spokewrench
Well-Known Member
- Region
- USA
1965: God said to Abraham, "Kill me a son."
Remember the siren? I just bought two! They're marketed as freezer alarms. If an electrical receptacle goes dead, a 9V battery sounds the siren.
Brewing coffee one cup at a time was a dead giveaway that I'm a snob, so I switched to instant years ago. I bought a thousand-watt digital tea kettle. It's designed to heat water to boiling, then register its temperature as it cools. Water doesn't have to boil for instant coffee, but there was no meaningful temperature reading until it boiled. It would take 40 Wh to heat water for 8oz of coffee. That's almost what my refrigerator uses per hour. If I wanted several cups during a power failure, that could mean a lot of battery drain.
An immersion heater can heat a cup of water to 145 F for 15 Wh. That's 3 minutes with a 300 W unit. They tell you to watch an immersion heater while it's in use, but that's not foolproof. I use a digital countdown switch such as I use to charge my bike battery and my smart phone.
Hot water in an open cup can cool fast through radiation, evaporation, and conduction. That's where the freezer alarm comes in. The countdown switch has two outlets. One is for the alarm, stuck to a board behind the counter. I put 8oz of water in a ceramic mug, put the heater in, switch on the alarm so I know it works, and shut it off by 3 presses on the minute switch on the timer. That siren was so loud that I taped over the "speaker." It's still loud. I know immediately when the water is ready. I switch off the alarm, stow the heater in a ceramic mug at the back of the counter, and make hot coffee.
I wanted to be able to make coffee efficiently in a power failure, but look at the counter space I've saved, and now I know as soon as my water is hot.
Remember the siren? I just bought two! They're marketed as freezer alarms. If an electrical receptacle goes dead, a 9V battery sounds the siren.
Brewing coffee one cup at a time was a dead giveaway that I'm a snob, so I switched to instant years ago. I bought a thousand-watt digital tea kettle. It's designed to heat water to boiling, then register its temperature as it cools. Water doesn't have to boil for instant coffee, but there was no meaningful temperature reading until it boiled. It would take 40 Wh to heat water for 8oz of coffee. That's almost what my refrigerator uses per hour. If I wanted several cups during a power failure, that could mean a lot of battery drain.
An immersion heater can heat a cup of water to 145 F for 15 Wh. That's 3 minutes with a 300 W unit. They tell you to watch an immersion heater while it's in use, but that's not foolproof. I use a digital countdown switch such as I use to charge my bike battery and my smart phone.
Hot water in an open cup can cool fast through radiation, evaporation, and conduction. That's where the freezer alarm comes in. The countdown switch has two outlets. One is for the alarm, stuck to a board behind the counter. I put 8oz of water in a ceramic mug, put the heater in, switch on the alarm so I know it works, and shut it off by 3 presses on the minute switch on the timer. That siren was so loud that I taped over the "speaker." It's still loud. I know immediately when the water is ready. I switch off the alarm, stow the heater in a ceramic mug at the back of the counter, and make hot coffee.
I wanted to be able to make coffee efficiently in a power failure, but look at the counter space I've saved, and now I know as soon as my water is hot.
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