[maxbond]

The good news is that boiling water is not functionally necessary since the extraction was done up front. I drink it cold or with warm water. Boiling is hotter than I want to drink anyway.

If there's significant scale at the bottom it's possible it's making your kettle materially less efficient. If you put in like a cup of vinegar and a cup of water (you could probably dilute it more than that), heat it up and swish it around (it doesn't need to be boiling), it should all come off.

[chihuahua]

I found that 160F to 180F is enough for instant coffee, depending on personal taste and what you feel like at that moment. I have an electric kettle that has a several buttons for different temperatures, and heating only to 180F saves time over heating to boiling, plus I can drink it right away.

[mbirth]

Yep, all the instant coffee jars I’ve seen have a note to use hot but NOT boiling water. And I’ve noticed that using too hot water can even spoil the taste a bit.

I usually turn off the kettle when the noise starts noticeably changing. This usually is something between 70-80℃.

[kccqzy]

Indeed. I have a Nespresso machine for when I need coffee quickly. As soon as I press the button, hot water flows in a trickle. It’s certainly not boiling but it’s an ideal temperature as a hot drink.