Here is the much anticipated second posting on granite. This is a post about taking care of natural stone countertops. A complex topic for sure.
There is no doubt that the ordinary task of cleaning one’s countertops can gain a spiritual element when the countertop is made of naturally beautiful granite (or granodiorite, or gneiss, or whatever you have.) And, really, my approach to cleaning is pretty Zen, too.
To illustrate: here are some zen rocks: pretty.
And here is a messy kitchen, the result of zen cleaning. Not pretty.
Actually, this is my mother’s kitchen. And she is going to kill me because my kitchen is usually way messier than hers (which is quite clean). I just don’t take pictures of my mess.
The problem here is that my zen cleaning approach may not be compatible with having a stone countertop. Words like oil stains, etching and sealing fly across the internets warning about how hard granite countertops are to maintain in that House Beautiful, close-up ready way. The reason, of course, is the chemical and physical properties of stones.
More after the jump….
Etching most commonly results from chemical reactions between acidic substances and calcium in stones and results in dull or discolored spots. This most frequently is an issue with calcite and dolomite rich stones like marble and limestone. Granites (in the commercial sense) may also etch if exposed to certain acids and depending on their composition.
The granite gurus (which is an excellent store/blog based in Utah. Utah you are lucky. You also have the awesome grassroots modern.) has some great and very rational posts showing how various substances etch or stain marble.
Staining occurs because all stones are porous. Varying porosity and permiability, which is the connectivity of pore spaces, may determine the extent to which liquids absorb into a stone and stain it. This is a good site to learn all about it http://www.stonecaretechniques.com/. A general rule of thumb is that darker granites are often denser and less absorptive. This is not a guarantee, however. Many stones now a days are resined. The resin is applied to the surface of a cut slab to fill in pits, holes and other heterogeneities in the stone’s surface. A side effect is that the stone becomes less absorptive. You can often tell a resined stone by the drips of resin on the sides of the slab. Again, this is not a guarantee that the stone won’t stain. The only way to be sure is to test your slab!
Like the marble test, there are some tests to conduct to see how susceptible your granite is to staining. The most common are the lemon juice and water tests. See here: http://www.countertopspecialty.com/sealing-granite-countertops.html. The tests are pretty much what you’d expect. Drop some liquid, wait, and observe. Very scientific. Here’s an example of what the water looks like before and after it absorbs into a stone.
I’m not sure how accurate the timings are in that post. But I tested my stone (which is resined) and it took forever for the water to darken. Yes, I know that is a very precise measurement of time.
The final step in keeping granites from staining is the standard practice of applying a sealer. Sealer won’t prevent absorption but it will slow it down signficantly, allowing for lazy spill wipe up. Some granites are so dense they don’t require sealing, and some stones will require sealer every six months. The water test can help to determine when it’s time to seal the granite again. The average is 1-2 years.
Oh, how will I ever do this?? Turns out that you just wipe the sealer on, and wipe the sealer off, Ralph Macchio.
That’s pretty zen. I think I can handle it.