Is Vinegar a Good DIY Cleaning Solution for Granite?
Some great ideas have come out of this trend of lifehack sites and brought with them a resurgence in DIY ingenuity that we love to see. Sites like Lifehacker share great guides and tips, but some other sites or blogs have fallen into the trap of quantity over quality as of late. With that has come the spread of some tips that are not fact checked and can be actively counterproductive to what you're trying to accomplish.
Cleaning granite or any natural stone with vinegar as a DIY solution is one of those ideas. Acidic chemicals and cleaners can not only damage the protective seal of your stone, but their application can result in chemical burns on the surface called etching. So, let's get into why this is, and what you should do instead.
Why Vinegar and other Acidic Cleaners Damages Stone
Most natural stone you might find used for countertops or flooring is an amalgam of several different minerals all tightly packed into solid rock form. One of these minerals is calcium carbonate, which reacts with low pH (acidic) chemicals, dissolving away to leave carbon dioxide and water in its place.
This chemical reaction results in the etching on the surface of your stone, which is permanent physical damage. This isn't only from vinegar, lemon juice or acidic cleaning solutions, but can result from food spills as well. This includes wine, fruit juice, coffee and citrus among others. This is why it's so important to wipe up any spills as soon as they happen, just to be safe.
What Does Etching Look Like?
If the etching occurs as the result of a spill or from cup rings, it can often be mistaken for hard water stains. When used as a cleaning solution and spread around or buffed into the stone, the etching can look like a general hazing or dulling of the surface. Light etching can be somewhat remedied with polishing and buffing the affected area - though in the case of darker stone, the effects of the damage can more easily be seen than lighter shades of granite or marble. In worse cases, we would advise seeking the help of a professional stone restoration specialist.
How To Avoid Etching
The key is to stay proactive in terms of not only immediately cleaning up any spills, but working to prevent them in the first place, as well as making sure to regularly seal your stone. When it comes to food prep or serving on stone surfaces, it's a good idea to use cutting boards, wide serving trays, place mats and drink coasters whenever possible.
Maintaining Your Stone's Seal
Even though they may not look like it, granite, marble and other natural stone are relatively porous materials. This means that liquids can penetrate the surface of the stone for deep-set stains and even more severe etching. That's why your stone received a sealing treatment when it was installed. These sealing compounds form a protective layer over the surface and close off those microscopic gaps in the stone. That seal isn't permanent, however. It can be damaged by acidic (low pH) and alkaline (high pH) chemicals as well as just general wear and tear from daily use. The general recommendation is to seal your stone every 6-12 months, but this greatly depends on the kind of use it sees in any given area - including after any in-depth cleaning or scrubbing.
How do you know when it's time to reseal?
You can check the integrity of your seal at any time with the water test. This is done by pouring a small spot of water (about 3 inches in diameter) onto the surface of your stone in various locations and letting it sit for 30 minutes before wiping away. If a dark spot becomes visible in those locations, water is penetrating the surface of your stone and needs to be resealed. You can see our sealing guide for more information here.
Alkaline or Basic (High PH) Chemicals Can Be Damaging as Well
While diluted mixtures of bleach can be a great solution for getting out difficult stains in your stone, it should be used sparingly and carefully. In high concentrations or when used too often, bleach or cleaners with ammonia (such as Windex) can dull or discolor the surface of your granite or marble - especially in darker shades. 
If you need to use bleach to remove a stain, we recommend a 50:50 dilution with water and scrubbing with a stone-safe, non-abrasive cleaning pad. Let the mixture sit for 15 minutes, and then rise away with water. Always be sure to seal the stone in these areas after a deep cleaning. NOTE: Never mix bleach with hydrogen peroxide or any other chemicals.