Will A Kettle Filled With Alcohol Boil Dry?

The average home kettle is set up to switch off automatically when water reaches its boiling point. But would a kettle filled with alcohol, which has a significantly lower boiling point, actually turn off? [Steve Mould] set out to find out.

The prediction was that a kettle full of 40% strength vodka would boil dry, as the vodka would evaporate before it actually got to a hot enough temperature to cause the kettle’s cutout mechanism to kick in. The experiment was done outside to minimise the dangers from the ethanol vapor. As it turns out, the vapor from the boiling vodka is about 80% ethanol and just 20% water, so eventually the mixture left in the kettle is mostly water and it boils hot enough to trigger the cutout mechanism.

However, the experiment doesn’t end there. Trying again with 99% ethanol, when the fluid started boiling, the kettle switched off even more quickly. So what’s going on?

The kettle in question uses a bimetallic strip, which trips the switch off in the base of the kettle when it gets too hot. There’s also a tube inside the kettle that carries vapor from the internal cavity and lets it pass over the bimetallic strip. When the liquid inside the kettle boils, it forces hot vapor through the tube, out of the kettle and over the bimetallic strip.

This strip triggers at a temperature significantly lower than the boiling point of water; indeed, as long as the liquid in the kettle is fairly hot and is boiling enough to force vapor out the tube, the kettle will switch off. [Steve] points out that it’s a good mechanism, as this mechanism allows the kettle to respond to boiling itself, rather than the arbitrary 100 C point which water technically only boils at when one is at sea level.

It’s an interesting look at a safety system baked into something many of us use every day without even thinking. It’s not the first time we’ve seen [Steve] dive deep into the world of tea-making apparatus, either. Video after the break.

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A Little IoT For Your PID Tea Kettle

For some folks, tea is a simple pleasure – boil water, steep tea, enjoy. There are those for whom tea is a sacred ritual, though, and the precise temperature control they demand requires only the finest in water heating technology. And then there are those who take things even further by making a PID-controlled electric tea kettle an IoT device with Amazon Echo integration.

Nothing worth doing isn’t worth overdoing, and [luma] scores points for that. Extra points too for prototyping an early iteration of his design on a RadioShack Electronics Learning Lab – the one with a manual written by Forrest Mims. [luma] started out using an Arduino with a Zigbee shield but realized the resulting circuit would have to live in an external enclosure. Switching to an ESP8266, the whole package – including optoisolators, relays, and a small wall-wart – is small enough to fit inside the kettle’s base. The end result is an MQTT device that publishes its status to his SmartThings home automation system, and now responds when he tells Alexa it’s time for tea.

Projects that hack the means of caffeine are no strangers to Hackaday, whether your preferred vector is tea, coffee, or even straight up.

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Hacklet 121 – Tea Hacks

Last week on the Hacklet I covered coffee hacks. Not everyone likes coffee though. A good portion of the world’s population enjoys a nice cup of tea. Different cultures are rather particular with how they prepare their drink of choice. Americans tend to use teabags, while British, Chinese (and much of the rest of the globe) generally prefer loose tea leaves. Everyone has their own particular style, which has led to quite a few tea hacks. This week’s Hacklet is all about some of the best tea projects on Hackaday.io!

teapiWe start with [James P.] and Tea Pi. Tea Pi is designed to emulate commercial tea makers costing hundreds of dollars. The heart of the operation is a Raspberry Pi, making this one of the first Linux powered tea makers we’ve ever heard of. An Adafruit PowerSwitch Tail allows the Pi to control a standard tea kettle. The Pi monitors water temperature with a DS18B20 temperature sensor. A simple servo drops a tea basket into the water for brewing. When the time is up, the servo pulls the basket up and the tea is ready to serve. [James P] planned to add voice control to his tea creation. I’m betting that would be pretty easy with Amazon’s voice services for the Raspberry Pi.

eyeoteaNext up is [Tom] with Eye-O-Tea. With this project, even your cup of tea can join the Internet of Things. Eye-O-Tea essentially is a web connected coaster with temperature monitoring built right in. Temperature is measured with a Melexis MLX90615 IR thermometer. An Arduino Pro Mini reads the temperature and passes it on to an ESP8266 WiFi module. The entire device is powered by a LiPo battery, and neatly housed in a gutted cup warmer. On the cloud side, [Tom] used ThinkSpeak and freeboard.io to make an interface he can access with his cell phone. If his tea is too hot, Eye-O-Tea will let him know. It will also send him an SMS if he’s forgotten his cup and it’s going cold.

