What's the difference between boiling food and steaming it? The answer is, quite a lot.
Food cooked in steam tends to absorb less water, is less likely to fall apart and holds its color better. But that's not all.
Despite the longer cooking time, nutrients and flavor are retained better by food cooked in steam rather than immersed in boiling water.
Those reasons alone are enough to make it the best way to cook a number of vegetables and in particular some of the more delicate ones such as asparagus, broccoli and green beans.
The process is simplicity itself. Bring some water to boiling point, put a steamer over it, add the vegetables to the steamer and cover. Test with a wooden skewer from time to time to see if they are done.
Note: green beans will retain their color when cooked in steam, even if they are covered. Do not cover them when cooking them in boiling water. They will oxidize and turn an unattractive grayish color.
Points to Watch
Make sure that the steamer you are using is big enough for the job. If the vegetables are packed in too tightly then the ones at the bottom are going to cook much quicker than those at the top.
Obviously you don't want the vegetables to come in contact with the boiling water so make sure there is plenty of room between the water and the bottom of the steamer.
Adding salt to the water is pointless, so don't bother. However adding the greens from cauliflower to the water does improve the finished flavor. Don't ask me why. It just does.
There is always a risk that your water will dry up and your pan will get burnt. To avoid this, put a marble or small pebble in the water. If the level drops too much you will hear it. As a matter of fact, your neighbors will probably hear it!
Take great care when removing the lid from a steamer and make sure your hand is protected in some way. That first rush of steam is at boiling point and there's a lot of it. It hurts, believe me, I've got the scars to prove it.
What Type of Steamer
It doesn't really matter.
I use a bamboo one which I bought in a Chinese market for next to nothing and it's terrific. Part of its charm is that, for a few cents, you can keep adding extra layers to it until the whole thing resembles a kind of cylindrical pagoda.
This means that you can start cooking the food which will take longest in one layer, then add the other layers, bit by bit, according to each ingredient's required cooking time. It's then simple to ensure that all your vegetables (and anything else you may be steaming) are ready at the same time.
But you don’t need something like that to start with. You could also use a colander fitted inside a suitably sized saucepan and covered with the saucepan lid.
There are even stainless steel baskets available which are designed to fit just about any size of saucepan and can double up as a colander.
Above all, you do not need to buy some expensive electrical gadget which you will only use a couple of times a month. In fact, I'll go further - they are an unnecessary waste of money.
Incidentally, even if you prefer to boil your potatoes, it's a good idea to drain them when cooked, return them to the saucepan and then cover them with a clean tea-cloth until you are ready to serve them.
Doing this steams them for a bit which will produce a lighter, floury finish that also works very well if you intend to mash or cream them.
