‘Khao muu daeng’.
If you compare a duck’s egg with a hen’s egg, which one comes out on top? The right answer is that each one has its strong points. Most people prefer hen eggs, however, and it is easy to find them for sale in any fresh market or supermarket where they are bought in much greater amounts than duck eggs. Cooked-to-order food shops don’t keep duck eggs at the ready for customers, who are very unlikely to ask for them.
But even though duck eggs rank low in popularity, they have a historically more important role in Thai cooking than hen eggs. Half a century ago, they were much more popular in Thailand than hen eggs, and much easier to get hold of. But for now I’d like to forget about comparative popularity and take a look at why it is that duck eggs are so integral to Thai cuisine.
One food that’s familiar to all Thais is the yellow ba-mee noodle. Every kuai tiao shop has them. In the past these noodles were known as ba-mee khai, or “egg ba-mee”. When cooks made them by kneading wheat flour with egg, they always used duck eggs because of their sticky consistency and rich, dark yellow colour.
After the flour and eggs were hand-mixed, they were kneaded until the dough was thick and firm, using a big, long bamboo tube. One end was firmly attached to a wooden post and the other was for the noodle-maker to stand on in order to knead the dough by foot. This technique of kneading vigorously by foot made the noodles firm and chewy. Then the dough was cut into strips to make the ba-mee noodles. Today all of the mixing and kneading are done mechanically, but the recipe’s requirement for duck eggs remains the same.
The viscosity of the duck egg, together with the deep yellow, almost orange colour of its yolk, make it ideal to use in many Thai dishes. One example is khai khem, or salted egg. If the yolk of a salted egg is too pale, it doesn’t look appetizing. The deep yellow colour of the salted yolk in the flaky, filled Chinese sweet called khanom pia is one of the things that attracts buyers. Khao muu daeng, or Chinese red pork in sauce over rice served with boiled egg, is enhanced if made with duck eggs, too.
Khanom khrueang thong (“golden sweets”) like thong yip, thong yawt and foy thong are made with duck eggs because of their consistency and colour. With khai phalo (eggs cooked in an aromatic brown sauce), it isn’t the colour of the eggs that makes people buy it, because that can’t be seen. It is their size.
But it is the colour that makes duck eggs a necessity in many of the recipes that use them — and the more intense the yellow, the better. A dark yellow-orange isn’t enough for demanding buyers. A shade bordering on red increases the value of duck eggs and makes them sell better than lighter-coloured ones.
Many duck farmers used to raise their birds by allowing them to roam freely in rice farmers’ fields, a system called pet lai thung in Thai. This worked out well for both farmers. In those days the paddies were plagued by a pest known as the cherry snail. These voracious animals destroyed a significant number of rice plants.
The most effective exterminators of cherry snails were big flocks of ducks. Rice farmers welcomed the itinerant ducks, which immediately set to work devouring the snails until the last one was gone.
Eggs from ducks raised in this way had good, thick, sticky whites and yolks of a deep orange, almost red colour. They were ideal for making khanom pia, khao muu daeng and salted egg, and were especially sought after during the season when khanom ba-jaang was being made. Red duck egg yolks are an essential ingredient in these boiled, bamboo leaf-wrapped, savoury festival treats. The market on Itsaraphap Road off Yaowarat have these red yolks for sale, especially for ba-jaang cooks.
These days, the pet lai thung system of duck farming is gone, as it is considered to be too risky. When a large number of ducks are permitted to roam freely and one of them becomes infected with disease, the condition can run rampant throughout the whole flock and kill them all. As a result, poultry farmers have changed their ways to raising ducks on farms as it is less arduous and diseases are easier to control.
Another reason for the change of system is the fact that cherry snails are much less numerous than they once were. However, a second natural enemy, the heron, has proliferated. During the season when farmers are preparing their fields and the paddies are not flooded yet, the fields will be full of herons finding and eating the cherry snails. When ducks are raised on farms instead of being set loose in rice fields, their egg yolks will revert to a lighter, yellow-orange colour, losing the red tint. But the market demand for red ones still places them at the top of the quality scale.
There is a chemical called carophyll red that has been used abroad to enhance the colour of egg yolks, but I have never heard of it being used in Thailand. Duck eggs from some of the big farms are red, but there is no information indicating that carophyll red is being used.
Smaller farms have found their own ways to intensify the colour of duck egg yolks. Some of them have managed to by adding calcium to the feed. Others feed them ripe papayas.
All of these facts add up to an idea of the importance of duck eggs in Thailand’s food culture. They may not be as popular with general buyers as hen eggs, but Thai cooking would be unimaginable without them.
Duck eggs. Photos: Suthon Sukphisit
‘Nam prik num kai tom’.
This source first appeared on Bangkok Post Lifestyle.