The short answer
Chakki atta is whole wheat flour ground between stones (a chakki) instead of steel rollers. Grinding slowly keeps the bran and germ in the flour, giving rotis more flavour and fibre, and a slightly coarse texture that holds water well for soft rotis.
Chakki vs roller-milled
| Chakki atta | Roller-milled atta | |
|---|---|---|
| Grinding | Between stones, slower | Steel rollers, faster |
| Bran and germ | Kept in | Often partly removed |
| Taste | Nutty, wheaty | Milder |
| Roti | Soft, wholesome | Can be paler, drier |