's from a family of truffle hunters that reaches back three generations.
"It's an emotion when you find it. It's an emotion when you eat it. I still remember my first truffle like I remember my first kiss."
Massimo's garlicky scented mistress grows underground, close to the roots of oak, hazel, poplar and beech trees, and is only found in a handful of places around the world.
It's this rarity that makes it so prized.
Truffles are one of the world's most expensive foods and the Italian white is the most valuable of all, with a market price of up to €4,000 ($4,400) per kilo.
Like that heady first embrace, it's impossible to reproduce.
"It's nature that decides it," he explains. "We can't cultivate the truffle."
The San Miniato Hills, with their mild Tuscan climate and soil rich in mineral salts, are the perfect breeding ground for top-quality truffles -- as well as the wine and olive oil for which the region is famous.
Beware of imposters
The rarity and expense of the true white truffle means imposters are rife.
Chances are, if you've tasted white truffle you've been eating chemically enhanced tuber borchii -- an inferior Italian truffle similar in appearance but incomparable in taste.
The second-rate truffle is sprayed with a harsh artificial aroma that mimics the smell and taste.
"When I go into the restaurant and I get that smell I don't eat the truffle dish," says Massimo.
As for truffle oil -- most commercial oils are synthetic gloop unworthy of washing Pepe's paws.
"When you eat the pasta with the truffle oil you don't taste it with your mouth, you taste it with your nose."
The gentle, earthy taste of Italian white truffle is too subtle to be preserved in oil or cheese or meat.
Massimo's father, Salvatore, kneels down to unearth our first find of the day, brushing at the soil with his fingers with all the care of an archeologist on a dig.
It's a 25-gram golden-brown beauty, worth up to $100.
Its firm texture, umber hue and marbled white-brown interior revealed along a nibbled edge all point to its freshness and ripeness.
Then there's the gentle, earthy musk, which builds as it warms in the hand.
When eaten, "the taste is delicate in your mouth," says Massimo. "The smell though, you could smell for days."
Dogs, not pigs
Hunters guess at where the year's harvest might be found by judging the weather, the earth and the plants.
But most of all, they rely on their dogs -- rather than the pigs of legend.
"It's the dog that teaches you," says Massimo. "Every day you have a new lesson."
Pigs might have the sensitive snouts required for the job, but their use is banned in Italy because their overeager rooting damages the truffles' delicate mycelia, the spore-holding web necessary for the fungi's reproduction.
Also, it's pretty dangerous to get between a 300-kilogram pig and a truffle it's determined to eat.
A particular set of skills
Pepe, our dog for today, is a mix of springer spaniel, Segugio Italiano and setter.
Like his owners, Pepe is from a long line of hunters.
His is a hardy mongrel combination that ensures energy, stamina and a keen sense of smell.
While Massimo and I talk, Salvatore and Pepe walk ahead, communicating in a private language built up over nine years of working together.
"It's important to know your dog, have empathy," explains Massimo. "You can speak about everything. After a while you speak about your problems!"
Ancient pilgrim route
San Miniato is a quietly beautiful medieval hill town, centered around a tower fortress that commands views over the Arno Valley, with its cypress and olive trees.
The forest, wineries, and tiny villages of the San Miniato hills lie to the south, while to the north is busy industry.
Santa Croce sull'Arno is the heartland of Italian leather manufacturing.
An ideally positioned base for exploring the cities of Florence, Pisa, Siena and Lucca, San Miniato is on the ancient Via Francigena pilgrim route that stretches from Canterbury, England, down to Rome.
Today's pilgrims come for the annual truffle festival held here during the last three weekends in November, when the normally sleepy town fills with life.
Honored with statues, lamented with funerals
Here, truffles are honored with statues.
There's a bronze tribute in the town center to the world's largest truffle, a two-kilogram beast found in San Miniato in 1954.
Funeral processions are held for them.
In 2004, a $52,000 truffle was at the center of a media storm after being bought by a London restaurant.
When the truffle spoiled after being incorrectly stored, its remains were brought back to San Miniato for a lavish homecoming lament
A lesson, then, in the importance of knowing how to care for and prepare the truffle.
Continuing our journey from earth to plate, we visit Italian TV chef Gilberto Rossi at his restaurant Pepenero
, for a masterclass.
How to prepare the white truffle
"We never cook the white truffle," explains Gilberto, as he takes white truffle butter out of the fridge, ready to make tagliolini al tartufo.
The butter is made by mixing it with leftover truffle shavings and leaving it for a week for the flavor to take hold.
Brash oils have no place here.
Butter, egg or mascarpone are the only suitors gentle enough to marry with the white truffle.
"If you don't know how to use the truffle, you kill the taste in a few minutes," adds Massimo.
Simplicity is key.
While the fresh tagliolini is dropped in boiling water, the eggs and butter are mixed to create a creamy base for the pasta.
Gilberto serves the pasta, swirling the strands around the spoon, then shaves about eight grams of San Miniato white truffle on top.
We eat it with L'Erede
white sparkling wine from local winery Ivana Cupelli.
A typical Tuscan Chianti would risk overwhelming the dish.
"Sometimes it doesn't work when you mix two diamonds," says Massimo.
And the taste?
Hail to Gilberto, Massimo and all followers of the one true truffle.
As someone only previously acquainted with mid-range truffle oils, it's an awakening.
The next day at the San Miniato Truffle Festival, I eat two dishes prepared by volunteers from the local Truffle Association, served on plastic tableware inside a marquee.
They couldn't have tasted better if they'd been served on gold platters by diamante unicorns.
First, carpaccio of Tuscan Chianina beef, seasoned with lemon juice, salt and pepper, and served with valeriana salad, pine nuts and shavings of white truffle and Parmesan.
On the side, white bread spread with soft mascarpone cheese and topped with a sliver of truffle.
And then for seconds -- because there always should be seconds -- there's silky, creamy risotto, flavored with broth and seasoned with salt and pepper, and crowned with generous flakes of Tuscan gold.
White truffle season lasts from October to late December or early January.
A truffle can be stored, wrapped in paper in the fridge, but only for up to 10 days.
So when they're gone, they're gone.
In the meantime, there's the Italian black winter truffle, in season from December to March, and the black summer truffle, found from May to September.
"We go hunting all year," says Massimo.
The truffles change, and the dogs change -- Pepe turns his nose up at black truffles, so one of his siblings will step in.
But the hunt goes on.
Truffle in Tuscany tailor make truffle hunting and tasting experiences led by Massimo Cucchiara, from €65 per person ($71) for two to four people; truffleintuscany.it
; +39 347 903 0371
Chef Gilberto Rossi offers cook-and-eat sessions in his San Miniato restaurant followed by a truffle hunt, from €180 per person ($198) for groups of eight to 20; Pepenero
; Via IV Novembre, 13 56028, San Miniato; +39 0571 419523
Serenella Barbieri offers private, three-hour guided tours of the San Miniato Truffle Festival from €130 per group of up to 30 people ($143); firstname.lastname@example.org; +39 347 0740223
To Tuscany offers villa rentals across the region; Gallo 1, near Montopoli in Val d'Arno, starts at $537 per week; to-tuscany.com; 0121 286 7782