The Science of Steam Cooking
If you think of the number 100, you are not likely to be reminded of the delightful taste of lightly cooked stuffed ravioli, crisp vegetables in olive oil or tender flavour-packed fish fillets. And yet, the number 100 plays a fundamental role in dishes such as these. Has anything come to mind? Exactly: the temperature of boiling water. Once it reaches 100°C, this precious liquid turns into steam – its gassy form – and becomes the preferred cooking method for a healthy diet, but this does not necessarily mean that it is less tasty: steam cooking, that is. Don’t underestimate it. Today, we shall be presenting some convincing arguments.
First of all, just consider the "magic" of steam: its maximum temperature coincides with that reached by water in its phase of transformation, in other words 100°C. This is what happens in normal conditions, that is to say, when pressure is around one Atm. If the pressure increases, so does the temperature of aqueous steam and this is the principle underlying the working of pressure cookers. So steam cooking makes use of the most ordinary steam at 100°C, so long as you have atmospheric pressure: all you need is a pan and a basket and you can get started.
Consequently, there are two advantages. The first is that, in steam cooking, the water comes into contact with the food in a gassy form, without immersing it in liquid. The water does not become “dirty” so there is no “boiling-point elevation” and the temperature remains practically constant.
The second advantage is that the aqueous steam cooks food while preserving its moisture. It is hard to imagine a more natural, healthy and flavour-friendly cooking method than steaming. Since there is no immersion, as in boiling, most of the nutrients and molecules responsible for providing food flavours remain, without being dispersed in the liquid. On the basis of this principle, we can draw up some rules for steaming food properly.
First of all, make sure there is plenty of water under your basket. In this way, even if the liquids released by the food fall into the pan or into the dish, the variation in temperature will be negligible. Another important recommendation is not to salt the water: this is a common error which actually serves no purpose. The steam released is nothing but water, in any case, and if you add salt you will only delay evaporation: to add flavour, add salt to the food once it is cooked.
At this point, choose your ingredients carefully: red meat for instance does not lend itself well to steam cooking. Chicken morsels are preferable, but vegetables, potatoes, fish and rice work the best. Try cooking some simple broccoli, for instance: you will not believe the taste. When steaming fish, learn to aromatise the cooking liquid. Use one part white wine to four parts water, adding spices and herbs such as pepper grains, bay leaves and thyme.
Finally, always bear in mind that steaming is fast, and takes no more than a few minutes. The ingredients have to be selected on these grounds.
Would you like a recipe to try as you learn? Let’s borrow a recipe from the region of Campania: a traditional Christmas salad[1] called "insalata di rinforzo". Cut about 1kg of white cauliflower into pieces and steam for around ten minutes. Then put it all into a bowl. Add 100g of black olives, a few anchovy filets preserved in oil, mushrooms and artichokes (also preserved in oil), 100g of green olives and 50g of capers preserved in salt, taking care to rinse them thoroughly.
Season with plenty of olive oil, three spoonfuls of white wine vinegar, salt and pepper. Leave the salad to rest in the fridge for a couple of hours and, when you are ready to serve, add some escarole salad leaves. Who said steamed food was boring?
References
- ^ traditional Christmas salad (www.finedininglovers.com)