Culver's vs Steak 'n Shake.

Two Midwestern institutions. Both diner-format. Both founded in the American heartland (Steak 'n Shake in 1934 Illinois; Culver's in 1984 Wisconsin). Both serve fries that are fundamental to their brand identity. And as of January 2025, the two chains diverged sharply on what's in the oil — Steak 'n Shake switched to 100% beef tallow; Culver's did not.

This comparison is unusual among Frypedia's pairings because it's time-sensitive. If you'd eaten at both chains in 2024, the fries would have been similar: vegetable-oil-fried, mid-Midwest flavor profile, clean enough for vegetarians. By 2026, they're not comparable anymore. Steak 'n Shake is in the Tallow Club; Culver's is a standard vegetable-oil regional. A single operational decision in early 2025 changed the comparison entirely.

The January 2025 switch.

In January 2025, Steak 'n Shake announced it was moving from a soybean oil blend to 100% beef tallow, with chain-wide rollout completing by late February. The switch was framed in the chain's communications as a return to "real food" and a nod to the 1950s diner heritage that the brand has always leaned on. It also came at a moment when seed-oil skepticism was peaking in American wellness culture, and when Steak 'n Shake was several years into a difficult financial stretch. The tallow switch was both an operational change and a brand positioning move.

Steak 'n Shake is now the only major chain on Frypedia that has switched from vegetable oil to animal fat specifically during the 2023-2026 seed-oil-panic window. Every other Tallow Club member (McDonald's, Bojangles, Portillo's, Smashburger) either has been in tallow for decades or chose tallow at founding.

Culver's has made no comparable switch. As of April 2026, Culver's still fries in refined canola oil, and shows no indication of changing. The chain is profitable, growing, and has no strategic reason to overhaul its kitchen.

What this means for the comparison now.

Before the switch, both chains served vegetarian-safe fries. After the switch, they don't. Steak 'n Shake fries are now non-vegetarian, non-vegan, non-kosher, and caution-for-halal. Culver's remains vegetarian-safe (though the shared fryer makes it caution for celiac and dairy-free).

The saturated fat numbers also diverged sharply. Medium Culver's: 2g saturated fat. Medium Steak 'n Shake (post-switch): 9g saturated fat. That's a 4.5x difference, and it's entirely the tallow doing the work. If you're watching saturated fat for cardiac reasons, Steak 'n Shake's new formula is a meaningful step backward. If you're explicitly seeking animal-fat-cooked fries for flavor or cultural reasons, Steak 'n Shake is now one of a handful of places in America that will give you that.

The cut matters too.

Culver's runs a medium-crinkle cut. Moderate surface area, good sauce-holding capability, predictable crispness. Industry standard for the category.

Steak 'n Shake runs a very thin shoestring cut. High surface area, rapid cooking, shatter-crisp exterior. The shoestring cut is actually why the tallow switch matters more at Steak 'n Shake than it would at, say, a thick-cut-steakhouse-fry chain — a shoestring fry absorbs much more oil per gram than a crinkle fry. Changing the oil at Steak 'n Shake changes the product more dramatically than changing the oil at a thick-cut chain would.

The shared-fryer caveat, on both sides.

Neither chain runs a dedicated fryer chain-wide. Culver's fries share oil with cheese curds, onion rings, chicken tenders, butterfly jumbo shrimp, and pork tenderloin — one of the most crowded shared fryer situations on Frypedia. Steak 'n Shake's fryer situation varies by location; some stores run a separate fryer, others don't. Beef tallow in the oil is, separately, its own issue regardless of cross-contact.

For celiacs, neither chain is safe. For dairy-free diners, neither chain is safe. For vegetarians, Culver's works and Steak 'n Shake doesn't (as of 2025).

The verdict.

If you're vegetarian, vegan, or kosher, Culver's is the only option between the two, as of 2025. Steak 'n Shake's tallow switch took them out of contention.

If you're watching saturated fat or calories, Culver's is lighter across every metric.

If you specifically want an animal-fat-cooked fry, Steak 'n Shake is now one of five chains in America that will give you one, and arguably delivers the strongest flavor signal of the five (the shoestring cut absorbs more tallow per bite than any thicker-cut chain).

If you're celiac or dairy-free, both chains are caution. Neither is safe.

If you're nostalgic for Steak 'n Shake the way it used to be, we have bad news: the fry program changed in early 2025, and it's not going back. What you remember is a different product than what you'll get today.

See the full writeups: Culver's · Steak 'n Shake