Burgers across three ground beef fat ratios (93/7, 80/20, 70/30), as experiments

Experiment 1: cook 15 g chopped lean flank steak and 15 g chopped beef fat side by side on the griddle; the lean meat releases water that steams at 212F and goes grey, the fat melts, shallow fries itself and browns.

Experiment 2: shape 170 g of 93/7 beef into a patty, and 135 g chopped chicken breast mixed with 35 g chopped beef fat into another; cook both and assemble with burger sauce, three pickles, shredded lettuce, onions and cheese for a blind taste test.

Experiment 3: shape 150 g patties of each mix, cook on the griddle to about 140F (60C), weigh, then squeeze between two deli containers and weigh the juices.

Experiment 4: cook one 80/20 patty in a ripping hot dry pan on the stove and poach another in water; only the pan patty browns, since water cannot pass 212F and browning needs above 300F.

Experiment 5: smash 85 g balls of each mix onto a ripping hot griddle with the press; let the crust form about 60 seconds, scrape and flip.

Final test: build three identically sized double smash burgers, one per mix, on a bun with burger sauce, thinly sliced lettuce, thinly sliced red onion and cheese between the patties.