Zojs are well insulated hot water dispensers, a keurig is a pod-type coffee machine, so I assume it’s just an un-insulated plastic reservoir (though hopefully it doesn’t keep the entire reservoir hot, only the water for the “next dose” for people who can’t cope with waiting 30 seconds for the machine to heat up)

I really wish keurig would just have a big capacitor inside to insta-heat the water beyond what’s possible from mains in real-time. But I guess there’s too much risk of shocky shock.

> I really wish keurig would just have a big capacitor inside to insta-heat the water beyond what’s possible from mains in real-time. But I guess there’s too much risk of shocky shock.

I'm not sure that's an option unless you have a capacitor larger than the device. Heating water takes a lot of energy: let's say we're talking 200mL water (0.2kg), ambient temperature is 20C, water has a specific heat of 4.2kg/kg.C, so that's 67200J.

A Maxwell K2 3000f 3.0v would store a hair under 13500J, which isn't even remotely close, and these things are huge (https://youtu.be/y8tQesYvCig?t=10), heavy (>500g), and each would be a significant fraction of the keurig's existing price.

If you need to strap 5 capacitors to the keurig, danger aside, you've added 2.5kg to the thing, you've strapped a pack twice the size of the brewer, and you've at least doubled and probably close to tripled its price.