Gretchen said:
...But in a professional kitchen, you would still need to know how to figure out how much food you may need. For the most part, professional kitchens are run on the basis of weights--pastries/baking, for example--and have scales available. ...
my previous post was just to poke a little gentle fun at the fact that the problem as originally stated was a math problem about the correct amount to
use when it was actually phrased with how much to
buy.
it's true that a lot of cooking is done by ratios, both at home and in professional kitchens. on the other hand, there are ways of completely avoiding the need for many of them too. i'd say that as far as rice goes, two of the most common ways i've seen rice cooked in restaurants and hotels is:
plain white rice - a standard amount of rice that the restaurant expects to get them through a typical evening is simply added to a large stock pot of boiling water until the rice is cooked, then drained and allowed to sit for a few minutes before being placed into a bain marie.
pilaf style rice - the rice is cooked directly in the large rectangular bain marie pan to which diced onions, bell peppers, olive oil or whatever is also added. chicken stock is added to cover the rice. the pan is covered with aluminim foil and finished in an oven.
these methods have the advantage of a low risk of scorching as can happen when an exact amount of liquid to rice is used and cooked on the stove top until the liquid has all been absorbed. it happens from time to time that someone may get distracted, forget to reduce the heat, set a timer, etc. if the rice gets scorched, in the best case you may be able to use most of it, but in some cases the entire batch is wasted.
maybe these are considered "tricks of the trade". here's another for our young chef-to-be. if you ever do forget to set the timer after memorizing your formula, keep your ears peeled. in the large-sized stock pot you may be using, you don't want to grab a large wooden stirrer to try to see how much water is left in the bottom of the pot. this will close off all the little vents caused by the boiling water which allow the entire batch of rice to be steamed evenly. in a worst case, the top half of your batch won't be cooked thoroughly, while the bottom half becomes mushy. instead, listen to the bottom of the pot (without getting your ears burned). when you hear the rice start to crackle, the very bottom layer of grains will be starting to form a crispy crust. this is still way before it starts to burn. here in japan, people go crazy over that crispy part of rice, but in your kitchen, you'll only lose a serving spoon sized amount.
