Double-boiling

Double-boiling is the method of cooking whereby the ingredients are placed in a pot with lid (preferably with double lids) and heated by boiling water in another container (the external container) with lid.

In one of my earlier posts, you saw me using a special apparatus for double-boiling. It is convenient to use but not a must.

Preferably the internal pot is placed on a steel stand rather than by itself in the external container, thus maximizing the surface of the pot in contact with boiling water that surrounds it.

In the above photos, you see me pouring water into the external container, placing a steel stand in it, covering the internal pot with double lids, pointing at the water level, and closing the lid of the external container. The latter is then heated (say, on a stove).

Double-boiling is often adopted for cooking ingredients with high nutrition value. The period of cooking is usually quite long (2 hours in case of the fishhead soup).With double-boiling, the moisture in the ingredients are preserved; and the ingreidents are very slowly cooked to release their nutrients.

The amount of water to be placed in the external container is such that the internal pot is substantially immersed in water. However, leave a certain margin so that the boiling water will not spill over into the internal pot. (You may need to examine it when the water starts to boil, to make sure.)

Water in the external container inevitably evaporates from heating. Since the cooking process is rather long, you need to check the external container (by opening its lid to see) every now and then to ensure that there is sufficient remaining water in the external container.

Sometimes water in the external container becomes fully dried up (because you did not place sufficient water in the first place) If the external container continues to be heated without water in it, there is real danger of fire hazard. Therefore, if you observe that the water in the external container is becoming insufficient, you should pour in additional water (preferably warm water) to continue with the double-boiling process. Meanwhile let the lid(s) of the internal pot remain closed until the end of the intended boiling period.

I would suggest to use an alarm clock/watch to remind yourself (say, every 20 minutes or so) to see if the water in the external container is drying up, as a preventive measure against fire hazard.

(The special double-boiling apparatus which I use has a timer; and will stop boiling automatically at the end of the intended boiling time or when the water in the external container has dried up, whichever comes earlier. Therefore it is safe and convenient to use.)

In both steaming and double-boiling, the internal container is placed on a steel stand and then placed in an external container with water which is heated to boiling. The differences between the two methods of cooking are as follows:

(a) In steaming, the internal container is not covered whereas in double-boiling, the internal container is tightly covered (preferably with double-lids).
(b) The amount of boiling water in the external container for steaming is much less than that in double-boiling. In steaming, the internal container (usually a plate, rather than a pot) is placed above the water level; whereas in double-boiling, the internal container (usually a pot, always closed) is subtantially immersed in water.
In other words, ingredients are heated mainly by steam in one case; and in the other case, heated mainly by boiling water surrounding the internal pot.
(c) The length of time in steaming is not that long, say, 15 or 20 minutes; so as to preserve the freshness of the ingredients. The length of time in double-boiling is usually long, in terms of hours.

I'm afraid that, once again, my descriptions are making things seem more complicated that they really are.

Next time, I'll talk about the finished dish.