How Old is your son now? Actually to me I dont't give porridge everyday as a source of carbo. I give potatoes, sweet potato, bread. If you r asking about soup stock for porridge wht I do is I boil one batch for about 3 days amount. I use vegetables stock with carrot, corn, onion, celery, chicken bones, or I have wintermelon soup, lotus root soup, normal chicken stock. I will discard everything from the soup n only keep the soup itself n add in fish, chicken, veg like carrot, pumpkin, brocolli, spinach in it.