Cuisson du riz

Usually, following instructions on the package works, however sometimes it does not, furthermore, rice in bulk has no instructions.
Here are a few pointers based on experience that I use when cooking rice. For conversion from cups to grams use
Rice and Rice Flour Conversion Calculator

Long grain parboiled rice (10 mn):
Box says 4 cups chicken stock for 2 cups rice.
In theory 1 cup rice is 185 g and 1 cup water is 235 g.
My measurement give: 195 g and 1 cup water = 225 g.
So 195 g rice and 450 g liquid for 2 servings, verified OK!

Box instructions do not work:

Prepare  the liquid (salt water or stock), bring to a boil, add the rice.
Cover and simmer (no! small boil!!!) for 10 mn (no! more like 15) until liquid absorbed,
wait 5 mn no lid to rest. Spread with a fork, add a couple knobs of butter.  Verified OK!

riz basmati:
package says 300 g rice (washed to remove all starch) and 4.25 dl bouillon or salt water (4 persons).
Bring to a boil and let sit covered for 15 mn. This does not work.
In  theory it should be 300 g rice and 500 ml stock.
As soon as it starts to boil, lower heat to barely simmer and cover for 15 mn. Do not open the lid.

use 700 g rice for 12 servings and 1,166 g liquid

for 750 g rice, use 1.25 l stock