Lu-Braised Firm Tofu

Tofu is generally attributed to the Han dynasty, with the earliest archaeological evidence from a Han tomb mural at Mixian, Henan (c. 25–220 CE) that some scholars interpret as depicting tofu-making equipment. Pressed tofu (dou fu gan) emerged as a distinct product when makers discovered that applying heavy weights after coagulation expelled enough whey to create a firm, sliceable block. Suzhou's lu zhi dou fu gan (brine-braised tofu curd) became the most famous regional variant, with at least a century of documented production; the writer Jin Shengtan, executed in 1661, reportedly told his son that 'peanuts and braised tofu eaten together taste like ham'—an early literary endorsement of the dish's satisfying depth. Shaoxing's fennel-spiced tofu dry is another historic variety.

A piece of lu tofu is firm enough to be picked up with chopsticks without crumbling. The outside is amber-brown from the soy brine, the inside slightly lighter. The five-spice aroma is present but restrained—a background warmth rather than an assertive punch. The tofu itself has a faint clean bitterness and a protein-dense, slightly chewy texture. It is food for concentrating on: plain, satisfying, and honest.

Pressed tofu has been mechanically dewatered to a protein content of about 15–20% (versus 8% for silken tofu), creating a dense matrix of coagulated soy protein that can withstand prolonged braising without disintegrating. During simmering at 75–90°C, osmotic pressure drives salt, soy sauce amino acids, and aromatic compounds from the brine into the tofu matrix, while water moves out. The key insight is that post-heat steeping (off heat, 30+ minutes) is more effective than continuous boiling for deep penetration: as the tofu cools, the protein matrix contracts slightly, drawing brine deeper.