This story take place after a few thousand the eternal lord become the divine chef, because he was getting bored of becoming a chef he searched a new way to past time and somehow he choose to become an alchemist and he was determined to learn it and make it one of his passtime activities.
But he just found that making a pill need to use a huge amount of herb and other ingredient and some of them can be used to improve the efficacies and taste of a food and maybe because he was the divine chef he feel that it was to wasteful to use such ingredient and make into some pill that only have the effect but taste horrible, so he tried to make a pill without such herb or ingredient and after a few thousand year he did it but it was limited and it consume so much time from gathering the ingredient and making it.
This novel's true home is a different platform. Support the author by finding it there.
As a side note the eternal lord have a habit of shortening the time of everything he do and because of this all of his technique have a similar aspect in which that was instant and also because of this habit he forget the point of his reason to learn alchemy in which that was to use ot as a passtime activity and if he create a technique that can make a pill instantly meant that he can't use it as a passtime activity at all, and maybe because he forget his reason he go into a secluded meditation in order to find a way to make a pill instantly.
In the future there would be a legendary technique among alchemist this technique can take the essence form heaven and earth directly and refine it into a pill without a furnace, the so called pill from nothingness.