Cornflour Slurry: The Right Ratio for Perfect Thickness

Cornflour slurry is one of the simplest yet most powerful tools in cooking. Whether you are thickening soups, gravies, sauces, or stir-fries, getting the right cornflour slurry ratio makes the difference between a silky smooth finish and a lumpy disaster.

In this detailed guide, you will learn:

• What cornflour slurry is
• The perfect cornflour-to-water ratio
• How to adjust thickness for different recipes
• Common mistakes to avoid
• Pro tips for restaurant-style results

Let’s dive in.

What Is Cornflour Slurry?

Cornflour slurry is a mixture of cornflour (finely ground corn starch) and cold water. It is used as a thickening agent in cooking.

When cornflour is mixed directly into hot liquid, it forms lumps. But when first dissolved in cold water and then added to hot liquid, it thickens smoothly.

The thickening happens because cornflour contains starch. When heated in liquid, starch granules absorb water, swell, and create viscosity. This process is called starch gelatinization.

The Standard Cornflour Slurry Ratio

The most commonly used ratio is:

1 tablespoon cornflour : 2 tablespoons cold water

This ratio works perfectly for:

• Soups
• Gravies
• Stir-fry sauces
• Manchurian sauces
• Chinese-style dishes

Why 1:2 Ratio Works

• It creates a smooth, pourable paste
• Prevents lumps
• Thickens evenly
• Is easy to adjust

Cornflour Slurry Ratios for Different Thickness Levels

Different recipes need different levels of thickness. Here’s a quick guide:

1. Light Thickness (Soups & Broths)

Ratio:
1 tablespoon cornflour + 3 tablespoons water

Use for:

• Clear soups
• Vegetable soups
• Sweet corn soup
• Light gravies

Result: Slightly thick, silky consistency.

2. Medium Thickness (Gravies & Sauces)

Ratio:
1 tablespoon cornflour + 2 tablespoons water

Use for:

• Indo-Chinese gravies
• Chilli paneer sauce
• Sweet & sour sauce
• Restaurant-style curries

Result: Smooth, glossy coating consistency.

3. Thick / Glossy Sauce (Coating Style)

Ratio:
1 tablespoon cornflour + 1½ tablespoons water

Use for:

• Manchurian gravy
• Stir-fry coating sauces
• Sticky Asian-style sauces

Result: Thick, shiny sauce that coats food beautifully.

How Much Slurry to Use Per Cup of Liquid?

Here’s a practical measurement guide:

• 1 cup liquid → 1 tablespoon cornflour slurry
• 2 cups liquid → 2 tablespoons cornflour slurry
• 4 cups liquid → 3–4 tablespoons cornflour slurry

Always add gradually. You can increase thickness, but you cannot easily reduce it.

Step-by-Step: How to Make Perfect Cornflour Slurry

Step 1: Use Cold Water

Never use warm or hot water. It causes premature gelatinization and lumps.

Step 2: Mix Thoroughly

Stir until fully dissolved. The slurry should look smooth and milky.

Step 3: Stir Your Hot Liquid

Ensure your soup or gravy is gently simmering.

Step 4: Add Slurry Slowly

Pour in a thin stream while stirring continuously.

Step 5: Cook for 1–2 Minutes

Let it boil slightly to activate thickening.

Do not overcook — it may thin out again.

Why Cornflour Slurry Sometimes Fails

1. Lumps Forming

Cause:

• Added dry cornflour directly to hot liquid
• Used warm water

Solution:

• Always mix in cold water
• Whisk properly

2. Sauce Too Thin

Cause:

• Too little slurry
• Not boiled enough

Solution:

• Add ½ tablespoon extra slurry
• Let it simmer for 1–2 minutes

3. Sauce Too Thick

Cause:

• Too much slurry

Solution:

• Add warm water or stock gradually
• Stir continuously

4. Sauce Turns Thin Again

Cornflour thickens best at simmering temperature. Overboiling for long periods can break down starch.

Fix:

• Add fresh slurry if needed

Cornflour Slurry vs Other Thickening Agents

Let’s compare cornflour slurry with other options.

Cornflour vs Wheat Flour (Maida)

Cornflour gives a restaurant-style shine that maida cannot.

Cornflour vs Arrowroot

Arrowroot gives a clearer finish but is more expensive. Cornflour is more accessible and stable for everyday cooking.

Tips for Restaurant-Style Glossy Thickness

Want that perfect Indo-Chinese gravy texture?

Follow these pro tips:

1. Use freshly made slurry
2. Always add at the final stage
3. Keep stirring continuously
4. Cook on medium heat
5. Do not add too much at once

Restaurants often add slurry in small portions until the desired consistency is achieved.

Can You Make Slurry in Advance?

Yes, but not for long.

• Use within 30 minutes
• Stir before using (cornflour settles at bottom)
• Do not refrigerate for long periods

Fresh slurry works best.

Cornflour Slurry for Specific Dishes

1. Sweet Corn Soup

Use light ratio (1:3). Add gradually to avoid over-thickening.

2. Chilli Paneer

Use medium ratio (1:2) for glossy coating.

3. Manchurian Gravy

Use thick ratio (1:1.5) for sticky texture.

4. Fruit Sauces & Desserts

Use 1:2 ratio but cook gently to avoid cloudiness.

Does Cornflour Change Taste?

No. Cornflour is neutral in flavor.

However:

• Using too much can create a starchy mouthfeel
• Undercooked slurry tastes raw

Always cook for at least 1 minute after adding.

Is Cornflour Slurry Gluten-Free?

Yes. Cornflour is naturally gluten-free, making it suitable for:

• Gluten-sensitive individuals
• Wheat-free recipes
• Light diet preparations

(Always check packaging for cross-contamination.)

Common FAQs

How long does cornflour take to thicken?

It thickens within 30–60 seconds once heated.

Can I use hot water?

No. Always use cold water.

Can I freeze dishes thickened with cornflour?

Not recommended. Freezing may cause separation.

Can I reheat thickened sauce?

Yes, but add a little water if it becomes too thick.

Science Behind Perfect Thickness

When heated to around 90–95°C:

• Starch granules absorb water
• They swell and burst
• Liquid thickens

If overheated or stirred aggressively for too long, structure breaks down.

That’s why timing is crucial.

Quick Reference Chart

Pro Cooking Checklist

✔ Use cold water
✔ Mix until smooth
✔ Add slowly while stirring
✔ Simmer for 1–2 minutes
✔ Adjust gradually

Final Thoughts

Cornflour slurry may seem like a small cooking step, but it plays a massive role in texture, appearance, and overall dish quality.

Remember the golden rule:

Start with 1 tablespoon cornflour + 2 tablespoons cold water and adjust from there.

Mastering this simple ratio ensures:

• Lump-free sauces
• Perfect thickness
• Glossy finish
• Restaurant-style results at home

Once you understand how it behaves in heat, you can confidently control the texture of any gravy, soup, or sauce.

Now the next time your dish needs thickening, you’ll know exactly how much slurry to add — and why.

Happy Cooking! 🍲