First published 4 June 2020
Do you know about the different coloured eggs you find in Thai markets? Pink and white are the most usual.
The pink eggs (kai yiew ma) are based on a traditional Chinese method of curing eggs described by Wikipedia as follows:
"Century egg or pidan also known as preserved egg, hundred-year egg, thousand-year egg, thousand-year-old egg, and millennium egg, is a Chinese preserved food product and delicacy made by preserving duck, chicken or quail eggs in a mixture of clay, ash, salt, quicklime, and rice hulls for several weeks to several months, depending on the method of processing.
Through the process, the yolk becomes a dark green to grey colour, with a creamy consistency and strong flavour due to the hydrogen sulphide and ammonia present, while the white becomes a dark brown, translucent jelly with a salty flavour. The transforming agent in the century egg is an alkaline salt, which gradually raises the pH of the egg to around 9–12, during the curing process. This chemical process breaks down some complex, flavourless proteins and fats, which produces a variety of smaller flavourful compounds."
Myths: the pink is man-made and has nothing to do with pink chickens! The colours are only to differentiate them from normal eggs. These can also be called horse pee eggs and some people suggest that the traditional method was to soak the eggs in that useful farmyard output! However, as the scientists point out the required chemical reaction can not be achieved using horse pee (thank goodness) and it probably relates more to the initial smell when cracking the shell, which is reassuring
The pure white eggs (kai kaem) are made by soaking the eggs in a brine solution before boiling and needless to say they then become a very salty egg! Both types are used in specialised recipes you can find on the net.