Science Behind Different Color of Edible Bird’s Nest

Natural white nest:

Not all bright white nests are bleached because the nest natural color when it first produced by swiftlet is indeed bright white. This very white color can only be obtained when nest is harvested immediately after the bird produces the saliva.
When nests stay in the farm for a little bit longer, the color of the nest changes to more faded color. Therefore it is most common in the market to see Edible Bird’s Nest in faded white color. The natural bright color simply the hardest to get (strict harvest management).
Other factor that changes nest color is pollution. Nests harvested from polluted area tend to be dark gray, and wrinkle (when in dry condition). Some people concern of heavy metal contents (arsenic, mercury, led, cadmium) carried in the air. Small portions of Edible Bird’s Nest producers such as pristine farms are very particular about this. These companies usually do not compromise on quality by going far from cities, rather than choose operational convenience.
The fascination toward white color leads to a lot of ill practice like bleaching. This is absolutely not acceptable. Customer should be able to avoid such product. Although the color is similar with the nest harvested immediately (mentioned on 1st point), the substance of bleach nest is already destroyed.
Naturally white nest has smoothest and softest surface, creating a delicate texture when consumed. Bleached nest will breaks down easily when cooked during first 30 minutes.

Science Behind Different Color of Edible Bird’s Nest

Yellow nest/golden nest:

With the right microclimate condition in the farms/cave (humidity, temperature, soil condition, etc.), the original white nest will gradually change its color into yellow.
Yellow nest is preferred in certain culture because it symbolizes gold and prosperity.
Yellow nest takes longer to form in the farm. Usually it becomes faded yellow, but bright yellow as premium quality is rare because it need accuracy in farming.
Because it stays longer than white nest in the farms, yellow nest has tougher texture and thicker nest.

Red nest/blood nest:

Red nest is the most exclusive product in the some market. In China is has been feared for a high nitrite level, however this is not dangerous because such nitrite with very easily dilute when soak in the water.
In the bird’s house or cave, white nest change its color to yellow under optimum condition. It will further turn into red color.
It takes another 6 months for a Edible Bird’s Nest to gradually transition from white to red.
The red color does not come from the blood of a dying bird (Coughing blood). It is an absolute myth. Yellow and red color nest are simply byproducts of Edible Bird’s Nest protein content that reacts with the conditions of the surrounding.
Because Red nest mature in the farm, it has the thickest structure among other types. This texture is more elastic when consumed.