Yes, pastes should generally be seasoned before storage. Seasoning before storage allows the flavors to meld and develop more fully over time, resulting in a more flavorful final product.
Seasoning pastes before storage is a crucial step in maximizing their flavor potential. When you add salt, herbs, spices, and other flavorings to a paste and then store it, several things happen. First, the salt helps to draw out moisture from the ingredients, which can help to preserve the paste and prevent spoilage. Second, the flavors of the various ingredients have time to interact and blend together. This process, known as flavor melding, results in a more complex and nuanced flavor profile than if you were to add the seasonings just before using the paste. For example, if you're making a garlic-ginger paste, the garlic and ginger will infuse each other, creating a deeper, more harmonious flavor. Finally, seasoning before storage ensures that the seasoning is evenly distributed throughout the paste, preventing some parts from being overly seasoned while others are bland.
When seasoning pastes for storage, start with a conservative amount of salt and other seasonings. You can always add more later when you use the paste, but it's difficult to remove excess seasoning. Taste the paste after a day or two in the refrigerator and adjust the seasoning as needed.