Can I boil milk unattended (and still keep the pan clean)?

Boiling the milk in the microwave is the only way to do this "unattended", and that requires a lot of trial and error to get the time just right. It also won't work with many recipes that involve stirring anything into the milk while cooking.

Out of the microwave, I use a non-stick pan, but even that requires scraping the bottom from time to time a bit to prevent solids from forming. (I use a rubber spatula for this.) I usually boil the milk on its own and and combine it with the rest of the recipe later.

Never used one myself, but what you need, I believe, is a Milk Watcher; a ceramic, glass or metal disk placed in the bottom of the pan. This will keep the milk circulating in the pan and prevent sticking and boiling over. You will be alerted that the milk is boiling by the rattling made by the disk.

To minimize the sticking and possible burning, first rinse your pan with cold water. Swirl the water around and pour out. Don't wipe the residual water from the pan. The thin layer of water that will remain is heavier in density than the milk and forms a thin film across the bottom of the pan making the casein (milk protein) less likely to stick and bond as easily with the bottom of the pan.

This doesn't make it fool-proof...if it boils and cooks too long it can still stick but if you're just scalding the milk it will minimize the amount of protein able to stick to the pan. As long as your just bringing it up to a simmer then you don't need to stir it during this process.

There is a device you can buy, known (here in the UK, at least) as a milk saver

It comes in glass, ceramic or metal.. I'm sure you could improvise your own if you can't find one. All it is, is a disk about 8cm in diameter, with a recess to collect small bubbles, and a vent on one side of the rim about 1/2 the depth of the recess, to release the accumulated vapor as one large bubble. The one in the illustration repeats the pattern on both sides, so it doesn't matter which way up it is, or if it flips.

It prevents foaming, breaks skin formation, and when the liquid is near boiling, it rattles in the pan, serving as an alarm.

Traditionally we always used a milk boiler in India growing up. The milk boiler is double boiler. you remove the whistle and fill the outer container with water and put the whistle back. Pour the milk in the milk boiler. Then close the lid and walk away. when the water reaches its boiling temperature, milk also reaches its boiling temperature. you will hear a loud whistle almost like the kettle. Then just turn the stove off and you have your perfectly boiled milk that never burns or boils over. This was a daily morning routine for us before we went to school lol.

1. You can just keep the wooden stick on the vessel and carry on with your work.
2. You can also prevent milk boiling over by applying some cooking oil on edge of the vessel. more.....

Depending on the type of stove, a heat diffuser may help. Gas stove flames tend to concentrate heat on the parts of the pot directly above the flame, which can lead to issues with burning or overheating in those spots. A heat diffuser is a metal disk which will heat evenly to make sure that the pot doesn't have hot spots.

1. enamel pot - no stirring required.
2. milk from a farmer - boils and boils

Use milk from a farmer. It might taste weird after years of drinking milk from a box, but my family buys milk from farmers and it boils so easily. First you put it in the fridge for a few hours to settle, then get the cream off the surface. If there's no cream then look for a better farmer who doesn't process the milk before selling :)

When you boil this kind of milk in a good old enamel pot you don't have to stir anything and it boils instead of running away :) I once forgot about my milk and came back a few minutes after it started boiling. Still everything was ok.

A bigger pot is absolutely possible.

I used to make paneer from 4.5 litres of milk in a 5l (actually about 5.2l) stock pot. Even the thermal expansion made it precarious. So I bought a bigger pan, 8 or 10l.

But you still have to keep an eye on it, unless you actually plan to boil it down, which is rare, and when then you'll want to reduce the heat significantly when you get near boiling point.

I can understand that you'll try to get other things done while it's coming to the boil - it's not quick. I found a thermometer helped, in that I could get a rough idea of how fast it was heating, and set a timer. For example measure how long it takes to get from fridge cold (e.g. 5°C) to about 15°C, and multiply up to get to the time it will take to reach about 80°C. Set a kitchen timer or use your phone to give you a reminder. This assumes a constant heating rate. In fact once it's well above room temperature the pan will lose heat to the room and heat more slowly, which gives you a built-in margin for error.

According to thekitchn,

Here's what's happening in that little pot:

As milk heats, the water in its structure starts evaporating from the surface. This concentrates the remaining fat and proteins into a thicker layer at the top of the pot. This layer eventually becomes so thick that water vapor rising through the milk can't break through very easily and gets trapped.

The layer is so uniform that you can't necessarily see what's boiling up right underneath, except in little bubbles around the edges. You see where this is going?!

Sure enough, enough water vapor eventually collects that it raises the thickened layer above it and breaks violently through. And, voila! The milk boils over!

There are a few ways we can prevent this from happening. One is to be sure to stir the pot of milk every few minutes to break up the top layer, allow the steam to escape, and make sure it's heating evenly. We've also heard that you can leave a long-handled spoon in the pot and the handle will provide a conduit for the steam to escape.

Leaving a long wooden spatula either in the pot or resting on the top of the pot like a divider works for me, unless it is on maximum possible heat which will almost always cause a boil-over.

The most popular tried and tested way is to Watch it like a Hawk and Never turn your back on it.

I remember in 1955 my mom had a device that looked like a big enameled upside down funnel. The funnel was placed up side down in the pan, then milk put in about half full. When start of boil the hotter milk inside the funnel would bubble out of the tip. Soon at full boil, as the milk cooled by cooler air once out of the spout. I think my mom came up with that, the funnel was not a match to anything, and I've not seen one since.

Put cream in the milk. This prevents the milk from sticking. Put a wooden spoon in the milk pot; this will break the foam and prevent boiling over. Use medium heat.

If you have one of the new electric pressure-multicookers, see if yours has a "yogurt" option, my IP Duo has it. Even if you don't intend to make yogurt, the first step includes boiling the milk, and the IP has a setting to do just that, unattended and with absolutely no spillage, and no burning on the bottom. Not even a skin forms on top. And of course, it turns itself off when it is ready. You could leave the kitchen or even go out shopping, and when you come back home, you will have hot, boiled milk.

One new option came on market. No need to keep watch on Milk, Tea etc:

http://www.abaxoenterprises.com/home.html

Just put on vessel and it remind you when it is ready.

You can boil milk unattended. Just keep it in low flame and then use a big spoon or stirrer and keep it over the vessel (like a divider). Milk will never overflow.