How to make vegetable stock

Why the timing is different

A chicken stock takes hours because collagen has to convert to gelatine, and that is slow. Vegetables have no collagen. Their flavour compounds are water-soluble and come out within thirty to forty-five minutes.

Beyond about an hour, nothing more is extracted and things start going the other way: vegetables break down, the stock goes cloudy, and certain compounds turn bitter or sulphurous.

The other consequence is that vegetable stock has no body. It is flavoured water, and a sauce made with it will not thicken the way one made with chicken stock does. Reduction, a little starch, or a puréed vegetable are the ways round that.

What to use and what to avoid

• In: onion, leek, carrot, celery, fennel trimmings, celeriac, parsley stalks, bay, thyme, peppercorns. The reliable base.
• In: dried mushrooms, which add depth and glutamate and are the single best addition.
• In: tomato or a little tomato purée, for savouriness and colour.
• In: kombu, which contributes glutamate and makes a remarkably good quick stock.
• Avoid: brassicas. Cabbage, sprouts, broccoli and cauliflower go sulphurous.
• Avoid: potato and other starchy vegetables, which cloud it.
• Avoid: beetroot unless you want everything pink, and avoid too much carrot, which makes it sweet.
• Avoid: anything past its best. A stock made from vegetables on the turn tastes of vegetables on the turn.

The method

Forty-five minutes, start to finish. Cooling, storing and reheating a stock or broth safely is a food-safety matter rather than a question of taste, and the Food Standards Agency is the authority on it. Follow its guidance rather than a recipe timing.

1. Chop the vegetables roughly. Smaller pieces extract faster, which matters over a short cook.
2. Optionally sweat them in a little oil first. This deepens the flavour considerably and is worth ten minutes.
3. Cover with cold water — not too much, or the stock is weak. It should barely cover.
4. Bring to a bare simmer and cook, uncovered, for thirty to forty-five minutes.
5. Add delicate herbs in the last five minutes rather than at the start.
6. Strain through a fine sieve without pressing the solids.
7. Reduce afterwards if you want it stronger. Cool quickly and refrigerate or freeze.

Giving it body

Reduction

Concentrates flavour but adds no viscosity, since there is no gelatine.

Puréed vegetable

A little cooked onion, carrot or potato blitzed in gives body. It also clouds the stock.

Starch

Cornflour or a roux where a sauce needs thickening.

Dried mushroom or kombu

Add savoury depth rather than body, and both make a thin stock taste substantial.

Roasting the vegetables first

Gives a darker, deeper stock closer in character to a brown meat stock.

Common questions