Use visual cues if your waffle iron doesn't have an indicator light or sound. You'll see steam escaping while the waffle cooks—this shows the batter expanding and filling the cavities. As the leavening agents react to heat, bubbles form, causing the batter to rise and set. Once the steam stops, it's a sign your waffle is likely done. Check the color and texture, and if needed, cook for another minute or two until it reaches your preferred crispness.