The Potato Variety In-N-Out Chooses For Its Signature Fries

Ask any In-N-Out fan what makes this chain stand out in a sea of fast food giants, and you'll get an earful. For some, it's all about the fresh, never frozen, beef, and for others, it's the simple but endlessly customizable menu. There's also the fact that all the food is made to order, even the fries, which are also cut fresh on-site. It's all about getting the basics right, including choosing the right potatoes for the job, which is perhaps why Julia Child was a big fan of In-N-Out. Many believe the obvious choice is Kennebec, which is prized for frying. Others point to Russet Burbanks, which are a similarly starchy favorite.

The company has maintained radio silence on the matter, which might suggest that there's more than one potato variety at play — or that they're both wrong. But both fan theories are credible in their own ways, and the choice actually plays a big part in the consistency of each french fry.

Unlike its fast food competitors, In-N-Out can list the ingredients for its french fries on one hand. The company prides itself on filling those iconic red-and-white sleeves with potatoes fried in sunflower oil and sprinkled with a mix of salt and pepper. But when the food is this simple, there's a lot riding on the quality of the potato.

That's perhaps why the company is rumored to use Kennebec potatoes for its fries. These medium to large white potatoes have a high starch and sugar content. They're often made into french fries because they fry up crisp (they're used in lots of varieties of commercial potato chips, for example) and have a clean potato taste and a fluffy texture. Kennebecs are also available year-round, which makes them an attractive choice for a busy burger restaurant chains that pride themselves on consistency.

As for the evidence, much like tracking down the source of a product at Costco, it's all very much word of mouth. Specialty Produce, a supplier in San Diego, California, mentions In-N-Out on its website description of Kennebec (though in the past tense), and commenters on Reddit have also claimed that Kennebec is the variety of choice.

If you're not convinced by the admittedly shaky evidence that the fries are made with Kennebec potatoes, it's worth considering the case for Russet Burbank instead. Russet Burbank is a much more widely recognized variety in the United States because it's commonly sold in grocery stores. They're large, white potatoes with a thick brown skin and a mealy texture that gets fluffy when cooked. These are typically used for baked potatoes, but they also make great fries. In fact, russets are the potato McDonald's uses for its fries. 

The biggest clue in favor of Russet Burbank comes from a site called In-N-Out Menu, a website dedicated to the restaurant's offerings but not officially affiliated with the brand. It states, unequivocally, that the fries are made with Russet Burbank potatoes. As with the Kennebec, there are also some rumblings on social media in support of Russet Burbank, but again, nothing has been confirmed by In-N-Out.

Both are strong contenders for the face of In-N-Out's poster potato, but if we had to guess, the best explanation is that In-N-Out won't confirm a single type because produce availability can fluctuate. Both varieties make decent fries, and once you start ordering off In-N-Out's secret menu, they start piling on American cheese, grilled onions, and spread for an Animal Style order that makes it really hard to tell the difference.