It seemed that in the past you could drink a Flaming Humbaba, and grind up to 750 chunks of ore with no energy expenditure. You could begin grinding even if you did not have enough energy to complete the action provided the Flaming Grinder Buff was on. And even though the buff expired while you were grinding, the entire action was "free".
Tonight it seems that the buff has been seriously nerfed. Is it now only working during the period of time that the buff is actually running (30 sec)? If so that makes a big difference in how useful this cocktail is for grinding.