Successful hummingbird nectar contains 4 parts water to 1 part white sugar. Heating the sugar solution slows fermentation, kills mold and bacteria, and helps the sugar dissolve.
In order to successfully attract hummingbirds and provide a healthy food source, it is best not to deviate from the standard recipe. This nectar recipe is similar to nectar found naturally in flowers. Weaker solutions do not reliably attract hummingbirds, and stronger solutions cause problems for the birds' digestion. Similarly, ingredients such as honey, brown sugar and molasses are indigestible to hummingbirds. These ingredients also spoil quickly, leading to the growth of dangerous mold or bacteria.
It is not necessary to add red dye to hummingbird nectar. While contemporary red dyes are not toxic to humans or animals, the red feeding ports of most feeders suffice to attract birds. Red ribbons or lawn ornaments placed near a hummingbird feeder help attract birds. Even better is the addition of red flowers to the landscape. These both attract birds and provide an extra food source.
While nectar, both natural and artificial, is a quick source of energy, even natural nectar is not highly nutritious. Like most animals, hummingbirds need proteins, fats and vitamins in their diet, which they obtain by foraging for insects.