सोडियम साइट्रेट (Trisodium citrate dihydrate (sodium citrate))

Sodium citrate usually means trisodium citrate, made by neutralising citric acid (nimbu ka sat) with a sodium base. Food labels list it as acidity regulator INS 331. It has a mild salty, slightly sour taste.

• Formula: Na3C6H5O7·2H2O (the common dihydrate)
• CAS number: 6132-04-3 (dihydrate); 68-04-2 (anhydrous)
• Molar mass: about 294.1 g/mol (dihydrate)
• Appearance: white granules or crystalline powder, odourless
• Solubility: very soluble in water. The solution is mildly alkaline, so it can raise the pH of acidic foods.

In cheese, it binds calcium and loosens the protein network. That stops the fat from separating when cheese melts.

Both Azlok listings are food grade sodium citrate, in 350 g and 700 g packs.

Food grade means it's meant for use in food. It must still be used within the limits set by FSSAI for each food category. Check today's price per kg for both packs.

• Cheese sauces and processed cheese: an emulsifying salt that keeps melted cheese smooth for nachos, mac and cheese, and cheese dips.
• Drinks: buffers the sourness of citric acid in soft drinks, nimbu-flavoured drinks and electrolyte-style beverages.
• Jams, jellies and dairy: controls acidity so pectin sets properly, and stabilises milk proteins in some dairy products.
• Lab: used to make citrate buffers, and is one of the ingredients of Benedict's reagent for sugar tests.
• Cleaning and industry: a phosphate-free builder in detergents. It binds calcium and magnesium in hard water.

Smooth cheese sauce: a widely shared home recipe uses about 10–11 g of sodium citrate for 280 g of grated cheese and 260 mL of milk or water. That's roughly 4% of the cheese weight.

1. Dissolve the sodium citrate in the warm liquid in a pan.
2. Bring it to a gentle simmer.
3. Add the grated cheese a handful at a time, stirring or blending until smooth.
4. Adjust thickness with more liquid or cheese. Don't add more citrate than needed, as too much tastes salty and soapy.

Drinks and preserves: it's usually added in small amounts alongside citric acid to soften sharp sourness. Follow your recipe and FSSAI limits for the product category, especially if you sell what you make.

Weigh it: use a kitchen scale reading to 1 g. Spoon measurements vary too much for small amounts. As a rough guide, a level teaspoon of granules weighs around 4–5 g, but check your own spoon once on the scale.

• Sodium citrate is a permitted food additive, but use it only in the amounts a recipe needs. It adds sodium to the food.
• The powder can irritate eyes. Avoid blowing dust around and rinse with water if it gets in your eyes.
• Keep it away from strong acids and strong oxidisers. Store it on a food shelf, not next to cleaning chemicals or pool supplies.
• Use clean, dry spoons. Moisture makes it cake, and wet spoons bring in contamination.
• Store it in an airtight, labelled container in a cool, dry place, away from non-food chemicals like washing soda.
• Keep it away from children.
• Small amounts can go down the drain with plenty of water.

For anything that goes into food, buy only food grade sodium citrate, which is what Azlok lists. Don't substitute lab or technical sodium citrate in a kitchen. If you're making cheese sauce now and then, the 350 g pack will last months. A café or cloud kitchen making sauce daily will find the 700 g pack more practical.

If you sell food made with it, check your own FSSAI licence and labelling rules, and keep the supplier's batch details. Food businesses needing 25 kg or more can ask for a quote through bulk inquiry.