How Do Bees Make Honey? The Journey from Nectar to Honey

A spoonful of honey on your breakfast table is the product of weeks of hard work by thousands of bees. A beehive is an extraordinary factory that combines sugar chemistry, airflow engineering and the ability to communicate by dancing. Its raw material is a sweet reward flowers offer to bees: nectar.

It all starts with a flower

Flowers produce nectar to attract the insects that pollinate them. Nectar is a sweet liquid made mostly of water, containing several sugars, above all sucrose. Depending on the plant, nectar is usually 50–80% water.

Forager bees, which work outside the hive, suck up nectar with their long, tube-like tongues. They do not digest it but store it in a special compartment called the honey stomach (or crop). A forager can carry close to her own body weight in nectar — and may need to visit hundreds of flowers on a single trip to fill up.

Turning nectar into honey

1. The chemistry begins

Even on the way back to the hive, the forager adds enzymes from her glands to the nectar. The most important are:

• Invertase, which splits each sucrose molecule into two smaller sugars, glucose and fructose. These are easier to digest and crystallise less than sucrose.
• Glucose oxidase, which converts a small amount of glucose into gluconic acid and a little hydrogen peroxide. These two substances make honey acidic and resistant to microbes.

2. Passing it on

Back at the hive, the forager hands the nectar over to house bees mouth to mouth, a behaviour called trophallaxis. The house bees hold and work the nectar for a while, adding more enzymes and spreading it out in thin droplets to drive off some of the water.

3. Evaporation

The nectar is then placed in comb cells, still very watery. If it stayed that way it would ferment and spoil, so the bees turn the hive into a giant drying room:

• nectar is spread thinly across the cells to increase its surface area;
• hundreds of bees fan their wings at once, creating a strong airflow through the hive;
• the hive is kept at around 35 °C, speeding up evaporation.

The process can take days. In the end, the water content falls from around 70% to about 17–18%.

4. Sealing

When the honey is ripe, the bees cap each cell with beeswax, secreted as tiny flakes from special glands on the abdomens of young worker bees and chewed into shape. Sealed honey becomes the colony’s food store for winter and for times without flowers.

How do bees tell each other where the flowers are?

When a forager finds a rich patch of flowers, she returns to the hive and tells the others where it is. She does this with the waggle dance, discovered by the Austrian scientist Karl von Frisch, who won a Nobel Prize for it in 1973.

The dance works like this:

• Direction: the bee walks along a straight line on the vertical comb, waggling her abdomen. The angle between that line and “straight up” shows the direction of the flowers relative to the sun. If the line points 40 degrees to the right of up, the flowers lie 40 degrees to the right of the sun.
• Distance: the longer the waggle run lasts, the further away the flowers are.
• Quality: the more vigorously and often she repeats the dance, the richer the source.

The dance was debated for a long time; some scientists thought bees simply followed scent. In a 2005 study published in Nature, researchers fitted bees that had watched a dance with tiny radar transponders and showed that they really did fly in the direction and distance the dance described.

Why doesn’t honey spoil?

Stored properly, honey is one of the few natural foods that can keep for years. There are several reasons:

Honey does absorb moisture from the air, though. If the jar is left open, its water content rises and it can ferment — so keep it sealed.

Why does honey crystallise?

Many people believe crystallised honey is fake. It is not. Honey is a supersaturated sugar solution: it holds far more sugar than could normally dissolve. Over time the glucose crystallises and the honey sets.

• Honeys high in glucose, such as rapeseed or sunflower honey, crystallise quickly.
• Honeys high in fructose, such as acacia honey, stay runny for a long time.
• Cool conditions (about 10–15 °C) speed up crystallisation.

Standing crystallised honey in warm water (below 40 °C) makes it runny again. Very high heat damages its enzymes and aroma.

Why does honey vary in colour and flavour?

The colour, flavour and aroma of honey depend on which plants the bees visited. Acacia honey is almost colourless and mild; chestnut honey is dark and slightly bitter. Some honeys, such as forest or honeydew honey, are made not from nectar at all but from the sugary secretions of insects that feed on tree sap.

Why do bees matter?

Honey bees do far more than make honey. They play a major role in pollinating many fruits, vegetables and oilseed crops. Yields of apples, cherries, almonds, melons and sunflowers depend heavily on bees.

In recent years bee colonies around the world have suffered serious losses. Scientists attribute them to a combination of factors including parasitic mites, diseases, some pesticides, poor nutrition and climate change. Protecting bees matters not just for honey but for food security.

In short

Honey bees transform nectar from flowers using enzymes, pass it from bee to bee in the hive and fan their wings to evaporate most of its water. When the water content falls below about 18%, they seal the cells with wax. Thanks to its low moisture, high sugar and acidity, the resulting honey hardly ever spoils. And bees tell each other where the best flowers are with the waggle dance, using the sun as a compass.