The two questions we are asked most often are, "How do I know if my countertops need to be sealed?" and "How do you seal a granite countertop?" You can perform a simple test which will indicate whether or not your countertops need to be sealed. Simply pour a small puddle of water on the countertop surface and allow it to set for a few minutes. If the tops are sufficiently sealed the water will bead up on the surface. However, if the water appears to soak into the stone or after wiping up the water the affected area appears to have darkened it’s time to reseal.
Penetrating, food safe sealers are available wherever you can purchase ceramic tile. Lowe's and The Home Depot stock them in their flooring departments. Read the label carefully to determine whether or not the sealer can be used in a food prep area. The container will also note the recommended period between re-sealing (normally 5 to 10 years depending on the warranty offered).
Sealing is a simple process. First, thoroughly clean the countertop surface with water and ph-neutral dish detergent, rinse with clean water and dry. As a final step it’s a good idea to use a cloth saturated with denatured alcohol (available in the paint department) to do a final wipe down. The alcohol will remove any oily residue on the countertop. Be aware, alcohol is extremely flammable, make certain there are no open flames in the area.
Then, take a clean, lint free, cotton cloth and dampen it with sealer. Then pour a puddle of sealer about 4 inches in diameter on the countertop. Using the dampened rag spread the sealer out in an area approximately 3 feet wide. Pour another small puddle and repeat the step. Don’t be stingy with the sealer the goal is to get the countertop surface wet so that the sealer will penetrate into the stone.
Do not let the sealer dry on the surface of the countertop. As the sealer evaporates you will notice "pooling,” a spider-web like appearance on the surface. Before the sealer dries apply a second liberal coat. When the second coat begins to pool and before it dries, use a clean terry cloth rag (like an old towel) and give the countertop a good rub down. After the remaining sealer has been wiped up, buff the surface with the towel to remove any haze.
Test your newly sealed countertops with a puddle of water and you should notice a marked difference. If you have any countertop questions send them to firstname.lastname@example.org.