Symbolism, Imagery, Allegory
Yup: the least appetizing meal in Jane Eyre is also one of its most potent symbols. We really wish we could be writing about a bacon cheeseburger.
There are two important moments when (really nasty) porridge figures in Jane’s life. The first is at Lowood, when Jane arrives and, along with the other girls, is served burned porridge for breakfast. It’s so disgusting that nobody can eat it, and Miss Temple ends up giving the girls an extra meal during the day to make up for it, which pisses off Mr. Brocklehurst.
The second is during Jane’s period of homeless wandering, when a woman and a little girl tending a pig give Jane a bowl of cold, hard, congealed porridge that the pig wouldn’t eat. And pigs eat everything.
So what does it symbolize? Well, basically, a level of humility and subjection that’s unnatural for anyone to attain. Mr. Brocklehurst thinks that if the girls are served inedible porridge they should either 1) eat it and be grateful anyway and "mortify the flesh" or 2) go hungry and use the opportunity to "mortify the flesh." (He's big on the whole mortifying flesh thing.)
We can tell, however, that he’s never missed a meal in his life and that either of those options is a cruel martyrdom, not a real opportunity for spiritual growth. When Jane is forced to take the congealed porridge and be grateful for it later in the novel, we realize she’s been brought down to the very low level that someone like Mr. Brocklehurst (or Mrs. Reed!) wanted her to occupy.
We’re meant, of course, to be super alarmed about this. Because the reader knows (even if no one else does) that Jane Eyre is one kick-butt heroine, and that a just world would see her eating caviar.