Salt and kneading build the frame
Udon dough holds salt and water, and gets kneaded hard. This builds a strong gluten net. The net gives the noodle its spring.
The bite comes from a water gap
Boiling soaks the outside first. The surface turns soft and slippery. The core stays drier and firm. Your teeth feel both at once.
Time erases the gap
Water keeps moving toward the dry core. After about 10 minutes in broth, the noodle feels even and soft. Freezing right after boiling stops that movement.
Shunta says:
Bite one noodle at 1 minute and one at 10 minutes. You can feel the gap close.
