In my experience, you need the app if you use a valved filter (i.e. Clever Dripper) as being a little cooler, the Ember mug doesn't trigger the heating, and you have to tell the app to increase the temperature manually until it realises there's a hot drink in there.
In my experience, you need the app if you use a valved filter (i.e. Clever Dripper) as being a little cooler, the Ember mug doesn't trigger the heating, and you have to tell the app to increase the temperature manually until it realises there's a hot drink in there.