following CA's prompt (and the willingness to believe if i could that the back of the chenab pack is not a load of old chalk) i made 2 batches of rice last night which we had for tea along with a few bhajis.
the Zebra is for me top notch so i cooked it as i've always done - weigh the rice, x2 weight of water, into pan, lid on, just as it comes to boil turn v.low (3/4 of setting 1 on electric hob), cook for 10mins (i normally optimise this over a number of go's within a range of 8 to 15 mins), off heat leave to stand for 5 mins.
the chenab has no room on the packaging for cooking instructions (see initial post). however following the Zebra cooking instructions and CA's prompt i cooked as follows: weigh rice, rinse x2, soak 30 mins & drain, x2 weight of water, the rest as per above.
as CA predicted the chenab did taste much better. the chalkiness had almost gone. the rice remained what i'd call "sticky rice" though and had differing texture across the grains whilst eating it.
the Zebra did not taste as good as the previous go when i rinsed and soaked it. however it did not disappoint and was what i call basmati rice. the aroma is not as strong as i've experienced with other brands. there was no stickiness at all, separate huge grains all of the same texture.
conclusions:
1) rinse and soak makes a difference but not essential
2) the zebra consists of 1 type of grain and is in the super class (patent)
3) the chenab is a mixture of grains. it needs rinsing and probably soaking to get the best out of it. i suspect that most rice in the shops is this type and although branded as basmati is hugely different to the best stuff.
pics chenab & zebra
nb there was some water in the base of the pan of both batches and i would normally up the low ht cooking on the next go by 1 min and see how it turns out