I made stock last Sunday, which I intended to use as the base for homemade tonkotsu (pork broth) ramen. Accordingly, I used both chicken and pork (roughly equal amounts of chicken backs and pork hocks). I also added several cloves of garlic, a large leek, celery, carrots, and small knob of ginger.
I boiled the meat/bones briefly before straining and starting over with cold water (for clarity of finished stock), added the other ingredients, and brought to a boil. I then reduced to a simmer and skimmed the very small amount of scum from the surface. The stock simmered for about 8 hours before I strained it through a cloth.
The resulting stock is perfectly clear, with an excellent, thick mouthfeel and gelled nicely in the refrigerator. However, the stock also has very little flavor-- even copious amounts of salt don't help much. Since my stock is by all other measures a success, I'm puzzled as to why it's so flavorless.
Where did I go wrong?