When buying preserved eggs, what is the difference between yellow and black eggs? Which one is better?

In terms of production technology, the difference between yellow-centred preserved eggs and black-centred preserved eggs lies in the content of edible soda ash and external lime. The former has a lower content, while the latter has a higher content, so there are two differences when making them. kind of result. One has a yellow heart or a red heart, and the other has a black heart, but there is nothing wrong with both of them and you can eat them with confidence. At the same time, yellow preserved eggs are mostly made of eggs, with fewer egg whites and egg yolk ingredients, and are left for a short time, which is called "changing eggs". Black preserved eggs are mostly made from duck eggs. The egg white and egg yolk ingredients are heavier and need to be left for a long time. Pine branches and cypress branches are added to the ingredients, which is called "preserved eggs".