Sealing Granite Countertops Matters – Here’s Why

Sealing Granite Countertops Matters – Here’s Why

There’s a big debate on whether or not sealing granite is important. Some will say that granite doesn’t need to be sealed, especially if it’s a darker colored slab. Some will say that the manufacture will often pre-seal a slab, so there’s nothing that needs to be immediately taken care of. Then again, there are those who say that sealing needs to take place once a year.

So, who’s right? The fact is, for the most part, sealing is important. Even if you’ve purchased a pre-sealed slab, you’ll probably need to re-seal every few years. Below are related issues you should keep in mind



Etching takes place when an acidic or harsh liquid corrodes through the surface of your granite. You can tell if your granite surface has been etched if you notice a spot that looks dull, or uneven in appearance. Natural substances that cause corrosion include lemon juice, coffee, wine, and vinegar. Chemicals such as bleach, peroxide, ammonia and others are also notorious for ruining granite countertops.

Sealing your granite countertops won’t always prevent your counters from etching, but the sealant often slows down the process. Especially after you install granite in your kitchen, you’ll need to be mindful of preparing food and beverages on the surface. But, even if you rest a drinking glass or your coffee mug on the counter, you might still run into problems. If you’re concerned, use a coaster, especially on light-colored granite slabs.


Generally speaking, porosity refers to an object’s ability to absorb water, or other forms of moisture. When an object is of high porosity, it absorbs a high amount of fluid. When you’re select granite countertops, you’ll need to make sure that you select a slab that of very low porosity. As a matter of fact, if you can find a slab that shows little to no signs of porosity, you’ve got a winner on your hands.

There’s an easy way that you can test a slab’s porosity: It’s called the lemon juice, oil, and water test in the industry. You’d simply drop some lemon juice and oil on top of a sample.

If you notice that the spot turns dark almost immediately, you’ve found a high porosity slab. If the spot turns dark after around 10-15 minutes, you’ve got a slab with medium porosity. But, if after a half hour your test slab isn’t showing signs of absorbing the liquid, you’ve got a very low porosity slab on your hands.

Now, here’s a tip to keep in mind: A very low porosity slab won’t absorb a sealant. If you apply sealant to a low porosity slab, the sealant will simply sit on top of the slab, creating a dull finish. On the other hand, higher porosity slabs will absorb the sealant. But keep in mind that a high porosity slab will still absorb certain types of fluids, and this could cause staining. However, a sealant will slow down the process.


As was mentioned, staining occur on granite countertops, and it often takes place on granite countertops in the kitchen. You won’t be able to help it: Everyone drops and dribbles liquid on counters. You’ll also find that oils from the food you cook, even as you prepare the food, might stain your counters. Again, the amount of damage that occurs from staining will depend upon the porosity of your slab. And, as mentioned before, a good sealant will slow down the process of staining.

White And Lighter Hues Will Show Imperfections

Another thing to keep in mind: Lighter hued slabs such as white, cream, light beige and gray will show staining more prominently than darker hued slabs of granite. This is especially true of stains such as coffee, tea, wine, dark liquids, dark fruit juices, etc.

Certain types of oil stains might show as well. The good news is, etching marks will barely show, because lighter colored slabs doesn’t reflect light off its surface very well. This means that you won’t be able to notice its sheen so much, and you won’t be able to notice etching damage.

Darker Slabs And Jewel Toned Slabs Hide Stains Better

Dark and heavy slab hues such as brown, black, charcoal, along with jewel tones such as green, blue and red will do a great job at hiding any staining that takes place. But again, when you seal the slabs, you’ll create a barrier that prevents staining from happening in the first place.

Do keep in mind that etching will be more noticeable on the darker slabs. This is because light reflects brightly off of darker colors, and the polish will gleam in the light. Also keep in mind that your sealant won’t restore the sheen, per se. So, you’ll need to take special precautions to make sure that you protect your darker slab counters whenever you use your kitchen.