Two cooks following the same sambar recipe produce noticeably different results. The dish has several independent variables, and each one moves the outcome in its own direction.
The spice blend is not standardised
The ground blend at the centre of the dish is a household preparation, with proportions varying between families and often between generations of the same family.
Roasting the components before grinding changes them substantially, and how far that roast goes is a judgement made by smell rather than by time.
A blend roasted darker gives a heavier, nuttier dish; one roasted lightly stays brighter and sharper, from the same ingredient list.
The souring agent has a range
Tamarind varies in strength, age and how it was extracted, so the same stated quantity delivers different amounts of acidity.
Cooks judge by taste rather than by measure, and the level each considers correct differs, which alone accounts for much of the variation between versions.
Acidity also interacts with the pulses, since adding it early slows their softening, so timing changes texture as well as taste.
The pulse is cooked to a chosen consistency
Pigeon peas can be cooked until they hold their shape or until they collapse completely into the liquid, and both are legitimate.
That decision determines the body of the dish, since a fully broken pulse thickens the whole thing while an intact one leaves it thinner.
Whether the cooked pulse is mashed, and how thoroughly, is a further step that recipes frequently leave unspecified.
Vegetable choice changes the sweetness
The vegetables in a sambar contribute their own sugars and their own water, so a version built on drumsticks tastes different from one built on pumpkin.
Some release moisture and thin the dish; others absorb liquid and thicken it, which shifts the balance of everything else.
Seasonal availability meant this varied through the year in any given household, so even one cook's sambar was never a fixed thing.
The finishing step sets the first impression
The spices fried in fat and poured over at the end are the first thing smelled, and they vary in composition and in how far they were taken.
Curry leaves, dried chilli and mustard seeds each behave differently, and the fat used carries its own character into the dish.
Which is why two bowls with nearly identical bodies can read as different dishes from the first spoonful, before the underlying variables register at all.