chaiNext we have [Adrian] and ChaiBot. Chaibot was created by [Adrian’s] son [Oliver] to combat a common problem. Both father and son would pour cups of tea, then get involved in a project. By the time they came back, they had ink. ChaiBot steeps the tea for a set amount of time, stirring every minute. The mechanics of the project came from an old CD-ROM drive. A PIC16F887 runs the show, ensuring the steep time is accurate, and activating the motor drive. When the tea is done, an ESP8266 sends a push notification to the user’s phone. The project is housed in a wooden case that fits perfectly on the kitchen counter.

inductFinally, we have [Siggi] with Camper Induction Cooker, a 2016 Hackaday Prize entry. [Siggi] needed hot liquids on the go, but he didn’t want to fool around with heating elements. An induction heater was the way to go. A Cypress PSOC micro controls the system. Metal travel style mugs can be used without modification. For ceramic or plastic mugs, a metal washer (hopefully coated with something food safe) acts as an immersion heater. The project is definitely a bit unwieldy at the moment, but I could see [Siggi’s] idea being incorporated into automotive cup holders. [Siggi] put his project on hold back in June. I hope seeing his work on the front page will get development moving again.

If you want to see more tea projects, check out our new tea projects list. See a project I might have missed? Don’t be shy, just drop me a message on Hackaday.io. That’s it for this week’s Hacklet, As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

Fetching Etchings For Stainless Steel

What do you do when you have a 10-gallon brew kettle (or any other stainless steel or aluminium thing) with no volume markings (or Hack a Day logos)? If you’re [Itsgus], you use science to etch some markings with a few household items and a 9V and you call it a day.

[Itsgus] used 1/4c vinegar and 1/4tsp of salt to form an electro-etchant and applied it with a Q-tip connected to the negative terminal of a 9V. He used tape to connect a wire between the positive terminal and the kettle. The vinegar dissolves the salt, creating negatively charged ions. Connected correctly to a 9V, the process removes metal where the current flows. If you were to connect it in reverse,  you would add a small amount of metal.

The process only takes a few seconds. When the etchant starts to sizzle and bubble, Bob’s your uncle. Even though the stainless steel’s natural coat re-oxidizes over the etches, you should probably wash that thing before you brew. If you prefer adding metal to removing it, try electroplating copper on the cheap.

Copper Kettle Just For The Hipster Coffee Scene

04-copper-kettle

Handmade coffee is a feature we need to write. But for now we present this copper kettle which is designed to pour out the boiling water very slowly in order to achieve the perfect cup of slow-drip java.

[CHS] made the kettle for his friend [Nate]. The entire process starts off with an arc of flat copper sheet which makes a slightly conical cylinder when curved until the two ends meet. Getting a water tight seal on this seam is imperative and it took four or five tries to reach perfection.

To get the kettle in shape [CHS] improvised a mandrel out of a thin slice of railroad track. After polishing it smooth it goes on the inside of the copper and gives him something to hammer against. We think this step is magic… It’s kind of like the old sculpting adage that you remove everything that isn’t what you’re trying to end up with. The beauty of the piece really pops out as the final curves are hammered into the work.

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Double-kettle Boiling Rig For And Easier Brew Day

[Dave] built a controller that lets him boil two kettles at once when brewing beer. The setup uses electric heating elements in each of the kettles. We prefer to use gas as it’s a bit easier to control temperature. But an electric system like this can be used inside during the winter months while propane is relegated to the outdoors. The other thing that immediately comes to mind is partial mash recipes that require steeping in one kettle, then sparging (rinsing off the grains) with water of a different temperature. That kind of thing is a snap since the two are controlled individually by the trimpots on the front of the control box.

Inside you’ll find two 220V solid state relays. The box itself plugs into the 220V outlet in his basement which is normally occupied by his clothes dryer cord. So as not to blow a fuse, the MSP430 chip driving the relays switches back and forth between them rather than turning both on at once. The system uses entirely manual control, but it should be an easy modification to add a thermocouple and PID algorithms if so desired.

After the break [Dave] shows off the system in a video clip.

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Pulse Jet Tea Kettle

[Colin Furze] is just showing off in this picture. His pulse jet tea kettle is built well enough to get by without help from a blow torch, but who can blame his showmanship? In fact, once it’s running there’s no flame to be seen. That’s because the combustion happens at an earlier stage of that pipe, heating a segment that is submerged in water so that you may have your tea in no time.

Once this thing is tuned up it roars like a robotic lion. [Colin] yells his commentary at the camera, but it is picked up as nothing more than a blip of distortion. Pressurized propane and air both feed into the jet. they’re regulated by the two knobs on the base of the unit (that enclosure is actually just a pie tin). There is also a 9V battery-powered igniter built into the base. You can see how the unit was built in the video after the break.

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