You do not need. Sometimes I'm there for my porridge six months old son in, but long he keeps not warm. And what I find not so good: The thread of the lid is on the inside, so that at full filling of the whole mash in the thread adheres to the open, so more of a smear around. And then go. : -S In addition, no not even really fits much purity an entire serving. I would not buy again are more in the closet as I use them.
