It is most likely due to old or expired leavening agents: Baking powder is responsible for the rise in biscuits. If your baking powder is old or expired, it may not be as effective, leading to less rise in the biscuits. Check the expiration date on your baking powder and or test to see if it is still good. To see if your baking powder is still active, spoon ½ teaspoon of baking powder into a bowl and pour in ¼ cup of boiling water. If the mixture bubbles, your powder is good. If it doesn’t, don't use it.