While it is true that granite is harder than marble which is harder than limestone, slate or soapstone, natural stones are all absorbent and sensitive to acids. You can reduce their susceptibility to absorbing things by sealing them both upon installation and on some regular maintenance schedule, but you cannot eliminate that characteristic completely. Wipe up spills and splatters as they occur with a soft cloth dampened with mild, soapy water. This simple step will lead to a lifetime of happiness.
If a liquid of any type is left on a natural stone surface, it will soak into the stone; it is just a matter of how long it takes. Should you have the situation where something has soaked into the stone and left a stain, you need to reverse the process by putting something on it to suck the stain back out of the stone. Generally, this is done with a “poultice.” A poultice is a mixture of a non-acidic absorbent material like clay, diatomaceous earth or talc that is moistened with a liquid that breaks down the stain that is in the stone and allows the stain to absorb back up into the poultice and out of the stone. The liquid used to moisten the poultice is determined by what caused the stain in the first place; for oils, the poultice requires the use of ammonia, for coffee/tea/foodstuffs, the poultice requires the use of hydrogen peroxide. There is a good reference for what materials to use in your poultice on the site www.natural-stone.com. The poultice mixture is placed over the stain, covered with plastic wrap with a few holes for ventilation and left over the stain for a day or two to work its magic. Sometimes, the process needs to be repeated a few times depending on the tenacity of the stain involved. Once the stain is reabsorbed, the stone can be polished and buffed back to its original luster.