Not every shop with a stone in the window is milling your flour. Here is how to tell, quickly, without being rude about it.
1. "When was this ground?"
The single best question. A working chakki knows, to the day. If the answer is a shrug, a vague "fresh only", or a change of subject, you are buying pre-ground flour that arrived in a sack.
2. "Can I bring my own grain?"
Most genuine chakkis will grind grain you bring, for a fee per kilo. It is their original business. A shop that refuses outright is usually not set up to mill on demand at all.
3. Look at the stones, not the counter
Are they dusted with flour and clearly in use, or clean and ornamental? A mill that runs leaves evidence everywhere. A showroom stone is spotless.
4. "Do you clean between grains?"
If you want gluten-free jowar or bajra, this matters enormously. A mill that grinds wheat all morning and then your millet without dressing the stones is handing you traces of wheat. Ask. Watch the face, not just the answer.
5. Smell it
Fresh whole wheat flour smells faintly sweet and nutty. Older flour smells of very little, then eventually of old nuts or crayon. Your nose is a better instrument than you think, and it needs no equipment.
The one that catches everyone
A lot of shops now sell branded pre-packed flour and run a grinder for show. Both things are true at once, and the sign outside says chakki. If you want the milled-today version, you have to ask for it specifically — and then ask question one.