Making hummingbird nectar is easy – it’s a simple ratio of sugar to water, and refill the feeder. But is it really easy after all? There’s great debate over whether or not sugar water for hummingbirds needs to be boiled.

Why Boil Nectar?

There are three main ideas behind boiling nectar for hummingbirds.

1. Boiling removes impurities from the water, thus making it safer for hummingbirds.
2. Boiling sterilizes the water and minimizes contamination so it will not ferment as quickly.
3. Boiling makes it easier for sugar to dissolve so that nectar can be made more quickly.

Each of these ideas has some merit, but perhaps not as much as many birders may realize.

Does Boiling Remove Water Impurities?

Different water sources can have a wide range of contaminants and impurities, from bacteria, parasites, and microbes to heavy metals, chemicals, dirt, chlorine, lead, pesticides, herbicides, dissolved gasses, and other compounds. Municipal tap water is treated and filtered before being used, and a myriad of tests are frequently run to ensure the water is safe to drink. That does not mean the water is 100 percent pure, but only that the levels of potential impurities are not considered dangerous for human consumption.

Hummingbirds are not humans, of course, and their tolerances and sensitivities to different water contaminants may be far different than ours (though very little authoritative research has been done in this area). In general, however, wildlife rehabilitators, including those who work closely with hummingbirds, agree that tap water is typically safe for hummers.

Boiling, however, will not remove most impurities from water. When water reaches a rolling boil (212 degrees Fahrenheit, or 100 degrees Celsius), dissolved gasses will be removed, and living organic contaminants – bacteria, parasites, and microbes – will be killed. Other impurities, however, will remain in the water. If the water is heavily boiled for a long period, these remaining impurities may even be further concentrated and could present a greater risk when the water is consumed (though this is unlikely).

It is important to recognize that the levels of impurities in tap water are so very miniscule that they do not generally present a significant risk for hummingbird nectar, boiled or not. Therefore, boiling to remove impurities is not necessary.

Boiling to Reduce Fermentation

Fermentation occurs when the sugar in hummingbird nectar is consumed by microbes or bacteria. As those organisms digest, the sugar is converted into different byproducts, such as lactic acid and alcohol. If there are no microbes or bacteria in the nectar, there will be no organisms to consume the sugar and cause fermentation. Because boiling water will kill microbes and bacteria, it will inhibit fermentation and the nectar will stay fresh for longer.

This sounds ideal, but it is critical to remember that the nectar will only remain fresh and sterile so long as it is not touched by any contaminated objects. A hummingbird’s bill, however, is a contaminated object.

Hummingbirds visit a wide variety of flowers and feeders throughout the day. They wipe their bills on branches, twigs, and leaves, preen through their own feathers, collect nesting material, and eat insects. All of these actions put microbes and bacteria on their bills and tongues. When a hummingbird then dips its bill into a hummingbird feeder and licks at the nectar, some of those microbes and bacteria wash off, and the nectar is now contaminated.

Take note of that again – as soon as a hummingbird sips from a feeder, bacteria and microbes are introduced, and any benefit from boiling the nectar is lost. Therefore, boiling the nectar before filling a feeder is unnecessary, as the nectar will be contaminated immediately when a hummingbird visits.

Boiling to Help Sugar Dissolve

Warm liquids dissolve crystals more quickly, and boiling water will more quickly dissolve sugar to make hummingbird nectar. Yet we must consider the saturation of the sugar water solution to determine if this has any benefit for making hummingbird nectar.

The preferred hummingbird nectar recipe is one part sugar to four parts water. Assuming you are making one cup of nectar, you will then use one-quarter cup of sugar.

• One cup of water = 236 milliliters
• One-quarter cup of sugar = 50 grams

At typical room temperature (68-72 degrees Fahrenheit or 20-22 degrees Celsius), one cup of water will dissolve roughly 76 grams of sugar (see “An Introduction to Chemistry: Supersaturation“). This is far more than the sugar necessary for the proper nectar recipe. Heating the water will dissolve more sugar, yes, but there is no need, as increasing the water-to-sugar ratio is not recommended for making hummingbird nectar.

As an alternative to heating the water to dissolve the sugar, you can simply agitate the water by stirring or shaking. This will help disrupt the sugar crystals, allowing it to dissolve rapidly, no extra heat needed.

So What Does Boiling Do?

The only thing boiling water to make hummingbird nectar will do is it will – very slightly – help the sugar dissolve more quickly. Yet it is also recommended that you only refill hummingbird feeders with cool nectar. The time you save heating the water in order to save a few seconds for dissolving the sugar will simply be spent waiting for the nectar to cool again so you can refill the feeder. Thus, you haven’t really saved any time at all, and in fact may need to wait even longer for very hot nectar to cool sufficiently so feeders can be safely refilled.

Do I Boil My Hummingbird Nectar?

I do not boil the water I use to make hummingbird nectar, and I never have. My hummingbirds have not shown any disdain for unboiled nectar, and they still happily sip away at my feeders every time they are refilled.

I do, however, slightly warm the water I use to make nectar, using a stainless steel pot and stirring in the sugar with a metal spoon (as opposed to the wooden spoons I use for cooking, which may have some lingering residue even after cleaning). This only makes it easier to dissolve the sugar quickly, and the nectar cools off as I reassemble the hummingbird feeder.

If you want to boil the water you use for hummingbird nectar, go right ahead. It isn’t really doing anything to benefit the birds, but unless you’re boiling the water down to dregs (which would completely disrupt the water-to-sugar ratio), you aren’t doing any harm either, and the hummingbirds will appreciate both boiled and non-boiled nectar.