This is about the basic cooking ingredient.
In French, the stockpot and its contents are called the fonds de cuisine. The foundations of the kitchen.
All serious cooks will tell you that a good stock is the basis of soups, stews, casseroles, pies and almost every other dish that can be cooked. There is no doubt at all that a chicken soup made using a real chicken stock is entirely different and far better than a chicken soup made from a stock cube.
The same applies to a beef consommé, fish pie or risotto. The flavour of the stock defines the flavour of the dish.
Other good noders have spent their time and effort producing recipes for dozens of types of stock, based on meat, fish and vegetables. I do not propose to add to that excellent body of work.
Instead, I want to explore what stock does, what the flavours are, and some of the short cuts and the strengths and weaknesses of those shortcuts.
I should at this point clarify: stock is, in general, made from bones. Vegetable stock can't use bones, but meat and fish stocks do. The classic demi-glace is traditionally made by boiling the bones of baby cows with wine, herbs and other ingredients and then reducing until the flavour is about as concentrated as it can get. Bones contain gelatin and a good stock should solidify on cooling. The gelatin turns the stock into a gel.
While a liquid based on boiled meat can add great flavour to a dish, the material produced by boiling meat and fat together with other flavourings is strictly called a broth, rather than a stock. A broth tends to be less concentrated and less flavoursome than a stock.
sauth says: To me, the broth vs. stock discussion is more a matter of concentration, not meat vs. bones. Though certainly if you want to end up with a stock, you will NOT boil it to avoid introducing too many impurities, NOT salt it except in the final dish, and cool it overnight so you can defat it (the fat will form a layer on the top) before reducing further to stock concentration. Most of what I know comes from eGullet: http://forums.egullet.org/index.php?showtopic=25256
/me adds, That link points to a great writeup on the use and preparation of stock. Makes my piece almost superfluous. Sigh. Having sighed, I do think that strictly speaking a stock is supposed to gel, due to the gelatin extracted from bones, cartilage and connective tissue, whereas a broth tends to remain liquid. But if a different definition works for you, I'm not going to get into a flame war over it.
All cultures and cuisines have developed their own type of stock made from bones. It is an obvious way of using scarce resources effectively. Instead of throwing away the bones, or feeding them to semi-domesticated animals, the cook boils them up. The resulting liquid can be used to make a thin meal taste better and be more nutritious than it might otherwise be.
In European and North American cultures, where meat is no longer a luxury, many of us throw away the bones and we do not worry about the loss of flavour that ensues. However, in much of Asia and in less wealthy parts of the world, a stock made from meat forms the basis of many dishes based on rice and noodles.
Let us move on a few centuries to the mid-19th century. We find a German chemist by the name of Baron Justus von Liebig working in Paris under the tutelage of Joseph Louis Gay-Lussac. Every student of chemistry has used a Liebig condenser. Although it appears Liebig did not invent this device, it was named for him.
Another of Liebig's many claims to fame — and the one that is relevant here — was to found the Liebig Extract of Meat Company, which later produced the Oxo cube. The company's first factory opened in Uruguay in 1866. At the time, South American cattle were raised mainly for their leather, and not for their meat.
Liebig's idea was to condense the carcasses down to produce a kind of concentrated stock, and ship this back to Europe as a way to create all the flavour of stock, without the hassle.
His belief — mistaken as it turns out — was that by condensing the carcasses down, he could retain all the nutritional value in a concentrated form. Instead, he discovered what the Japanese call umami, which translates as 'delicious savoury flavour.'
Liebig's main product was something akin to the modern-day Bovril. In 1899, the product was re-named as Oxo. Eventually, the company used small amounts of the beef extract and mixed them together with other ingredient to make the stock cube known today as the Oxo cube.
Options in today's kitchen
Moving to the modern day, the lazy and/or ambitious cook now has a variety of options for obtaining a stock.
Professional chefs, serious amateurs and those with a lot of time on their hands will make proper stock. It is the best, but can be time-consuming. Even among professional kitchens, however, there is a rumour that chefs are moving to buying their stocks from specialist suppliers. (source)
Our own resident restauranteur, shaogo says:I've been known to enhance my own quick-cooked (less than 4 hours) beef and chicken stocks with Knorr-Swiss bouillon cubes, which are quite good; but more often than not I make mire-poix and mix that with bones; chicken just gets boiled, beef/veal gets roasted to caramelize in the oven, then boiled (when I say "boil" I mean simmered for at least 5 hours).
Second is the ubiquitous bouillon cube, or 'stock cube' as it is known in the UK. A typical stock cube is made mostly from salt. In 100g of stock cube, there is typically 54g of salt, 20g of sugar, 13g of lactose monohydrate, 8g of fat, 3g of monosodium glutamate and 2g of flavouring. (source)
Before researching this, I had no idea what went into a stock cube, but a quick search revealed the above recipe. I'm not sure I'll be using them again. Ever.
Two alternatives have come onto the market more recently. The first is fresh stock, bought in containers of about 1 litre from upscale supermarkets. These are chilled foods, so should be used within a few days of buying them, but they can be frozen. They are often packaged in plastic sachets or tubs under brands such as Knorr, Kallo or as a supermarket own brand. My experience of these products has been generally positive. More positive with the own-brands and small brands than the international brands such as Knorr, Oxo and similar. As with stock cubes, they can be high in salt, so it's probably best not to add any salt until after the bought stock has been added, and then adjust for flavour.
The second product is a kind of liquid stock cube. This comes in small bottles and has a highly concentrated flavour. Again, they tend to be high in salt, though the flavour varies significantly from brand to brand. In many cases it is not much better than stock cubes.
A third option is powdered stock. Note the Marigold product mentioned below. This is recommended by both DEB and Delia Smith. Read more reviews of the Marigold product here. Unsurprisingly, however, there is great variation in the quality and flavour of other powdered stock additives. Many of them are similar to stock cubes in terms of flavour and ingredients.
As with most things in the kitchen, find an approach that works for you and stick to it.
The Debutante says: I'm a firm believer in Marigold bouillon, and I know quite a few professional and semi-professional chefs who are too. But nothing beats homemade.
Making and using fresh stock
In most domestic kitchens it is impractical to make stock every day. Most people who make their own stock do it each time the bones or carcass become available, and then freeze for later use.
Let me first quote this piece of wisdom from Sneff:
With all stocks, temperature is of the utmost importance, second only to the quality of the raw materials. You will be searching for a temperature that extracts the maximum flavour from the bones and vegetables, without dissolving the gelatin back into the stock at high temperature. If this happens, your stock will be cloudy and somewhat unpalatable. This optimum temperature is always found when the surface of the stock is at a good shuddering simmer, never a rolling boil and never less than a simmer either. Keep this in mind and choose your ingredients carefully and you cannot help but succeed.
Chicken stock is the one most often made at home. This works because the carcass is relatively small and will fit easily into a pan. Preparation takes only a few minutes although the stock needs to boil for two to three some hours. For more meaty stocks, longer boiling is required.
jessicaj says: The longer you simmer stock the richer and more flavorful it becomes. Two to three hours of cook time isn't nearly enough in my humble opinion.
This is an interesting one. Sneff says (and I trust Sneff) that an hour is long enough for a chicken, provided you get the temperature right. But I'm not going to get into recipe discussions. Do what works for you; ignore contradictory advice.
In any case, a common approach is to boil the stock down as far as it will easily go, and then pour the stock into a freezer tray and freeze. Once frozen, the cubes can be put in a plastic bag in the freezer (to release the ice tray for other uses) and used at will. Frozen stock will last a couple of months in the freezer.
Sources, further information