Carlos Arnaiz doesn’t usually carry cash. But to fund his delicious habit, he sure needs it.

Every Saturday morning, the 41-year-old architect ventures to She Wolf Bakery stand at the Fort Greene Park Greenmarket for a weekly fix of artisanal bread. After making his selections, he counts out a fat stack of singles pilfered from his wife’s wallet (and sometimes his kid’s allowance, he admits). Last Saturday, he chose three small half loaves — and parted with a whopping $17.

“In my estimation, it’s a good investment,” the Fort Greene resident says of the bread, which he and his family enjoy slathering with butter and honey. “It has an incredible, layered flavor — there’s this tanginess. It’s stupendous.”

In NYC, luxe loaves are becoming as ubiquitous as $6 pour-over coffee and $15 chocolate bars. Each week, She Wolf bakers arrive at the Fort Greene farmers market with 17 large bins of bread — including their most expensive, a $20 miche made with Farmer Ground organic flour. And each week, the stand attracts a long, hungry line that quickly buys out the supply.

They’re not the only the game in town, either. “There are more artisan bakeries than there were 10 years ago,” says Francisco Migoya, a baking instructor and co-author of “Modernist Bread” (out Nov. 7, the Cooking Lab).

A dip in carbphobic diet fads may be stoking demand. “People are starting to be less afraid of bread and gluten,” Migoya says, noting that Google searches for terms such as “gluten intolerance” have declined since peaking in 2013. “People are starting to change their minds about bread.”

But why blow 20 bucks on a loaf when, for the same price, you could buy eight loaves of perfectly sliced whole-wheat sandwich bread at the Mr. Mango market a couple blocks away?

Many customers, such as Angelina Drake, a 29-year-old nonprofit executive from Fort Greene, view their tony bread habit as part of an overall commitment to living their best lives.

“If you’re going to eat bread, you might as well eat good bread,” she says of her $11 purchase. “It challenges me to bring the rest of my meal up to par. I’ll get good olive oil from Eataly — maybe some Sicilian spicy oil — to dip it in.”

‘It’s a treat that we have on the weekends — a nice, bourgeois treat.’

Eric Vazquez, a professor from Clinton Hill, says he and his partner eat mostly vegetables and protein but occasionally allow themselves a quarter loaf of She Wolf miche — a precious morsel of carbs that costs $5.

“It’s a treat that we have on the weekends — a nice, bourgeois treat,” says the muscular 37-year-old.

Splurging on a full loaf wouldn’t be out of the question. “Twenty dollars is like the cost of a cocktail now, so I guess we could just have one less cocktail,” he says. “And the bread keeps us fed longer.”

Not everyone is sold. Clinton Hill resident Kaylah Majeed, 25, strolled past the She Wolf line last Saturday to peek at the price tags — and promptly turned the other way.

“Bread doesn’t usually last that long, so it’s just kind of a lot to spend,” says the advertising agency producer, adding that a lot of people — herself included — can become so entranced by the farmers-market atmosphere that they end up overspending on fancy food.

“I think it’s aspirational,” she says.

Bakers say the cost reflects their better-quality ingredients and the long process of making and fermenting artisan dough, which often takes 12 to 48 hours.

“Time is the most expensive ingredient that goes into a bread that ferments really slowly,” says Uliks Fehmiu, co-founder of Pain D’Avignon breads, which has a storefront at Essex Street Market and sells loaves for up to $13.50.

Boerum Hill bakery Bien Cuit makes a $10 miche that ferments for 68 hours, its bakers say. The bakery’s most expensive loaf, a raisin-walnut sourdough, is $13.

Making good sourdough is particularly time-intensive. The process begins with a live starter, a pungent glob of flour, water, wild yeast and bacteria that requires special nurturing. In addition to making bread rise, it imparts a complex, mildly tart taste that’s lacking in many breads made with standard yeast and sugar.

For small-scale bakers, keeping that precious starter alive is an all-hands-on deck situation, says Keith Cohen, owner of Orwasher’s artisan bakery on Amsterdam Avenue, whose crew works every day to maintain operations.

“Even in [superstorm] Sandy we got people in to look after our starter,” he says.

His loaves are priced at up to $12, owing in part to locally farmed flour that’s roughly five times the cost of standard commercial flour, he says. He’s willing to shell out for well-sourced ingredients — and so are his customers, he says. Before feast-centered holidays such as Rosh Hashanah and Thanksgiving, lines form out the door, and customers on average spend about $30 on their bread buys.

“It’s controlled chaos,” Cohen says. “We’re there at 4:30 a.m. and have to open early, at 7 a.m., to keep the line moving.”

Zachary Golper, co-founder of Boerum Hill Bakery Bien Cuit, says that operating in the five boroughs — complete with kitchen space, a brick-and-mortar cafe and a full staff — means that local breadmakers have to be breadwinners.

“The reality is, I’ve got a business to run in New York City,” he says.

Nevertheless, Alex Bryan, 22, finds the rise in bread prices excessive. The Williamsburg-based stock trader scoffed at the high-cost loaves being sold at the Union Square Greenmarket as he commuted to work.

“I’m sure if you toasted it, it would taste the same as the sandwich bread from the grocery store,” he says. “I bet a lot of it is emotional — you feel good supporting the local farmers and all that. You might think the bread tastes better for that reason, but that might be a placebo.”

Don’t bother telling that to She Wolf customer Sue Peng.

“These are the closest thing I’ve had to the baguettes in Paris,” says the 41-year-old Fort Greene analyst, clutching a long, crusty $4 baguette in one hand and the handle of a stroller in the other. “If it’s good, it doesn’t matter how much it costs.”