Slate Milk Raises $23 Million Series B Round To Bolster Protein Drink’s Rapid Growth

Slate Classic Chocolate milk shake

A new slate of functional beverages is about to dominate the ready-to-drink shelf, ushering in a more modern era of easily incorporating more protein in our diets.

Today, Slate Milk cofounders Manny Lubin and Josh Belinsky reveal the brand has raised a $23 million Series B funding round.

Led by Foundership Ventures, a new fund by Yasso frozen greek yogurt cofounders Drew Harrington and Amanda Klane, the money will allow Slate to continue its momentum towards ubiquity as it hits 100,000 points of distribution across 20,000 stores nationwide by the end of 2025.

Slate also reveals that it is rolling out several line extensions including a 20 gram protein Strawberry milk at Sprouts Farmers Market, a 30 gram protein Cookies & Cream milk at Target, and a 30 gram protein Salted Caramel flavor at Walmart and Albertsons banner stores.

New “Ultra” 42 gram protein options in Chocolate, Vanilla and Salted Caramel will also be available in retailers across the country.

“Stores where we may have just had our ready-to-drink lattes, now we’re adding our shakes, and vice versa. We’re adding new partners and executing deeper with our existing partners,” Lubin tells me.

The impressive growth is due to Slate’s early entry into the high-protein product space slightly before it caught mainstream attention–ready to execute immediately once consumers craved it most. Slate’s macronutrient ratios are practically unbeatable, largely due to the utilization of ultra-filtered milk. It’s a protein drink that writes a new script about who protein drinks are for.

“We’re not sons of dairy farmers. We had no milk history,” Lubin says “We’re just a couple of dudes from the burbs of Boston who like chocolate milk.”

Slate cofounder Manny Lubin

Slate’s brand has evolved significantly in just the past six years since it launched, creating several clean slates along the way. “When we started, protein shakes were thought of as supplements,” Lubin says. He simply wanted a chocolate milk, which he loved as a child, that matched his evolving lifestyle. “You have kids chocolate milks and artificial protein drinks. There needed to be something in the middle.”

Slate cofounder Josh Belinsky

After rolling out modern chocolate milks, Lubin and Belinksy found themselves building something other than their initial idea. “We realized the world needed a great-tasting, high protein, better-for-you drink, not just a healthy chocolate milk,” Lubin says. “Today, there’s even more demand for higher protein diets.”

The brand has expanded to include several different milks and coffees with varying protein levels, totaling 20 different products. No matter how large the slate becomes, one thing will always remain: immaculate protein ratios and real dairy. “We want the best-tasting products with the best macro ratio profile,” Lubin says.

Slate doesn’t just focus on boosting protein levels, but maximizing protein to calorie and protein to sugar ratios. “We have 42 grams of protein and 190 calories in our 15 ounce ‘Ultra’ can. Almost 170 of those calories are coming from the protein itself,” Lubin explains. “It’s naturally 80% casein protein, 20% whey muscle-building protein.” In general, some protein is not bioavailable, or able to be absorbed by the body, whereas protein from cows milk certainly is.

But none of it matters if it doesn’t get gulped down. Lubin knows taste is superior to any other factor in a successful product. “If people are drinking it simply for the protein, we’re just another supplement,” he says. “We want a drink that people look forward to because it tastes freaking delicious.”

Slate 20g protein lattes

The primary reason why Slate is able to achieve such impressive protein to sugar ratios is because the ultra-filtration process filters out not just lactose, but sugar, while maintaining milk’s naturally beneficial nutrients, a value that plant-based milk can’t provide. A2 dairy is another low-lactose option, but when Lubin and Belinsky unearthed ultra-filtered milk, the gates of possibility opened wide.

Whereas A2 milk comes from cows that are bred without a certain protein, ultra-filtered milk goes through its own unique process to concentrate the milk once it’s already retrieved. It’s particularly intriguing to Lubin personally, being lactose intolerant. “We always knew that our product was going to be lactose free,” he says. “Ultra-filtered is lower sugar, higher protein and lower lactose, even before you insert the lactase enzyme.”

