If you do not let the bread rise what will be different?

If bread is not allowed to rise, it will be denser and have a finer crumb. This is because the yeast in the bread will not have had time to produce carbon dioxide gas, which is what causes the bread to rise. As a result, the bread will be more compact and less aerated. Additionally, the flavor of the bread may be slightly different, as the yeast will not have had time to break down the sugars in the flour.