Cooling boiling water to make tea

Remember me yakking about Fancl’s green tea? Well there’s a tiny bit more to add – the recommended water temperature stated on the box (which is a new packaging, by the way) is about 80°C (or 176°F). But how do I cool down fresh boiling water in my kettle to this temperature asap?

I would usually just lift the cover to let out steam, wait 5 mins before pouring out to dissolve the tea powder. But I’ve since changed strategy because 5 mins is a bit TOO long. Now when the kettle signals that water has boiled, I’ll pour some into an empty cup first, then surely and steadily the temperature in the cup dips to the 80s almost instantly. And for just a couple more seconds, it will hover closer to 80, hence the water is ready to make my cuppa.