DIMI comes from 知味, which used to be read as 'Jimi'. It comes from a phrase from an ancient text.
1、The Doctrine of the Mean「人莫不飲食也。鮮能知味也。」
There is no body who does not eat and drink.
But they are few who can distinguish flavors.
2、『飲食知味方』, a cook book from the 17th century written in hangul.