Cheese Sauce, Sodium Citrate

A cheese sauce that will not break, made from any real cheese you like rather than from a processed loaf — and the recipe that runs this whole section’s chemistry backwards.

🔴 Everything else in this collection has been about protecting calcium cross-links. The storage brine adds calcium so a cheese does not dissolve. Halloumi keeps its calcium and refuses to melt. Feta loses it and crumbles.

⭐⭐ Sodium citrate strips them on purpose. It is an emulsifying salt: it binds up the calcium holding the casein micelles together, the protein network comes apart, and the freed casein is then free to do what casein is naturally very good at — emulsifying fat and water. A broken sauce is casein clumping and squeezing the fat out; this stops the clumping at the source.

⚠ It is not an emulsifier itself, and popular explanations garble this constantly. It does not coat anything or hold anything together. It removes the calcium, and the cheese does the rest.

Ingredients

• 9 oz / 265 g cheese, grated — cheddar, gruyère, comté, or a mix; the better it is the

better this is

• 3.5 oz / 100 g liquid — water, milk, beer or stock
• 1/3 oz / 11 g sodium citrate — about 2 to 3% of the total weight
• Optional: mustard powder, cayenne, a grating of nutmeg

Directions

Key ingredients

Salt

1. Grate the cheese. ⚠ Grate it yourself — bagged shredded cheese is dusted with starch or cellulose, which will make the sauce grainy in a way the citrate cannot fix.
2. 🔴 Dissolve the sodium citrate in the LIQUID first, over gentle heat, before any cheese goes in. It has to be in solution to do its job, and adding it to a pan of melting cheese is how you get a gritty sauce.
3. Bring the liquid to a bare simmer, then add the cheese a handful at a time, whisking each addition until it disappears before adding the next.
4. ⭐ It will look wrong and then suddenly right. The first handful may seem to seize. Keep whisking — as the citrate gets to the calcium the sauce goes glossy and smooth, usually quite abruptly.
5. Season at the end, off the heat.
6. ⚠ Do not boil it. A bare simmer is enough, and hard boiling will still eventually drive the fat out.
7. ⭐ It reheats. Unlike a roux sauce it will melt smooth again from cold, repeatedly, which is the other reason to make it this way. It also sets firm enough to slice if you pour it into a lined tray and chill it — that is what a “perfectly melting cheese slice” is.
8. What right looks like: glossy, pourable, completely smooth, and tasting like the cheese you put in it rather than like a sauce.

Notes

Where this recipe came from — and what it is not ⚠ UNTESTED as written, and the ratio is the conventional one: sodium citrate at roughly 2 to 3% of the combined weight of cheese and liquid. Commonly quoted formulas run around 4 g of citrate per 100 g of cheese and 93 g of liquid. Start at 2% and go up — too much reads faintly metallic and slightly soapy.

🔴 Three ways to stop a cheese sauce breaking, and they are NOT the same mechanism This collection now has all three, which is worth laying out because recipes rarely say which one they are using:

Starch. The Army’s 1944 Cheese Sauce builds a flour-and-water slurry; the queso dip tosses cornflour through the grated cheese. The starch physically gets between the proteins and holds water. It works, and it tastes of starch.

Evaporated milk. Both of those use it too, and it is doing real work: its proteins have already been heat-stabilised in the can, and the extra casein dilutes the aggregation.

Sodium citrate. ⭐ The only one of the three that addresses the actual cause rather than working around it — and the only one that adds no flavour and no thickener of its own.

⭐⭐ And this is where the science wing’s calcium argument closes The melting page explains that calcium cross-links hold the protein network rigid, and that pH decides how much calcium stays bound — which is why a high-pH halloumi squeaks and a low-pH feta crumbles. Sodium citrate is that same lever, pulled deliberately and from outside the cheese. ⭐ Four cheeses in this collection are defined by what happened to their calcium, and this sauce is the fifth — the only one where you get to choose.

⚠ On “queso” This is a technique, not a dish. Season it with roasted chillies and it is a queso; with mustard and cayenne it is a Welsh-rarebit sauce; with nothing it is what goes over macaroni. The collection already has a very good queso dip made the starch way, and it is not replaced by this one — they are different tools.

Read alongside the melting page on the site.