Sealing and Resealing Natural Stone Worktops

Pour a tablespoon of water on the worktop and leave it fifteen minutes. If the stone darkens where the water sat, the seal has worn through and it is time to reseal. Doing this test twice a year takes two minutes.

It depends on the stone and the traffic. Dense granite might go two to three years; a soft, light marble around the sink may need doing annually. Heavy use and frequent cleaning both shorten the interval.

Clean and fully dry the surface, apply an impregnating sealer evenly, let it dwell for the time on the tin, then buff off every trace of residue before it cures. Residue left to dry is what creates a patchy, hazy finish.

Marble etches on contact with acid, and lime, tamarind and vinegar are everywhere in Thai cooking. Sealing slows staining but does not prevent etching, so honed finishes and a realistic attitude to patina matter more than any product.