So, what is a stock?
At the most basic level, a stock is a flavourful liquid made by simmering various ingredients in water for a long duration. They can be meat, seafood or vegetable stocks and flavoured with any number of herbs and spices. This liquid is then used in other recipes, bringing an intense concentration of flavour to the dish.
They can also be called fond, broth, bouillon, fumet, and nage which all mean generally the same thing, but with slight variations. Broths are made with meat while stocks are made from only nones. Bouillon – from the French ‘to boil’ – refers to anything simmered in water. Fumet is a concentrated flavour often with wine. And finally a Nage refers to broth flavoured with white wine, vegetables, and herbs usually used to poach seafood.
Stocks can be either white or brown, white stock is clear and subtly flavoured whereas brown stocks use roasted ingredients to create a more robust and complex flavour.
What can go into a stock?
The most classic ingredients of a stock are usually bones, a mirepoix (a mix of onion, carrot and celery), herbs, spices, and sometimes tomatoes (in brown stocks) and wine. But stocks can really be made with anything you have lying around and are a great way to get rid of cuttings and vegetable peels in a sustainable way.
Meat trimmings can also be added but try not to use the fat and gristle too much as it can make the stock congealed and cloudy. When making a bone-based stock, it’s better to start with clean bones that have been blanched for 5-10 minutes in boiling water to remove the impurities. Cutting open the bones also helps extract the most flavour.
For seafood stocks, it’s a little trickier. Lean and neutral fish bones are preferred – fatty fish like salmon and tuna can produce an overly assertive flavour. Fish heads and tails are also often favoured for making stocks but try to exclude the gills which tend to be a little pungent. For shellfish, the heads, tails, shells and trimmings are all exceptionally well suited to creating a rich stock.
How to make a stock
Low and slow is the fundamental rule when it comes to a stock. It’s always simmered gently to extract the full flavour but never boiled. Use a tall pot to minimise the amount of liquid lost to evaporation. Starting in cold water helps in opening up and releasing the impurities from the bones caused by the breaking down of proteins. The impurities will rise to the top and should be skimmed from the surface.
If you’re making a white stock, the mirepoix is added at the end of the process for a fresher flavour. But for brown stock, the mirepoix needs to be roasted at the beginning with the bones.
Similarly for other vegetables, herbs and spices, the rule of thumb is to add all the ingredients to roast in the pot first for brown stocks and throw them in later for white stocks.
The general wisdom is that fish and vegetable stocks take about 45 minutes to an hour, poultry stock takes about four and meat stocks take up to eight hours. The deciding factor in the length of cooking, especially for meat and poultry stocks, is actually the size of the bones and other ingredients. The smaller the cuts, the less time it takes to extract all the flavour.
When it’s ready, let the stock cool and strain it out through a cheesecloth or very fine strainer into freezer-safe containers. If you’re not using it immediately, cool the stock completely and freeze it for up to 3 months.