grating and strainig is essentially what a juicer does though more efficient. if you have a juicer, i would recommend this method and no heat as the juicer will do all the straining for you and the raw (uncooked/unheated) juice seems to retain its zing a great deal longer and better ( i think the sugar may act as a preservative). also, raw ginger juice is so potent that a little mellowing is not necessarily a bad thing. try making a small amount (all you are likely to get from a pound or two) and tasting it over several days. when buying your ginger look for the smoothest shiniest wettest seeming ginger. if you have access to a widely varied market, baby ginger is an excellent option as well and will produce more juice pound for pound. for extra freshness , try germinating your ginger in the fridge by wrapping in a moist towel.