Skimming

Two things rise, and they are not the same

The grey-brown foam that appears in the first twenty minutes of a stock or a stew is coagulated protein and other soluble matter released as the food heats. It is not harmful and it tastes of very little, and if left it breaks up and disperses, which is what makes a stock cloudy.

The fat is a separate matter. It rises steadily throughout and does not disperse in the same way, and it carries a great deal of flavour. Removing all of it is usually a mistake; removing most of it from a fatty braise usually is not.

So the scum is worth taking off promptly and the fat is worth taking off at leisure — ideally the next day.

Skimming scum

Only worth doing in the first half hour, and only if clarity matters.

1. Start the pot with cold water and bring it up slowly. Proteins coagulate gradually and rise as a raft rather than dispersing.
2. Do not let it boil. A boil breaks the raft up and pushes it back through the liquid.
3. Skim with a wide flat spoon or a ladle, taking the foam off the surface without stirring.
4. Wipe the spoon between passes rather than putting the scum back.
5. Add the aromatics only once the skimming is done — otherwise you spend the next ten minutes fishing out bay leaves.
6. After about half an hour there is little more to come. Stop and leave it alone.

Removing fat

In descending order of how well each works.

• Chill it overnight. The fat sets in a sheet and lifts off in one piece. Nothing else comes close.
• A fat separator jug, which pours the liquid from underneath and leaves the fat behind.
• Let it stand and tilt the pan, spooning fat off from where it collects at the shallow edge.
• Drag a ladle across the surface, rim just below the liquid, letting fat run in.
• Lay kitchen paper flat on the surface and lift it off. Repeat with fresh sheets.
• Ice cubes briefly in the liquid, which congeal fat onto them for lifting out.
• Keep what you remove. Strained beef, lamb, duck and chicken fat are all worth having.

When not to skim

A curry or a rich stew

Oil separating at the surface is often the sign it is finished, not a fault.

A brief pan sauce

The fat is part of the sauce and skimming it removes the point.

A soup you want rich

A thin slick carries a great deal of flavour.

Anything already lean

There is little to remove and it is not worth the effort.

A rolling boil

Skimming a boiling pot achieves almost nothing — the foam has already dispersed.

Jam

A knob of butter at the end disperses the scum and saves skimming entirely.

Common questions