Properly fermented appam batter will have a slightly sour aroma, a frothy or bubbly appearance on the surface, and a light, airy texture when stirred. The batter should have increased in volume.
Fermentation is crucial for achieving the characteristic soft center and crispy edges of appam. Here's how to determine if your batter is properly fermented:
Visual Inspection: Look for small bubbles throughout the batter and a frothy layer on top. This indicates that the yeast and bacteria are actively producing gas.
Aroma: A slightly sour, tangy smell is a good sign. This is due to the production of lactic acid during fermentation. If the batter smells overly pungent or rotten, it's likely spoiled and should not be used.
Texture: The batter should be light and airy. When you stir it, it should feel less dense than when you initially mixed it. The batter should have increased in volume, typically by about 50% to 100%.
Taste Test (Optional): A tiny taste can confirm the sourness. However, this is not always necessary and should be done cautiously.
If the batter doesn't show these signs after the expected fermentation time (usually 8-12 hours, depending on the temperature), it may need more time or the yeast may not be active.
In colder climates, place the batter in a warm spot (like near a preheating oven or inside a slightly warmed oven that is turned off) to encourage fermentation. Avoid placing it in direct sunlight, which can overheat the batter and kill the yeast.