Granite should be sealed before it is used to avoid colored fruit juices and cooking oils from seeping into small fissures and cracks. You should only use a high-quality granite sealer, available at most home improvement stores, or at European Marble and Granite. They have a life span of upto ten years.
One of the most important phases of the sealing process, is the thorough and complete cleaning and removal of any residue from the stone surface.
After a thorough cleaning, let it dry for 24 hours before applying the sealer. Then apply the sealer and let it dry. Once the sealer is dry, buff it off with an old terry-cloth bath towel.