Ejiao has been used as a tonic for roughly 3,000 years, and its donkey-hide processing is listed as national intangible cultural heritage. Traditional blocks are simmered for what is often described as 'nine times nine, eighty-one days.' The Bencao Gangmu records it for bleeding-related conditions such as vomiting blood, nosebleeds, blood in urine, and bloody strangury. It is traditionally used to nourish blood and yin, moisten dryness, and stop bleeding.
The basic forms are quite different from one another:
Ejiao block. A traditional black, hard rectangular brick made from donkey hide after more than 40 days of processing and cutting. It usually needs a second step—grinding into powder or making it into a paste. Nutritionally it is the most intact form, but eating it straight is unpleasant. Collagen content is at least 80%. Representative brands include Dong'e Ejiao and Fu brand.
Ejiao cake. The block is melted and mixed with walnuts, black sesame, yellow wine, and other ingredients, then cooled and cut into pieces. It is ready to eat and convenient. The proportion of ejiao varies widely, roughly 10% to 40%. It tastes sweet and is often used for daily supplementation.
Ejiao powder. Made by grinding the block or by spray drying. It contains at least 40% ejiao. Mixed with water at 85°C or above, it dissolves quickly and is absorbed fast. Modern instant versions may add ingredients such as red date extract.
Ready-to-eat fresh ejiao. A powdered innovation that can be mixed directly with water or hot milk. It is marketed as 'no cooking, ready to eat' and aimed at younger consumers.
There are also composite products such as ejiao syrup and ejiao paste.
My wife had a miscarriage not long ago, so my sister bought two boxes of ejiao for her to build herself up. Last time I also ate one box—ejiao cake, the kind you open and eat, with many small packets inside. I ate a box; the taste was nothing special, but it is a tonic. This time we bought ejiao blocks. They look like chocolate but are hard as iron. One night I tried steaming a small piece in a metal bowl. Half an hour later it still had not fully melted. It looked like this stuff really needed to be simmered, and that is not easy either. So I thought about grinding it into powder. Buying a dedicated ejiao grinder did not seem worthwhile, so I started asking pharmacies whether they could process it.
Eventually I found a pharmacy that said it could grind it for free. After lunch I set out under the hot sun, but when I arrived the person was not there—something had come up and they had gone out. That was frustrating, since we had arranged it. I had to look again. Fortunately I found another pharmacy and went over right away. After a short conversation, they started grinding. The whole process took about 30 minutes. I had not expected something so hard to turn into something like soy milk powder. All told, it made only two bags. The process went smoothly, and I have to give credit to the clerk who helped.
The clerk kept saying that ejiao should not be eaten in summer—wait until winter, otherwise it can cause internal heat, since it is a strong tonic. So it will have to sit for now. If I had known, I would not have had it ground so early.