Not a fond of milk + it's unhealthy (even dangerous if you have some allergy like me or asthma or sore throat/cold) so I exchanged it on smetana (not fat), kefir (YUM! Fermented lactosa-free milk which tastes much better), cheese, quark (I make a "yogurt" out of quark with bananas, cocoa powder, strawberries, ribes, apricots, raspberries etc).
After you boil grechka a little amount of hot water should still be there. And grechka grains should break up - that means it became really soft and ready. There's fat in milk which made grechka heavier to digest. I refused from white sugar, just take glucose & fructose naturally via ordinary food all of us eat daily.