Rice is cooked badly more often than almost any staple, largely because a single method is applied to varieties that need different treatment.
The starch distinction
Rice starch consists of two molecules in varying proportions.
Amylose produces separate firm grains. Amylopectin produces sticky soft ones.
Long grain varieties are higher in amylose. Short grain varieties are higher in amylopectin.
Which is why one produces fluffy separate grains and the other clings, and why substituting one for another in a recipe produces a different dish.
Rinsing
Removes surface starch released during milling and handling.
Which reduces stickiness, and it is therefore appropriate where separate grains are wanted and inappropriate where clinging is.
Rinsing until the water runs mostly clear is the usual instruction, and two or three changes generally suffice.
Rice for risotto and similar dishes should not be rinsed, since the released starch is what creates the texture.
Soaking
Hydrates the grain before cooking, which allows it to cook more evenly and to elongate rather than break.
Which matters most for long grain aromatic varieties, where the characteristic length is part of the point.
Soaking reduces cooking time and therefore the water quantity, which is why recipes specifying soaking use less water.
The absorption method
Rice cooked in a measured quantity of water until it is all absorbed.
Which produces the most consistent results for long grain rice and depends on getting the ratio right for the variety and on the pan being properly sealed.
The steam does much of the cooking, which is why lifting the lid disrupts it.
Resting off the heat, covered, for several minutes after cooking allows moisture to redistribute and firms the grains.
The draining method
Rice boiled in abundant water and drained when done.
Which is more forgiving, since the exact water quantity does not matter, and it removes some starch.
It is the traditional method in several cuisines and produces excellent results for long grain rice, particularly where the rice will be layered with other components.
Ratios
Vary by variety, by whether the rice was soaked, and by the pan.
Which means a single ratio does not exist, and the reliable approach is finding the ratio that works with your rice and your pan and using it consistently.
Recording it once removes the guesswork permanently.
Common failures
Mushy rice generally means too much water or too long.
Hard centres generally mean insufficient water or insufficient time, and adding a splash and continuing covered usually rescues it.
Burnt bottom with raw top generally means heat too high, since the water boiled away before the grains cooked.
Sticky rice where separate grains were wanted generally means insufficient rinsing.
Reheating and storage
Worth a specific note for safety.
Cooked rice can contain spores that survive cooking and germinate at room temperature, producing toxins that further heating does not destroy.
Which is why cooked rice should be cooled quickly and refrigerated promptly rather than left standing.
Reheating should be thorough, and rice should not be reheated more than once.
Food safety authorities publish specific guidance, and it is worth following rather than relying on judgement, since the toxin does not affect smell or appearance.
Rice cookers
Worth mentioning because they solve the problem entirely.
They detect completion by temperature — while free water remains the contents stay at boiling point, and the temperature rises once it is absorbed, which triggers the switch.
Which is a simple mechanism that works reliably, and it is why even basic models produce consistent results.
More elaborate models add temperature profiles for different varieties, and the basic mechanism handles most requirements.
Pilaf method
Toasting the grains in fat before adding liquid.
Which coats each grain and produces a nuttier flavour and more separate result.
Aromatics cooked in the fat first flavour the whole dish rather than sitting on top.
Leftover rice
Chilled rice is firmer and drier, which makes it better for frying than fresh rice.
Which is why fried rice recipes specify day-old rice, and it is a genuine technical requirement rather than a thrift measure.
Brown and other whole grain rice
The bran layer slows water absorption, which is why cooking times are considerably longer.
Soaking helps substantially, and the draining method suits it well since the exact ratio is less critical.
Arsenic
Rice accumulates inorganic arsenic from soil and water more than other grains.
Rinsing and cooking in abundant water then draining reduces it measurably, which is one practical argument for that method.
Advisory guidance in several countries suggests limiting rice-based products for young children specifically, and the risk to adults from a varied diet is low.
Aromatics
Whole spices, bay, cardamom and similar added to the cooking water perfume the rice without appearing as a strong flavour.
Which is a small addition with a noticeable effect, and the whole spices are removed or left aside when serving.