On a recent ride I found a discrete spot with a nice solid concrete base and used my stove to brew up a tasty aeropress coffee with fantastic views over open moorland. Overall the stove + pot + gas were heavier than an (empty) flask, but I'm getting ready for a tour so carrying the extra few grams wasn't a big issue even on a day with 1750m of climbing.
Would like to think that the coffee tasted even better due to the water being freshly boiled!