Going with, not against, the grain
I am a bit confused about the differences between couscous, Israeli couscous and quinoa - are they interchangeable in recipes? I've seen salads in shops using a big fat bulgur wheat too, is that the same as these other grains? And why is polenta in a restaurant sometimes creamy, almost soupy, but at other times firm and fried into chips? How are they cooked differently?
Think of grains as you would vegetables, fruit, pulses or salad ingredients. They all have their own individual characteristics - it's not as though they're all the same just because they are a grain.
Although it's worth pointing out that couscous and Israeli couscous are not grains as such. The former is made by removing the bran and germ from durum wheat, in itself a cereal grain, leaving the endosperm or starch and then crushing this into semolina. If it's ground super fine, it becomes flour. Israeli couscous is in fact a type of pasta produced by mixing flour and water into a paste and forming the little balls you're familiar with, often pre-toasted before being packaged.
And while quinoa is a seed, it's actually termed a pseudocereal as it's neither a cereal nor a grain, as these must (technically) come from members of the grass family.
Quinoa is in fact closely related to spinach and tumbleweeds - who knew? Buckwheat is another seed, another pseudocereal that we think of as a grain, and it's closely related to rhubarb. But enough of the science of plants. For argument's sake let's think of all these delicious and nutritious seeds, byproducts and whatevers as "grains". Because that's what we find them under in the aisles of shops and supermarkets.
As to how you use them and are they interchangeable - that's really, entirely, up to you. If you were to think of quinoa and barley for example, they have absolutely nothing in common. One is small and slightly nutty in taste, with little starch. The other is large, chewy, quite gloopy at times if overcooked. Could you replace one with the other? Yes. Would they give the same result? No. But then that's neither here nor there when you're creating a dish, because you can mix things up (replace basil for thyme, apples for pears) and yet still end up with a nutritious dish. Bulgur wheat is simply cracked whole hulled wheat that has been parboiled before being packaged and is a terrific grain to cook with as it always retains a lovely crunchy texture with a good amount of chew as well.
The problem I often have with grains is that people often overcook them to the point where their texture disappears and they become almost pasty. The key is to cook them until they won't crack your teeth but not to the point of paste. If you've cooked them to the right degree, it helps to drain them in a sieve or colander and lay on a tray to cool rather than rinse in cold water, which will wash away some of their nutrients and minerals.
Polenta was historically made from barley until maize was introduced into Italy (and other European countries) from the New World in the 16th century. It's hard to believe it was ever made without the cornmeal we now think of. As to whether it's served runny like porridge or set like chips, that's easy. Next time you make a pot of soft polenta and you have some left over, tip it into a baking dish or on to a plate and as it cools it will set and become firm. This can then be refrigerated and cut into whichever shape you like before being deep-fried, pan-fried or baked in the oven.
In our Ask Peter series, executive chef Peter Gordon answers your curly culinary questions. If you're stumped over something food-related, send your question to firstname.lastname@example.org and keep checking in for answers. You can read more on Peter on his website, have a read of his Ask Peter articles or check out his recipes on our site.