(Photo: Summer Cartwright)

In a city that dyes bagels rainbow and makes spaghetti into donuts, it only makes sense that milk can be trendy. On trend now: oat milk. But, like all things in fashion, trends change. Which means it’s not too early to wonder: What’s the next oat milk?

Oat milk (a pulverized liquid made from water, oil and oats) grew in popularity at coffee shops earlier this year, meaning its figurative shelf life is coming to an end. (Its literal shelf life is 5 days, with the option to refrigerate or keep at room temp.)

Just as high-to-low skirts were kicked to the curb by denim button-ups, almond milk was replaced by oat milk as the lait du jour. Before that, soy was No. 1. But there are contenders  lurking in the corner. No, we’re not talking about smoked raisin milk. It’s hemp and macadamia nut milk that are out to out-hip the hipsters’ current fave.

According to baristas throughout the city, these milks are being asked for more and more, a sign that the ascent of hemp and macadamia is nigh. “We had people asking if we had oat milk for months before we got it,” said Emma Stratigos, the general manager at Gregory’s Coffee in Lower Manhattan.

Baristas like Stratigos are the first to sniff out the milk that’s soon to be filling their shelves because, obviously, they take the orders and make the drinks. They know what people want and what they’re intrigued by, and sometimes are the ones to make the change happen.

Jesse Gan, a barista at Kona Coffee in East Village, wrote a letter to upper management at his previous gig alerting them to the demand for oats, which he said led Toby’s Coffee Estate to hop on board the trend train. “Oat milk is thicker than some of the other milk alternatives, which makes it feel like you’re drinking a milk latte,” said Bianca Linz, a Kona regular.

Nut milks are sweeter and more watery than oat milk, said Linz, who got macadamia milk today because the oat substitute was out of stock.

Gan said macadamia milk is popular for other customers at Kona because of the Hawaiian-inspired menu, and because of its taste. He thinks the oil in oat milk will soon turn people away as they learn it’s in the drink. Additionally, he said almond milk is less likely to experience shortages, something that happens frequently with oat milk.

Gan and Caleb Church, a barista at Bluestone Lane in Soho each said the upside to the trend is that oat milk produces frothier, thicker lattes than nut milks. “I don’t think there’s any [dairy alternative] better,” Church said, noting that macadamia nut milk could be the one soon on top.

As for hemp milk, Cynthia Sitarz, at Gasoline Alley Coffee in Soho, says its neutral flavor beats that of oats.

At NYC coffee shops, oat milk usually costs around $1 extra, or as much as other dairy alternatives. Baristas predict hemp and macadamia milks – if they grow in popularity —would cost the same.

The uncertainty over what will top the milk-but-not-milk kingdom remains, but there’s one alternative likely to never quite reach peak fame.

“Pea milk,” said Gan. “What an unfortunate name.”