Nani's Rules for a Perfect Aam ka Achar

1. Only firm, raw Totapuri or Ramkela mangoes. If it yields to a thumb press, it goes in the chutney pot, not the pickle barni.

2. Sun-dry the cut mango for a full day. Moisture is the enemy of a long-lived pickle.

3. Roast each spice separately. Fenugreek burns faster than fennel; a single burnt spice ruins the whole batch.

4. Cold-pressed mustard oil, always — heated once until it just smokes, then cooled completely.

5. A ceramic barni, never plastic. The pickle needs to breathe.

6. Twenty days of patience. Shake the barni every morning, keep it in the sun, and don't open it early. Nani could tell by the smell alone when it was ready.