Biz Carson , FORBES STAFF  

Honey Butter Chicken, a Chicago restaurant, prepares for a pop-up delivery restaurant via Caviar in Oakland, California.

Inside the Forage Kitchen in Oakland, Josh Kulp scrolled through the 89 pre-orders that had already come in for his restaurant’s fried chicken, getting just a preview of what the weekend would be like.

Kulp, who co-owns Honey Butter Fried Chicken, a Chicago restaurant, had already shipped ahead his trademark honey butter. Two-thousand miles away from his home base, Kulp was taking a risk as he prepped his food to serve a new market in California with potentially different tastes.

“This feels like we’re operating a restaurant here,” Kulp said. “There’s a lot of unknown.”

As the competition between delivery companies heats up in a very crowded market, the next battleground is in the kitchen.

Food-delivery startups from DoorDash to Uber Eats to Postmates are all now experimenting with different ways to maximize a restaurant’s kitchen — and in turn, generate more customers and more orders for partner restaurants. The delivery companies’ tactics range from deploying mini kitchen trailers to renting out extra space at fairgrounds to launching online-only companies. In a competitive market estimated to be worth $30 billion, each company is trying to play to its strengths to make sure it is the first app that a customer opens when they’re hungry.

Back in Oakland, Caviar, a food-delivery startup owned by Square, had rented a catering space for Honey Butter Fried Chicken to set up its delivery-only pop-up for the weekend. The Chicago restaurant had been a loyal partner of its delivery service, so a Caviar manager enticed Kulp to try a weekend in the Bay Area and see if Honey Butter’s fried chicken appealed to taste buds across state lines.

Honey Butter Chicken’s famous chicken sandwich in Oakland, California.

It’s a strategy designed to play to the delivery company’s strengths, said Gokul Rajaram, Caviar’s lead at Square. Caviar has already tried offering exclusive menu items on its delivery service menu, and it’s frequently the only delivery partner for its restaurants. Offering a one-weekend-only pop-up restaurant has helped drive new customers for its service, Rajaram said.

The first time Caviar tried a pop-up restaurant in New York City with San Francisco-based Souvla, the delivery company saw 25% of the orders coming from new customers. When it came to Honey Butter’s delivery pop-up in Oakland, 23% of the orders were from new customers. The restaurant itself did 200% more deliveries on Caviar in the East Bay than it did for its Chicago location over the same weekend.

“People seem to value exclusive content,” Rajaram said.

The rise of the ‘dark kitchens’

While Caviar has tried limited weekend runs, other delivery companies like Postmates and DoorDash have opted to take longer-term leases. In Los Angeles, Postmates quietly leased a commissary kitchen space so its restaurants can reach new customers and sell even more. On the first day, Tatsu Ramen made 150 bowls of ramen in the first five hours. Now, multiple restaurants are working Postmates’ spare kitchen space and the company says it’s considering adding additional locations.

DoorDash opted to rent extra space from the Santa Clara Fairgrounds in San Jose, California. Its inaugural client was Bay Area pizza chain Little Star, which didn’t have a San Jose location. Instead, the chain has been cooking its cult-favorite deep dish pizza under a new brand name “The Star” out of the fairground kitchens to test if San Jose is a good market for expansion.

A chef makes a pizza for The Star inside DoorDash’s commissary kitchen.

The idea of creating “dark kitchens” or delivery-only spaces with no storefront isn’t necessarily new, but one that’s been slower to catch on among U.S.-based delivery companies.

In the UK, British delivery startup Deliveroo experimented for over a year with setting up prefab shipping-container kitchens called Rooboxes inside parking lots or tucked under freeways to make its delivery more convenient. It officially launched the dark kitchen concept in April 2017 under the moniker Deliveroo Editions. At the time, Deliveroo’s CEO called the launch of Editions “the biggest development in the market” since his own company was formed.

While the U.S. delivery companies have approached experimentation more cautiously, Deliveroo already has 106 different Deliveroo Editions kitchens operational across countries like the UK, Italy, Singapore, Hong Kong, Australia, United Arab Emirates and the Netherlands. The food is also going across borders. In October, Deliveroo announced that Italian pizza company Lievita would open its first out-of-country delivery offshoot in London.

The not-so-virtual restaurant

It’s no surprise that a rideshare company built on the premise of not owning the cars in its network has avoided leasing kitchen spaces. Instead, Uber’s delivery business, Uber Eats, has been running what it calls “virtual restaurants.”

These aren’t imaginary kitchens, but new restaurant brands that exist only in Uber’s app.

Rather than opening up a physical space, Uber Eats has been working with its restaurant partners to launch different kinds of restaurants from the kitchen space they already use. Elyse Propis, an Uber Eats program manager, said the experiment began earlier this year when the Hawaiian food poke started taking off as a popular meal that people were searching for on the mainland. There were only a few poke restaurants in Chicago. So Uber started by reaching out to Japanese and sushi restaurants to see if they wanted to try creating a poke-focused restaurant concept for delivery-only within the Uber Eats app.

“There’s essentially no upfront investment unless they need to purchase new ingredients,” Propis said. “It’s incredibly low-risk.”

Uber uses data from its app – from people typing in things like “chicken” in the search bar to popular items in surrounding areas – to help pinpoint what customers are looking for. Some virtual restaurants make similar food at a lower price point by switching up ingredients. Other times they opt for experimenting with an entirely new cuisine, like a pizza restaurant in Chicago making fried chicken wings.

“I think it goes back to us viewing our business as ‘How do we use the data that we have to allow our restaurateurs to utilize the spare kitchen capacity that they already have?'” said Jason Droege, the head of UberEverything. “I think that’s something we’re really good at.”

GrubHub has also experimented with the virtual restaurant concept, even as early as 2015 when it did a special pop-up weekend for a soup and salad restaurant. More recently, it also worked with restaurants to develop poke bowl virtual restaurants, the company cited as one example. But GrubHub too has largely ignored the commissary kitchen model except for a rumored investment in a company that operates several restaurant concepts in one dark kitchen space.

One advantage over leasing brick-and-mortar is simply the cost: there’s no lease to take on. While some companies like Caviar are absorbing the weekend cost, others like DoorDash are still figuring out which business model (subleasing or charging a higher commission) is best.

While renting a space isn’t totally ruled out in the future for Uber, Droege said he believes the better investment is on product development and data analysis than getting into a leasing business.

“I think we’re making a good-size investment in it from an experimentation standpoint,” Droege said. “Are we taking down leases? No. Are we getting into the real estate business? No. But I think if you’re keeping the customer experience in mind there’s multiple pathways to get to good quality selection at a good price.”