Your granite countertop was most likely a beautiful investment in your home and one you intend to maintain as long as possible. While granite is a natural stone--and therefore porous and able to absorb substances that can stain it--sealers help to protect the stone and give you time to wipe up spills. Not every granite is chemically equal, however, so each type of stone requires sealing and re-sealing differently. Learning to protect your stone will help you get the longest life from it.
Test your granite to see if it requires resealing by pouring a small amount of clean water on the stone and allowing it to sit undisturbed for 20 to 30 minutes. Wipe up the water with an absorbent cloth and examine the stone. If the granite has darkened where the water was, it requires sealing. If the stone has not darkened, it does not require resealing.
Clean the granite counter well before resealing. Spray cleanser evenly onto the surface and buff the stone to remove surface debris, grime, finger oils or other substances that could block the sealer from penetrating the stone. Buff the granite completely dry and wait an hour for any moisture the stone has absorbed to evaporate.
Turn on the kitchen fan and open any nearby windows. Pour the granite sealer into a wide-mouthed bowl or dish. The sealer will have an unpleasant smell, so open the windows to alleviate odors.
Dip the craft brush into the sealer and fully saturate it. Paint the sealer onto the counter by pressing the foam onto the granite gently but firmly. Begin at the back of the counter and pull the brush toward you in slightly overlapping strokes. Be sure to get the edge of the stone as well as the edge on the interior of the kitchen sink.
Allow the sealer to absorb into the granite countertop for 10 minutes. Wipe away the excess with an absorbent cloth, drying the granite completely.