How to select bird's nest

A gift of bird's nest is commonly perceived as a gift of good health. But how much do you really know about this Chinese delicacy?

To start off, edible bird's nest is produced by three species of swiftlets - white-nest, black-nest and grass-nest.

These birds use a glutinous saliva secretion to construct their nests, which are prized by the Chinese, who believe they can boost one's complexion and immune system.

Herbalist Ang Lai Chye, a retail supervisor at Eu Yan Sang's Paragon outlet, said between 85 per cent and 97 per cent of the nest built by the white-nest swiflet contains salivary glutinous strands, so it is considered the "cleanest" nest among the three species.

The black-nest swiftlet, on the other hand, mixes feathers and plant materials with its salivary secretion to build its nests.

Grass-nest swiftlets, as the name implies, build their nests with grass and salivary secretion. For these two species of swiftlets, only 5 per cent to 15 per cent of their nests contain salivary strands, though these nests are also eaten.

A swiftlet builds its nest to lay eggs and house its young till they are ready to take flight.

Licensed harvesters must ensure that nests are collected only after they have been abandoned by young swiftlets, said Mr Ang.

That is why harvesting time coincides with the swiftlets' breeding season and ends before nesting begins, he added.

Bird's nest can be harvested once or twice a year. The first harvest may take place between November and March, when there is a surplus of rain and food. Industry players regard nests built during this period to be of the best quality, Mr Ang said.

The second harvest is carried out from late July to early September, with each harvest typically lasting about 10 days.

Bird's nests can be found in caves on cliffs, or in purpose-built houses. While their nutritional content is similar, house nests are cleaner, with fewer impurities and feathers than nests built in caves. They also expand more quickly when soaked in water, and cook more quickly.

Cave nests have a lower swelling capacity because they are generally firmer and harder, owing to their harsh natural climate.

If the raw bird's nest disintegrates easily upon contact with water, it is a sign that the product may actually contain very little of real bird's nest.

It is also a myth that the red-coloured "blood bird's nest" is formed by swiftlets that vomit their blood to build their nests.

What happens, in fact, is that the bird's nest absorbs minerals from the cave walls, which then gives it the unique colour, Mr Ang explained.

Buyer's knowledge poor

A recent poll of 300 people by traditional Chinese medicine (TCM) retailer Eu Yan Sang found that 72 per cent consumed bird's nest.

But 66 per cent of respondents had no idea how the price or quality of bird's nest was determined.

The size and shape of bird's nest are actually the key factors in determining its price - not its nutritional value, explained Mr Ang.

In other words, you pay more for its appearance.

Those that are curved in the shape of a spoon are considered the most ideal ones.

As for whole bird's nest, it takes skill to keep the pieces intact during the cleaning process, so it tends to cost more too, he said.

The finer and more compact the bird's nest strands, the higher its price as well.

Beware of counterfeits

There are eight different grades of bird's nests, which determine their selling price.

Mr Ang said Eu Yan Sang sells only those from grade three onwards.

A tael (37.6g) of house nests at the retail outlet goes for $128 to $368, while the same amount of the less common cave nests cost between $198 and $788.

A 150g bottle of concentrated bird's nest is priced between $49.90 and $89.90.

When preparing and eating bird's nest at home, you can tell how authentic it is by observing its colour and smell.

When it is soaked in water, the strips of saliva should expand and turn transparent. But the water in which it is soaked should remain clear.

Bird's nests which have an extremely white colour may have been bleached, warned Mr Ang.

The real nests will also have a fishy tinge because of the swiftlet's saliva.

After cooking, the aroma should be like that of egg white.

Meanwhile, counterfeits will reek of additives, Mr Ang said.

You can also tell the source of a bird's nest based on how it feels in the mouth.

Cave nests tend to be crunchy and chewy, while house nests are softer, smoother and more slippery.

When buying raw bird's nest, weigh its price against the size, shape and thickness of the nest and the firmness of the threads.

Its swelling capacity, taste and smell can be judged only during preparation and eating.

Bottled bird's nest is a convenient alternative to raw bird's nest.

To tell if it is of good quality, look closely at the contents of the bottle.

The bird's nest strands should be resting at the bottom as it is denser than water, said Mr Ang.

Make it a habit to check the expiry dates of bird's nest products too.

Raw bird's nest, which has a shelf life of two years, should be stored in a cool, dry and airtight container in the main refrigerator compartment. Bottled versions can last 21/2 years from its manufacturing date.

If you are not planning to finish a whole bottle of bird's nest at one go, pour the desired amount into a cup instead of drinking straight from the bottle, as your saliva can cause it to spoil faster.

Store the remainder in the refrigerator and finish it within one week.

joanchew@sph.com.sg

This article was first published on June 19, 2014.
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