Gyokuro Accident

So I've been making a lot of sencha tea recently, but one sleepy morning I pulled out the gyokuro instead, and brewed it as you would for a sencha (80 degrees celsius, 1 minute). The result was not pleasant. All the subtle sweetness and tasty flavours were obliterated completely, with only an overpowering bitterness remaining. Even the second infusion, made properly (60 degrees) was gross, and the third infusion, while drinkable, was very average. Needless to say, I'd cooked the leaves thoroughly.