How do you make sure a white sauce is smooth?

There are several tips and techniques to ensure a white sauce is smooth and lump-free:

1. Use the Right Ingredients:

- Use high-quality ingredients such as fresh milk, butter, and flour.

- If you're using all-purpose flour, sift it before measuring to remove any lumps.

2. Start with a Roux:

- A roux is a mixture of butter and flour cooked together. It helps to thicken the sauce and prevents lumps from forming.

- Melt the butter over medium heat, then gradually whisk in the flour. Cook the roux for a minute or two, or until it's golden brown.

3. Gradually Add Milk:

- Slowly whisk the hot milk into the roux, a little at a time. This prevents the milk from curdling and ensures a smooth sauce.

4. Constant Whisking:

- Continuously whisk the sauce as you add milk. This helps to incorporate the milk evenly and prevents lumps.

5. Use a Whisk:

- A whisk is the best tool for making a smooth white sauce. It allows you to distribute the heat evenly and break down any clumps.

6. Avoid Boiling:

- Do not let the sauce boil. High temperatures can cause the sauce to curdle and become grainy. Simmer the sauce gently until it reaches the desired consistency.

7. Seasoning:

- Add salt, pepper, and other seasonings to taste once the sauce has thickened. This helps to enhance the flavor without affecting its smoothness.

8. Strain the Sauce:

- If you notice any lumps in the sauce, strain it through a fine-mesh sieve. This will remove any remaining lumps and make the sauce silky smooth.

9. Off-Heat Thickening:

- If the sauce is still too thin after simmering, remove it from the heat and whisk in a small amount of cornstarch or arrowroot powder dissolved in a little cold milk. This will help to thicken the sauce without the risk of curdling.

Remember, practice makes perfect. With patience and attention to detail, you'll be able to create smooth and delicious white sauces every time.