Pressing on the solids when straining broth can force small particles through the strainer, clouding the broth, and release bitter compounds from the vegetables, negatively impacting the flavor and clarity.
When making broth, you simmer ingredients like bones, meat, and vegetables to extract their flavors. After simmering, the solids need to be removed to achieve a clear and flavorful broth. Straining is the process used for this. However, aggressively pressing on the solids during straining can have undesirable consequences.
Here's why you should avoid excessive pressing:
Cloudiness: Pressing forces tiny particles of sediment and finely ground ingredients through the strainer. These particles, which would otherwise remain behind, cloud the broth, making it less visually appealing. A clear broth is often desired, especially in professional cooking.
Bitter Flavors: Vegetables, especially those from the brassica family (like broccoli or cabbage), contain compounds that can become bitter when overcooked or aggressively squeezed. Pressing on the solids releases these bitter compounds into the broth, negatively affecting its taste. Similarly, some herbs can also impart a bitter taste if handled roughly.
Unpleasant Texture: Even if the particles are small enough to pass through the strainer unnoticed, they can still contribute to a slightly gritty or unpleasant texture in the final broth.
Instead of pressing, allow the broth to drain naturally through the strainer. If you need to speed up the process, gently agitate the solids with a spoon or ladle without applying significant pressure.
For an exceptionally clear broth, use a cheesecloth-lined strainer. The cheesecloth acts as a finer filter, trapping even the smallest particles and resulting in a pristine, clear liquid. Avoid pressing on the cheesecloth as well!