For many, the idea of blueberries being blue is a simple truth. But it turns out that this is a misconception.
In reality, blueberries aren’t blue at all. Instead, their color is a result of an optical illusion.
The ‘trick of the light’ behind blueberries’ color
Blueberries’ blue appearance is not what it seems.
Scientists at the University of Bristol have uncovered the truth.
They discovered that the color we see is due to a “colorless, two-micron-thick wax layer” covering the berry.
This wax has an intricate microscopic structure that interferes with light, making the berry appear blue to the human eye.
Blueberries’ evolutionary trick to attract birds
The reason for this visual effect is believed to be evolutionary.
The blue-like color is meant to attract frugivores, such as birds, to the fruit.
However, the underlying pigment is actually more red. This optical illusion is similar to the phenomenon seen in hummingbird feathers, which also appear blue but are not.
The discovery was made when scientists removed the wax from blueberries, recrystallized it, and studied it in a lab.
They found that the wax reflected both blue and ultraviolet light.
While the blue light is visible to humans, ultraviolet light is not, contributing to the berry’s blue appearance.
What this discovery means for the blueberry world
Radio host Rachel Burden shared this discovery with her audience on Radio 5 Live Breakfast, sparking surprise.
Her co-host, Chris Warburton, was astonished when he learned that blueberries aren’t blue. Both agreed that the fact was “mind-blowing” and “exciting.”
Rachel added: “It’s thought that the fruit has evolved to look like this, to show off this blue-ish colour, to entice frugivores such as birds.
The underlying pigment is more red-ish, but this is a trick also. It’s the same sort of trick that hummingbirds have in their feathers, which apparently aren’t actually blue either.”
Rox Middleton, a research fellow at the University of Bristol, explained that the blue color in blueberries cannot be extracted from the juice.
This is because it is not present in the pigmented juice but in the berry’s wax.
This revelation adds a new layer of understanding to the fruit’s unique appearance.
While we’ve long thought of them as blue, science reveals their color is much more complex, driven by evolutionary needs and microscopic details.