11 Time-Tested Secrets to Authentic South Indian Filter Coffee

6. Perfect the Decoction Extraction Timing

Decoction—thick, syrupy coffee concentrate—is the heart of the drink. After pouring hot water over the packed coffee, the usual drip time is 20–30 minutes for a full container. A slower drip often indicates a very fine grind or over-tamping; a very fast drip suggests a coarse grind or loose packing. Watch for color and aroma: the decoction should be deep brown with a glossy surface when it’s ready. If the top of the filter bubbles aggressively or you smell burnt notes early, you poured water that was too hot or used an overly fine grind. To test strength, take a teaspoon of decoction and mix with equal parts hot milk—this gives you a quick sense of the base before diluting for a full cup. For weaker palates, stop earlier around 18 minutes or dilute more later; for lovers of bold coffee, extend to 28–30 minutes and increase the decoction-to-milk ratio when serving.