(1) Size and volume

The most popular shapes are the boat or spoon shape. If swallows build their nests on the corner of two walls, the shape of nest will become triangular. There is no effect on the nutrition value. Wider bird´s nests cups have higher quality. Natural bird nests cups are genuine bird nests.

(2) Color and purity

The highest quality of bird nests are naturally colored without any sand, soil, or moss. White bird nests are in color of slight "ivory". Yellow bird´s nests are in color of slight "beige" or "golden". Red (blood) bird nests are in red. All the bird nests will rehydrate and turn into lighter color after soaking in water, and the thread of bird nests will become transparent. The water after soaking bird nests normally remains clear. However, the water after soaking red (blood) bird nests will become a little bit yellow. If the bird nest is extremely white, it may have been bleached, and will greatly reduce the nutrition content and harm the health.

(3) Density and volume after soaking

If threads are thinner and closer, and size is large and thicker, bird nest cups will expand more after soaking. Bird nest of different grade have different expansion ratios. The weight after soaking is several times of that before soaking. The "degree of expansion" refers to the degree of water absorption. A larger degree means greater expansion and volume.

(4) Taste and humidity

The bird nest should have the distinct smell of bird’s saliva and blood, as well as a slight aroma of egg whites after being cooked. If bird nests are too sticky or soft, the moisture content is high, storage is difficult and mold grows easily, so it is best to choose ones that are dry.

(5) Price and trustworthiness

Price of bird nests is judged by their taste, size, thickness, dryness and density. The best choice is to purchase from trustworthy shops with quality assurance.

Genuine VS Fake, Good quality VS Poor quality

Only natural bird nests are genuine bird nests. There are illegal acts of painting the placing under spotlight. Genuine bird nests are translucent. "Gutta-percha" or "pig's skin" is used as counterfeit goods and will give sour taste and will not appear as threads; those made of pig's skin will produce oil and milky appearance in water when soaked.

To differentiate between good grades and bad grades, in general bird nests of better quality and higher grades are of higher nutritional value and greater expansion degree. The outlook is also neater. Those of lower quality are of lower nutritional value and less expansion degree. Outlook is also inferior.