Slate 20g protein chocolate milk

The macronutrient ratios that Slate achieves would not be possible with standard cows milk. “In our standard package, you would have 17 grams of sugar and only 11 grams of protein–too much sugar, not enough protein,” Lubin says.

Brands like Fairlife and Painterland Sisters also utilize ultra-filtered milk for lactose-free dairy products. While it’s still a somewhat unknown dairy option, ultra-filtered milk is becoming more familiar to the average consumer as these products gain market traction. “When we started, there was one small [manufacturer] doing ultra-filtered,” Lubin says. “That company is now the largest ultra filtered milk company in the country.”

Consumers today are craving the nutrients that real dairy provides, but want something more sensitive to the gut. Nielsen IQ (NIQ) data shows the US cows milk market valued at more than $12 billion and has been somewhat steady over the past several years, whereas the lactose-free dairy market stands at $2.7 billion, a 15% increase in the past year. Lactose-free, ultra-filtered milk specifically, although still a relatively smaller market, has seen a 30% increase in sales in the past year.

Slate sources its milk from dairy cooperatives who work with family-owned farms. The milk’s permeate, the byproduct from the ultra-filtration process, is upcycled into feed for animals and supplements water on the farms.

“Ultra-filtered milk is going to be the next generation of dairy,” Lubin says.

Maxx Crosby for Slate

Upon today’s announcement, Slate has raised more than $50 million to date since receiving its first check in 2018, including its $5 million seed round.

Angel investors in this round include the likes of actor Jonah Hill, DJ Diplo and rapper Ice Spice, of which Slate is her first consumer investment.

Slate is also the largest investment from Foundership, the new venture studio started by two people who know the modern dairy space well. Harrington and Klane sold Yasso to Unilever in 2023. Foundership emerges with an investment & advisory arm and a CPG incubator arm.

“A lot of the growth opportunities and challenges for Slate are things that we’ve seen in our own lives,” Harrington tells me. “They had a big idea in a big category, like what we had with Yasso in frozen dessert.”

Yasso itself even experienced a slight slump when plant-based milks started gaining more traction in the past 10 to 15 years, but that heyday is starting to drag along. NIQ data shows the alternative milk market (which is largely made up of almond milk) has not grown since 2023, experiencing a 4 to 5% decrease in each of the past two years, currently sitting at $2.3 billion.

“We stayed the course with Yasso and it proved to be the right decision. Slate has that opportunity ahead of them right now too,” Harrington says. “They have doubled growth every year.”

Slate "Ultra" 42g protein line

RiverPark Ventures is also an investment partner in Slate, participating in multiple financing rounds. ”Slate bridges the supplement lover with the everyday consumer,” Partner Spencer Krug tells me. “Protein today is so much more in vogue as a category than it was five years ago…Slate was very early to that movement.”

RiverPark, which was the first institutional investor in Sprindrift, points to Slate’s growing penetration in different sectors of everyday life and the way it embraces its cultural relevance, which is highlighted in its partnerships with figures like Maxx Crosby of the Las Vegas Raiders. Slate is also a brand partner of the UFC. Its CEO Dana White became a fan of Slate during his recent weight loss journey. “It feels like Slate is hitting an escape velocity,” Krug says. “A lot of their success has been folks organically reaching out to the brand.”

Slate’s diverse slate of investors understands the significance of building a product that speaks to modern consumer appetites. Other industry founders, including Peter Rahal of Rx Bar and David protein, Doug Bouton of Halo Top and Nick Rellis of Drizly are also investors. “Slate’s consumer is not only the person who’s working out and bench pressing at a gym, but also your everyday mother or kid who's on their way to class or someone who just works out once a week,” Krug says. “Better-for-you products are going to take over our grocery stores.”

Harrington emphasizes his affinity of investing in founders who possess the cultural and entrepreneurial understanding to escort a product from a humble idea to part of the zeitgeist. “Scaling any food or beverage brand takes grit, creativity, and execution. [Lubin and Belinsky] have proven that they have those,” he says. “Slate is going to be a household brand.”

Today’s most successful consumer goods create a brand that multiple demographics of Americans go out of their ways to incorporate into their lifestyles.

“Everyone that creates food should have the same goal…” Lubin says. “...to actually improve people’s lives.”