How do you make sugar water for hummingbirds?

One part plain white sugar to four parts water, stirred until it dissolves, cooled before it goes in the feeder. That's it. No red food colouring, no honey, no brown or raw sugar - honey in particular grows mould fast. The bit that actually matters is changing it: every couple of days when it's hot, maybe weekly when it's cool, and rinse the feeder with hot water each time. Cloudy nectar means it's gone off.