Natural-stone floors and countertops in the kitchen are a dream come true for many homeowners, but this happens to be the living space where food spills are most likely to happen. The chemical composition and porosity of natural stone makes it vulnerable to staining by various foods, and the problem can be traced to certain organic compounds and the chemical reactions they cause.
As the most consumed beverage in the world, tea is filled with tannin, an organic compound present in many plant species. Extraction of tannin from tree bark to darken leather is a practice that dates back to medieval times. When tannin molecules come into contact with natural-stone surfaces, there’s more than staining to worry about. This compound has astringent properties, which means it’s also acidic and can cause etching.
The best way to protect against stains on natural stone is to keep the stone properly sealed. Here’s a quick video explaining how to use Granite Gold Sealer®:
Tannin is also present in coffee, and its staining potential is even greater when beans are thoroughly roasted and percolated to make American-style coffee. Coffee that has been sitting in the coffeemaker decanter for hours has even more staining power.
The purple grin that results from a wine tasting tour is caused by chromogens, which are also found to a certain extent in coffee and tea. A chromogen can be produced by organic or synthetic means, and its invariable property is to cause a chemical reaction to bind pigment molecules together. As for the pH level of red wine, it typically ranges between 3 and 3.9, which is about the same level of acid rain, a known enemy of natural-stone structures and sculptures in outdoor settings.
4. Citrus Fruits
Citric acid in oranges, lemons, and grapefruits makes them taste tangy, and it can also be corrosive. Stains from acidic citrus fruits can cause a dull appearance and etch the stone.
Depending on their ripeness and origin, mangoes can have pH levels comparable to citrus fruits. The juice of these tropical fruits is loaded with carotene, a natural pigment used to make Yellow Number Five, a popular food coloring ingredient.
6. Tomato Sauce
The tannin and carotene content of tomatoes is as high as that of grapes, prunes, and carrots. The preparation of tomato paste and sauce releases lycopene, an antioxidant that binds both protein and pigment molecules.
7. Chinese Takeout
The American-Chinese style of cuisine developed by immigrant restaurant owners in San Francisco in the 19th century is certainly delicious, but it also happens to contain many ingredients that can quickly stain natural stone. Soy sauce, teriyaki flavoring, cashew oil, ginger and curry paste, food coloring, and the apricot jam used to make duck sauce are all substances you need to make sure to clean up quickly if they come into contact with your stone flooring and countertops.
Dealing with Food Stains on Natural Stone
As long as you regularly use a specially formulated granite sealer to keep a fresh and strong seal on your natural-stone tiles and slabs, organic food stains shouldn’t be difficult to take care of. Make sure to wipe spills right after they happen. Should you have to deal with oil stains, they can be removed with a paste made with baking soda and acetone that’s placed on the stain for 24 hours before rinsing with water. Make sure to reseal the stone after. In the case of stains from food substances, soak a paper towel or white terry cloth towel with bleach and leave it on top of the stain for 24 hours before rinsing it with water.
In addition to cleaning and polishing, sealing is one of the most crucial steps in caring for natural-stone countertops. To learn how to seal granite, marble, travertine, and other types of natural stone, reach out to the Stone Care Experts at Granite Gold®. Call one of our friendly and knowledgeable representatives today at 1-800-475-STONE (7866).
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Lenny Sciarrino (aka Lenny S) and Lenny Pellegrino (aka Lenny P) grew up in the family business and are co-founders of Granite Gold®.