egg boiler using electric kettle

[MrAl]

Hi,

MrRB i thought you were kidding at first when i saw that "that looks like a boy" but now i see you are from the Land Down Under so i believe you KNOW your spiders pretty darn well or you would not still be here to talk about it

Have you ever went up against a Funnel Web Spider? Or do you see them very much in your area? I'd hate to run into one (or more likely a group) of them.

Dont want to get too far off topic but perhaps you guys might help here...
Also, since both of you seem to know your spiders (a very good thing to know indeed especially with the warming climate) perhaps you can help me identify a spider i've seen around from time to time. It's a bright blood red spider that in the sunlight looks translucent. I dont like spiders, but that was very unique and almost beautiful. Looked very hard for the species and more info, but could find none.

 

[()blivion]

I'm not actually all that great with spiders, just that spider is native, so I have come to know it well.

It could be a male, as it's not mating season anymore, so it becomes hard to tell. But generally speaking, you can tell a male spider from a female if the tiny arms(pedipalps) have "boxing gloves" or not. Again, not really as easy unless it's mating season.

And yeah, the down under does get the short(long) stick when it comes to dangerous animals of all kinds. I think it's like... 5-7 of the top 10 most poisonous things on the planet exist there. Like the Sydney funnel-web, as one of the most poisonous spider of course. With a setup like that, you would almost expect the place to be uninhabitable.

As for bright red translucent spider... google says something in the Ceraticelus genus probably. I would also say Florinda coccinea as they are the most red spider I could find, but you don't live in the Florida area so that's unlikely. Then again, climate change and so forth. Red color in spiders is fairly rare as I understand it.



Anyway, yeah, getting super off topic. I'm probably done now though.

 

[Mr RB]

...
Have you ever went up against a Funnel Web Spider? Or do you see them very much in your area? I'd hate to run into one (or more likely a group) of them.
...

In a previous house i killed one that was walking across the garage floor, it was pretty decrepid and only small (about 3" across). I felt bad killing it as normally I rescue indoor critters (spiders included) and release them outside up the back.

When i was young, dad and I found a large next of funnelwebs in the crook of a huge forked tree about 1 yard off the ground (talk about horror movie stuff). It got doused in gasoline and as heaps of them rushed out it got lit up. It's great being kind to animals and everything, but when there a big nest of agressive deadly spiders 60 yards from the house you have to play it safe.

Ever feed a spider water? Great for amusing kids and helping them get over their fear of spiders. With those ground spiders that get trapped in the house they dehydrate badly, you can tell from their abdomen that shrinks up. If you splash some drops of water near them they rush to a drop and start drinking it. Kids giggle; "oh look, he's having a drink!" Shows that they are just little starving critters and cuts the fear factor a lot.

 

[MrAl]

Hi MrRB,


Thanks for the interesting story about the spiders. I have heard that during a certain season they go out at night coming out of the trees and hunt for food and maybe a mate. That's the most dangerous time to be out there i guess I've also read that there is one place that is the worst but cant remember where it was now (somewhere in AU). Their venom is one of the most deadly on earth too.

Yeah some spiders are subject to dehydration as they cant take the dryness, those are the 'older' species. The more modern ones can take it better. I've never tried that though (giving them water) it sounds like it would be interesting.

I too felt bad having to 'kill' that red spider as it was not 'ugly' and scary looking like most of those we see. But i didnt actually kill it i threw it out the car window, but assumed that it would die out there on the road. Another one i felt a little bad for too, but it had made a six foot web on my car between the car and tree, so it had to go. It was pretty big too more than an inch. Another smaller one in the house made me think...i chased it around relentlessly as it kept getting away. I finally managed to get it but couldnt help but feel that it was just trying to survive and after all eat the insects like flies which we dont want around.

I think i'll start another thread in the more casual section of this forum rather than stay too far off topic in this thread. I searched more than 1000 photos and still cant find that red spider i was talking about. Maybe someone else knows what it was. I'll describe it more carefully too.

Back on topic, the air temperature some fair distance above the water is fairly cool until the water starts to boil. If the water was in a container that only had say a 1 inch diameter hole in the lid i would bet you can detect an abrupt change in temperature as the water begins to boil and the steam starts to escape. The steam is so very hot that it would heat up a sensor quite quickly where before the steam appears it would be fairly cool. That might do it too.

 

[killivolt]

Eggs don't seem to be as easy to peel as they were 20 years ago, i think the chickens are much less healthy these days and the undershell membrane is weak.

