I tried making coffee from soybeans. I soaked soybeans overnight. Next day, drained all the water. Use a tawa / flat pan to roast the beans on a very low heat. Took almost 90 minutes to get brown colour. We have to make sure, it is coffee brown colour, and not black or burnt. It can be also done in an oven. May take up to 4 hours, at 140 C or 300 F. I haven't tried it. Then cool and make powder. Use 1 or 2 tablespoon of this powder per one cup of water. Simmer, but not boil, gently for 5 minutes. Add soy milk. Sugar as required.
Taste like coffee but it is caffeine free. For some of us who still crave coffee taste and love aroma of coffee!