Japanese A5 Wagyu Sirloin Filet

Most people associate Kobe beef with the name alone, but the Kobe Wine Beef Association represents something more specific: a documented feed program where cattle consume grape marc, lees, and other polyphenol-rich byproducts from Hyogo's wine industry. Polyphenols are antioxidants. In the animal, they reduce oxidative stress, which directly correlates with lower cortisol levels — and lower cortisol means more relaxed muscle tissue and finer intramuscular fat distribution. This is food science you can taste. The fat in this steak melts at a noticeably lower temperature than commodity beef, which is why a brief sear is all it takes.

The cut itself is worth understanding. The sirloin filet — carved from the short loin — is a naturally round, thick steak that's often overlooked in favor of the ribeye or strip. That's a mistake. It has less connective tissue than a ribeye, a tighter grain than a strip, and because it's not the tenderloin, it actually carries more beefy flavor alongside the rich fat. At BMS 12 — the maximum score on the Japanese marbling scale — every bite is dense with intramuscular fat that coats rather than overwhelms.

We also appreciate the nose print certificate for reasons beyond the novelty. In a market flooded with mislabeled and counterfeit Wagyu, this is a real traceability mechanism. Japan's beef grading and certification system is the most rigorous in the world, and this certificate is your proof of participation in that system.

Before You Cook

Pull the steak from the refrigerator 20–30 minutes before cooking and pat it completely dry. No oil, no seasoning yet — A5 Wagyu has enough intramuscular fat to be its own lubricant. Season with flaky salt only after the sear. Because the fat content is so high, you need far less heat and time than you're used to.

Recommended Methods

Cast Iron Sear (Recommended): Heat a dry cast iron skillet over medium-high until it just begins to smoke. Sear the steak 60–90 seconds per side. The fat will render quickly — don't push it past medium-rare or you'll lose the marbling effect entirely. Internal temp target: 125–130°F.

Sous Vide + Sear: Bag the steak and cook at 129°F for 45 minutes. Pat extremely dry after the bath, then sear in a ripping hot dry pan for 30–45 seconds per side. This method gives you edge-to-edge consistency on a thick cut like this.

Reverse Sear: Bring the steak to 115°F in a 250°F oven (roughly 20–25 minutes), then finish in a screaming hot cast iron. Best for those who want a slightly more rendered fat cap.

What to Avoid

Do not cook past medium-rare. At BMS 12, cooking further renders out the marbling you paid for.

Avoid high-smoke-point oils — the steak doesn't need them and they'll interfere with the clean fat flavor.

Skip the butter baste. The fat in this steak is already doing that job from the inside.

Resting & Slicing

Rest for 5 minutes tented loosely with foil. Because this is a thick, round cut, slice against the grain into ½-inch medallions to serve — this shortens the muscle fibers and makes every bite texturally effortless. A light finish of Maldon salt at the table is all you need.