Yes, adding a tiny amount of sugar or a sweet element to broth can be useful to balance acidity, enhance savory flavors, or create a more complex and rounded taste profile. This is often done in Asian-inspired broths or when the broth contains acidic ingredients like tomatoes.
The addition of a small amount of sugar to broth serves several purposes. First, it can help to counteract excessive acidity. If your broth contains ingredients like tomatoes, vinegar, or citrus juice, a pinch of sugar can soften the tartness and create a more harmonious flavor. Second, sugar can enhance the savory notes in the broth. It works by a principle similar to adding salt – a small amount can bring out the other flavors and make them more pronounced. This is particularly effective in broths that contain umami-rich ingredients like mushrooms, seaweed, or meat. Finally, a touch of sweetness can add complexity and depth to the overall flavor profile. It creates a more nuanced and interesting taste experience, preventing the broth from tasting flat or one-dimensional. The key is to use it sparingly; you shouldn't be able to detect the sugar directly, but rather notice an overall improvement in the broth's balance and flavor. Common sweet elements used include white sugar, brown sugar, honey, maple syrup, or even a small amount of mirin.
When adding sugar to broth, start with a very small amount (e.g., 1/4 teaspoon per quart) and taste as you go. It's much easier to add more sugar than to remove it if you overdo it.