To make hardboiled eggs easier to peel I double boil, ie bring them to boil then turn the pan straight off. Wait 5 minutes, then bring it up to boil again, then likewise turn it straight off. Then allow a slow cool down in the same water. By the time the water is safe to put your fingers in and get the eggs out the shells will practically fall off.

The worst way is to bring the eggs to boil once, then take them straight out and cool them quickly in cold water! You'll lose half your egg by the time you finally break the shell off.

Roman, I wanted to find out if you have a Gas or Electric Stove. I would think there would be a difference in the process. Gas heat is instant and once boiling, the shut off is just as quick.

Electric, would build heat once to a boil there would be a remainder of heat that dissipates slowly if left on the burner once shut off.

To mimic a Gas Stove would mean pulling the kettle off the burner for 5 min and back then back on to boil and off to cool to room temp.

Or on Electric, bring to a boil and turn off the burner leaving on the coil to cool 5 min then turn burner back on to bring to boil and turn off burner to cool to room temp?

It's not rocket science but, I don't want to boil 2 dozen eggs to figure this out.

 

[Mr RB]

Hi Killivolt (and thanks for dragging away from one of my favorite topics; wildlife).

I get your point completely, but i'm not sure it makes that much difference gas or electric. For the record it was generally electric although one place I lived was gas stove, it did not seem to make any difference that I noticed.

When boiling eggs I use a deep saucepan with real thick base and walls, and cover the eggs with a LOT of water, almost filling the pan. If there is limited water "headroom" over the eggs they bounce on the pan bottom and crack the shells. With a deep pan and lots of water they don't slam on the pan bottom and you rarely break a shell.

With a thick walled pan and lots of water, the time for the water to go from room temp to boil is pretty much the same (regardless of gas or electric I think). Likewise when the heat is turned off the cooldown of that mass of water is quite slow.

Before anyone thinks I'm trying to be some sort of self-appointed egg expert I'm not, but I was quite serious in bodybuilding for a lot of years and it was pretty normal for me to be boiling 6-10 eggs a day (as you mainly eat the egg whites, so you need lots of eggs). Also I don't like cracked eggs with water inside or eggs that are a pain to peel and rips your egg to pieces.

My recipe, which was as much for lazy convenience as to get a good result;
1. Eggs in deep pan, almost filled with water (3" or more of water over the top of eggs)
2. Turn it on full until you hear it boil (no effort)
3. Turn it off. Wait maybe 5 mins (sometimes forget and wait 1/2 hour, doesn't seem to matter)
4. Turn it on full until you hear it boil (no effort)
5. Let it cool down at least until luke warm, (or if you forget might be an hour)
6. Result; perfect hard boiled eggs, good firm whites, excellent shell separation

As for a gadget to do this, I would use an immersed temp sensor and just bring the temp up to 99'C, turn off the power, wait X period, then turn it on again until 99'C again. I have no idea how short you can make the X period between boils but it's probably equivalent to a few minutes constantly boiling.

For the shell separation I think it's to do with the eggs being very well boiled and maybe the thermal expansion/contraction of a couple of cycles, but they definitely peel a lot better than a single boil.

(everything here is for cooking hard boiled eggs)

 

[alec_t]

Are you aiming for soft-boiled eggs or hard-boiled? The timing would be critical for soft-boiled.

 

[MrAl]

Hi,


Yes good point alec. I would think it should be based on weight. A heavier egg needs more time than a lighter weight egg. More than one egg at a time would probably change things a little too. Might require some experimentation, but that could be done over time with each use, logging the results of each time setting and egg weights and count.
And what to do about eggs of varying sizes. Maybe have to do eggs of the same size only in one cooking cycle.

 

[elfcurry]

The egg project so far:

Are you aiming for soft-boiled eggs or hard-boiled? The timing would be critical for soft-boiled.

For hard boiled eggs, the cooking technique seems pretty easy with much more relaxed timing constraints: boil for long enough, peel, eat. To make peeling easy I always cool them quickly in cold water then preferably peel straight away unless being kept for later use.

No, when starting this discussion I meant soft boiled eggs as I like them for breakfast eaten with a spoon. I want a soft runny golden yolk but a firm white. I want a repeatable process for something with critical timing which I often get a bit wrong when cooking in a saucepan on the gas hob.

Because I like the idea of a simple h/w and s/w project involving creating something useful from something else which has failed in its original purpose and I have an electric kettle (see typical electric kettle ) with a broken automatic cut-off. I also have several related projects in mind which require measuring temperature and intelligently controlling a mains heater, so this seemed a suitable project. I mentioned before that I'd done something similar with heating a seed tray.

