Jiaotuan Stirred Paste

Jiaotuan is a household food of the Wei River valley in Shaanxi and the loess country of northern Shaanxi, born of stretching coarse grain — corn, buckwheat, sorghum, or potato — when fine wheat flour was scarce. Its exact origin is unrecorded. A widely repeated folk story credits Zhuge Liang with inventing it while his army was encamped at Qishan in Shaanxi during the Three Kingdoms period, supposedly calling it 水围城, but this is local legend rather than documented history. What is real is the regional division of grain: the Guanzhong plain makes it chiefly from cornmeal, northern Shaanxi prefers buckwheat for a chewier, more flavorful paste, and parts of Gansu and southern Shaanxi make a potato-starch version. It carries the affectionate nickname 哄上坡 ("fools you up the slope") because, being almost pure starch, it digests fast and leaves you hungry again before you have climbed the next hill.

Hot from the pot in 水围城, the paste is soft and slippery, almost custard-thick, and you pinch off a coral-sized piece with the soup so it slides down barely chewed, sour and warming from the 浆水. Cooled and sliced, it turns firm and faintly springy, cool against the tongue, the bland corn carried by sharp garlic, the sour bite of vinegar, and red chili oil. Done well it is glassy-smooth all the way through with not a single raw lump and a clean, elastic body that holds its shape. Done badly it is grainy and lumpy from too little stirring, or it tastes of scorched, half-raw flour, or it slumps into a thin gruel that will not set because the flour-to-water ratio was off.

Everything depends on prolonged one-direction stirring while heating. Cornmeal is mostly starch; sprinkled slowly into boiling water and stirred constantly, the starch granules swell and burst, releasing chains that hydrate and lock into a continuous gel — full gelatinization — which is what turns loose flour into a smooth, cohesive, elastic mass. Adding the flour in a thin stream and stirring always one way keeps the granules separated so they hydrate evenly instead of clumping into raw lumps; the stirring also works the swollen starch into a stretchy network, which is why the count of strokes (locals speak of stirring scores of times) tracks with how chewy the result is. Low, steady heat over roughly half an hour cooks the starch through without scorching the bottom. Once cooled, the gel sets firm enough to slice, as the gelatinized starch partially re-orders (retrogradation) and stiffens. The accompanying 浆水 is itself a ferment — flour-water and vegetables left to sour for a few days on lactic-acid bacteria — and its acidity cuts the starch's blandness.