If you have the powder, just eat it.
I've used my fair share of kratom, and the easiest, fastest way is to just pour the powder in a half full bottle of orange juice, shake it up and then drink (with your nose plugged and a chaser nearby).
Also, kratom is not damaged by heat. When I have a lot of kratom (150 grams +) I make a tea with all of it, then hard boil it down to just a cup so I can take a mini-shot and get high. Even after boiling on a hard boil for three hours, the kratom is unchanged.
And, IME, normal kratom is NEVER as euphoric as the extracts. UEI, and the tincture (from certain vendors) are actually euphoric like morphine - whereas plain leaf only barely hits the spot.