No matter how you slice it, french fries are delicious and almost universally loved.

You might have a preference when it comes to shape and size – shoestring, crinkle-cut, or steak, for example – but when it comes down to it, there’s not a single one that’s really bad.

If you’re looking to fry up the perfect specimen, though, science does have some good advice.

First up, you’ve got to choose the right potato.

People can argue about which variety is the absolute best, but most agree that a high starch content like you’ll find with a russet will fry up crisper than waxy varieties like a Yukon Gold or a red-skinned one.

Potatoes are classified as “waxy” or “floury/starchy,” and the latter type is lower in sugar and moisture content, too, which is important. If you’re at the grocery store, these will be a King Edward, Maris Piper, and Russet varieties.

Next up, should the fries be thick or thin? What shape is best?

Thick-cut fries may have a lower fat content, since they have a lower surface area, but otherwise, this comes down to a personal preference – even if you truly believe waffle fries should be a contender.

And what oil should you choose?

BBC Food says that science actually has an answer for this one, and there’s a clear winner.

“When you heat oil during cooking – deep frying, shallow frying, sautéing, or roasting – the molecular structure of the oil breaks down through oxidation. This produces byproducts called lipid oxidation products, some of which may potentially be toxic. This is more likely at higher temperatures and with frequent reheating.”

You want an oil with a high smoke point, which rules things like olive oil out. Highly processed oils have the highest smoke points, so you’ll want to stay away from all of the unrefined sorts for the best fry.

Peanut oil, vegetable oil, or canola (rapeseed) oil are going to be the best choices, hands down.

What about the best method to choose?

Veronique Greenwood of BBC Future says that many cooks actually agree on this one.

“Most cooks and food scientists agree that the best chips are fried twice. The first step is at a lower temperature to ensure the center is cooked through and gets nice and fluffy; then the second is at a higher temperature to crisp up the outside – made possible thanks to all the starch in our floury potatoes.”

Your oil should be around 300°F for your initial fry, and between 356°F-425°F for the final one.

What about using your air fryer?

A 2015 paper concluded that although air-fried french fries were lower in fat and healthier altogether, they were pretty much no one’s favorite.

Sorry about that.

But listen. You probably won’t have the capacity to do the perfect fry every time.

At least you know how, though.

Happy frying!

If you found that story interesting, learn more about why people often wake up around 3 AM and keep doing it for life.