What does "It was not Paati's sambar" suggest?

When Ananya decided to write down her grandmother's recipe for sambar, she came armed with a notebook, a measuring cup and a set of spoons.

"How much toor dal?" she asked.

"Enough," said Paati.

"Enough is not a measurement, Paati."

Paati considered this. She scooped up the dal in her cupped hand, looked at it, poured a little back into the tin, and tipped the rest into the pot. "That much," she said.

Ananya measured what was left in the tin, subtracted it from what had been there before, and wrote down "three-quarters of a cup". She felt quite pleased with herself.

It went on like that all morning. The tamarind was "the size of a small lemon". The salt was "until it tastes right". The sambar powder was "a good spoonful, not a greedy one". Ananya measured, weighed and wrote, and by lunchtime she had two full pages of notes.

The next Sunday, she followed her notes exactly. The sambar was fine. It was, everyone agreed, perfectly good sambar.

It was not Paati's sambar.

When she told her grandmother, Paati laughed and took her hand. "You wrote down my hands," she said. "You did not write down my tongue. That, you will have to cook for twenty years to learn."