So, my project is for soft boiled eggs in a 240V AC mains electric kettle using a microcontroller to somehow sense temperature or detect whether it's boiling and keep track of the time and ideally remove the eggs from the water as soon as deemed cooked to avoid further unwanted cooking. Cooking time will be probably 3-4 minutes and if it's a known time it can be adjusted to perfect the method (including variations of weight as you say Mr Al). The μC will need to control the mains and the simplest method as established above would be a solid state relay. One of the aims was to avoid power wastage so I don't want furious boiling just to make the project easy. Gentle boiling for a timed period the aim.

The temperature sensor of choice for me would be a Dallas DS18B20 which is accurate enough for normal use and employs a digital signalling technique. I've used them before and I still have some of them, so I'm not so keen on using a different sensor without a good reason. I'd originally ruled them out thinking that boiling point would be too hot for them but someone above kindly pointed out that they're ok up to 125°C so they're probably back on the menu for measuring temperature.

But my other worry was whether maintaining the water at boiling point would achievable without wasting power, just by measuring the temperature. Crudely, yes it'd work but not well enough probably. To keep a litre of water near boiling point, it would need to wait until it goes off the boil and notice the reduced temperature to know that the heat must be re-applied. That's a slow control loop IMO when the whole process is only ~3mins. That's why I was considering using the sound of boiling (cavitation as someone above said) which I still suspect is a better indicator of how vigorously it's boiling. No-one seemed keen on this and I don't know how to use sound in this way. So back to using temperature as the control variable.

Someone said that keeping it just under BP would be easier and may make no practical difference to cooking the eggs, so I'll try that to start with.

Sorry this is a bit long. I rather lost track of who said what due to the tangents on hard boiled eggs and spiders.

Thanks all. More comments on the project or variations are still very welcome.

 

[killivolt]

I don't want furious boiling just to make the project easy. Gentle boiling for a timed period the aim.

You might want that rapid boil, based on the type of kettle I seen it wouldn't be practical. It looks like a tea pot to me. If it had a stopper would be perfect for my suggestion.

To keep a litre of water near boiling point, it would need to wait until it goes off the boil and notice the reduced temperature to know that the heat must be re-applied. That's a slow control loop IMO when the whole process is only ~3mins.

So, use dual sensing, one is Temp and the other physical. I was thinking that putting a stopper for steam release and a optical sensor on the lid. Much that same as a (Old style Tea Kettle)

That's why I was considering using the sound of boiling (cavitation as someone above said) which I still suspect is a better indicator of how vigorously it's boiling. No-one seemed keen on this and I don't know how to use sound in this way. So back to using temperature as the control variable.

Yes and no. If you have dual you would know approximate temp is achieved and the stopper would activate the Optical Sensor verifying it. Run this in a Pic Program to count down time x = 3min. If you want hard boil have a switch activate a second program for hard boiled eggs, the first program being soft.

I really think you have a fun little project, I'll be watching to see the out come.

Good Luck

 

[MrAl]

Hi again elfcurry,

So you think spiders like eggs too?

If you want to get a little more sophisticated you might add a weight scale to the project. You could weigh the pot+water before you add the eggs, then weigh again after adding the eggs. That would tell the total weight. It would be best to do eggs of the same size too because the smaller ones would have to be removed before the larger ones, and sizes do very quite a bit. But with the weighing the uC could then do all the work of calculating the required cooking time as well as the overall electrical control. That would be pretty cool i think.

 

[alec_t]

Post deleted

 

[alec_t]

Someone said that keeping it just under BP would be easier and may make no practical difference to cooking the eggs, so I'll try that to start with.

That would be my first step.
A quick google found this result from measurements made with eggs heated in a constant-temperature water-bath:-

64 °C Thick white is setting. Thin white is also setting but to a lesser degree. Gel like. Yolk also began to solidify.
Yolk expanded.
68 °C The whites have set. The yolk is relatively solid. Yolk holds its shape. Overall, the egg is a little bit more than soft boiled.
75 °C Yolk is still getting more solid. Yolk can now break apart into separate solid pieces.

So it isn't necessary to boil the water and a simple temp sensor should suffice for control.

 

[MrAl]

Hi again,

I forgot to mention that hard boiled eggs and scrambled eggs are considered safer for human consumption. That's because of the temperature required to produce an egg where are the parts are firm not liquid. I dont know what the risk is however, but there is some small risk unless cooked until firm.

 

[killivolt]

That would be my first step.
A quick google found this result from measurements made with eggs heated in a constant-temperature water-bath:-



So it isn't necessary to boil the water and a simple temp sensor should suffice for control.

