What comes up? Is it acid or whole pieces of food?

If I feed Max right before bed, and he lays down right after he eats, then when he gets up sometimes he just sprays whole chunks out. It's an esophogus problem with him. The food just gets stuck in there and doesn't go all the way down to his stomach. I have gotten around the problem by soaking his food at night, and making sure he walks around a little after eating.