Actually very easy

Vegetable stock

The beliefVegetable stock is assumed to get better the longer it boils.

The truthVegetable stock is at its best at 45–60 minutes. After that it does not get richer; it gets bitter.

1 hour 15 minutes

How to make it

What you need

2 onions, 2 carrots, half a celeriac, 1 leek
2 tomatoes or 1 tablespoon of tomato paste
1 tablespoon of olive oil
2 litres of cold water
2 bay leaves, 8 black peppercorns, a few parsley stalks

How the engine read this list (9 lines)

300 g	Onions	onion
140 g	Carrots	carrot
250 g	Celeriac	celeriac
150 g	Leek	leek
240 g	Tomatoes	tomato
14 g	Olive oil	olive-oil
2000 g	Cold water	water
0 g	Bay leaves	bay-leaf
—	Black peppercorns	black-pepper

An empty weight means that line could not be turned into grams — either the amount is open ("to taste") or the ingredient has no record here. Neither enters the sum as zero; they do not enter it at all.

Chop the vegetables roughly, skins and all. Leave the onion skin on: it adds colour.
Heat the olive oil in the pan and turn the vegetables in it over a medium flame for five minutes.
Add the cold water, tomato and spices. Bring it to the boil and turn it down.
Simmer it 45–60 minutes, and no longer.
Strain it without pressing the vegetables, which would cloud it. Divide into small containers and refrigerate within two hours.

Why it works

Vegetables have no collagen, so there is nothing to gain from cooking them for hours the way meat stock is cooked. What gives the flavour — the sugars in onion, the sweetness of carrot, the volatile compounds in celery and parsley, the glutamate in mushroom and tomato — has mostly gone into the water by 45–60 minutes. After that two things happen: the volatile aromas leave with the steam, and the sulphur compounds of brassicas such as cabbage and broccoli break down into a bitter, cabbagey taste. That is why brassicas stay out of vegetable stock, or go in very sparingly. Turning the vegetables in oil for five minutes first adds a deeper flavour through the Maillard reaction. The ratio matters: 2 litres of water to 1 kg of vegetables; more water and the stock is thin. A dried mushroom or two, or a spoonful of tomato paste, gives the umami closest to a meat stock’s body.

The rough sum

3094 grams going in

539 kcal in total

100% of the mass has figures behind it. This is the sum of what GOES IN rather than of what comes out. Wherever something evaporates, drains or ferments the two differ: a kilo of milk is 150 g of cheese.

Diets it qualifies for

Gluten-free Vegan Vegetarian Lactose-free

Storage & shelf life

How long it keeps

Fridge, 0–5 °C: 48 hours
Freezer, in portions: 3 months
Room temperature: At most 2 hours to cool

Vegetable stock looks more innocent than meat stock but follows the same rule: a cooked liquid, into the fridge within two hours, eaten or frozen within 48. That is the UK Food Standards Agency’s advice for cooked food.

When to bin it A sour or yeasty smell, foam or cloudiness: throw it out.

History

Where it comes from

Vegetable stock began as the poor relation of meat stock and gained its place in Europe in the “lean” kitchen of fast days: when meat was forbidden, soups and sauces were built on vegetable stock. In Turkish cooking it goes into the meatless versions of olive-oil dishes, vegetable pilafs and yayla soup; its onion, carrot and celery are the same trio as the French mirepoix.

The knack

Keep a bag in the freezer and collect onion skins, carrot ends and parsley stalks through the week; when it is full, make stock.
Salt the dish the stock goes into, not the stock itself.

The pantry