Was this taken at sea level or was it taken at another elevation?

 

[killivolt]

Hi again,

I forgot to mention that hard boiled eggs and scrambled eggs are considered safer for human consumption. That's because of the temperature required to produce an egg where are the parts are firm not liquid. I dont know what the risk is however, but there is some small risk unless cooked until firm.

Cooking reduces the number of bacteria present in an egg; however, a lightly cooked egg with a runny egg white or yolk still poses a greater risk than a thoroughly cooked egg. Lightly cooked egg whites and yolks have both caused outbreaks of SE infections. Cooked eggs should be consumed promptly and not be held in the temperature range of 40 to 140°F for more than 2 hours.

It does increase the possibility.

 

[alec_t]

Was this taken at sea level or was it taken at another elevation?

I have no idea. Some adjustment would be necessary for barometric pressure. Yet another input to the micro . Here's the link:
https://www.google.co.uk/url?sa=t&r...xOedJEXIxgfo89wfGFR_R8w&bvm=bv.42080656,d.d2k

 

[killivolt]

I have no idea. Some adjustment would be necessary for barometric pressure. Yet another input to the micro . Here's the link:
https://www.google.co.uk/url?sa=t&r...xOedJEXIxgfo89wfGFR_R8w&bvm=bv.42080656,d.d2k

It's typical for the measurement to be at sea level.

 

[elfcurry]

You might want that rapid boil, based on the type of kettle I seen it wouldn't be practical. It looks like a tea pot to me. If it had a stopper would be perfect for my suggestion.

Why rapid boil? My intention was to control the heating element by switching the current. It must be possible to have gentle, controlled boiling, but maybe not easy or not worth the bother if there's an easier way to cook eggs.

I showed you a tea pot? No - Here be teapots! I make tea by boiling water in a kettle and pouring onto tea in the pot. It's a dying art!

I'm very reluctant to seal it. I don't want a pressure cooker which is what it would become. Properly sealed it would raise the boiling point and reduce the cooking time. Not properly sealed I think would be no different to unsealed. More seriously it would be dangerous to try to seal a plastic vessel containing boiling water! Even so, the design shape always includes a pouring lip, so it wouldn't be easy to do.

Actually, going back to making tea, you can get a machine to make early morning tea for you by your bed. Teasmade A timer starts the heating in a small sealed electric kettle and when it boils, the pressure forces it out of a spout into a teapot. The kettle sits on a microswitch and the weight reduction turns off the power to the kettle. I have one my sister wasn't using. Now that's a small sealed kettle - maybe it could be used for eggs. The problem is that I'd still need to control it so the water is kept hot for a predetermined time. And on safety grounds if the control system lets it boil, you get boiling water gushing about. Not good.

So, use dual sensing, one is Temp and the other physical. I was thinking that putting a stopper for steam release and a optical sensor on the lid. Much that same as a (Old style Tea Kettle)

What type of optical sensor? Does it 'see' the steam escaping?

Yes and no. If you have dual you would know approximate temp is achieved and the stopper would activate the Optical Sensor verifying it. Run this in a Pic Program to count down time x = 3min. If you want hard boil have a switch activate a second program for hard boiled eggs, the first program being soft.

I think it might be interesting to have temperature and something else. Humidity? I did get a sensor not long ago but it doesn't claim to be at all accurate and I haven't tried using it yet. I thought of using that to detect a drop in the moisture content of air rising from a bread toaster so I know when it's done.

I really think you have a fun little project, I'll be watching to see the out come.


Good Luck

Thanks. Yes, I think so. But as I said in the OP I'm a bit slow in getting on with things.

 

[killivolt]

Why rapid boil? My intention was to control the heating element by switching the current. It must be possible to have gentle, controlled boiling, but maybe not easy or not worth the bother if there's an easier way to cook eggs.

A rapid boil like most Tea Pots whistle when it reaches a boil. **broken link removed**

The back of the flapper put an Infrared Emitter/Receiver that would trip when it went up at boil.

showed you a tea pot? No - Here be teapots! I make tea by boiling water in a kettle and pouring onto tea in the pot. It's a dying art!

I didn't realize that was what you were referring. I thought it was just a pot.

very reluctant to seal it.

Me either, just need a flapper to flip up and down between the Emitter Detector.

type of optical sensor? Does it 'see' the steam escaping?

Nope, just like walking into an elevator it detects the light being blocked between detector/emitter

, I think so. But as I said in the OP I'm a bit slow in getting on with things.

Been there, do that all the time. I'll be a 100yrs old before I get them completed.

Time and Money.

I liked alec_t's might work really well.