Sealers

Sealers are used to protect concrete countertops from kitchen culprits and oils. Two types of sealers are commonly used on concrete counters. The first is a penetrating sealer that flows into the concrete’s pores and seals them. The other type leaves a coating film on top of the concrete, creating a physical barrier between the concrete and contaminants. Coating sealers, such as wax, must be applied on a regular basis. While these supply a high level of protection, they are not impermeable.
"Sealers make the concrete stain-resistant, but not stain-proof". There is no rule how often to apply sealer. Counters can be given a coat of surface sealer once a month for more protection, or just once every few months. "The penetrating sealer protects the counter and the wax protects the sealer".

Before applying a surface sealer, the counter should be clean, dry and free of old contaminants. Read the manufacture’s label instructions before applying it. Sealers that coat the surface of counters repel liquids, causing them to bead up. "When liquids don’t bead up anymore, it’s time to reseal". Another way to tell counters need resealing, is to watch for worn spots. "You’ll see that the sealer is wearing down, similar to worn spots on the finish of a wood floor".