Two ideas for tea bags

  1. A bag that is lined with a shape memory alloy. The ring is small when cool allowing tea to move freely. As it warms up in the water, it expands thus squeezing the tea and extracting the water left. I think I've seen this somewhere before but haven't been able to find it.
  2. A tag that changes color with exposure to air. The tag can start normal and go clear in the same amount of time as the recommended brew time.