Sealing: who needs it, how often, and the twenty-minute test that decides

Two things are true at once and they cause most of the confusion. Sealing a natural stone counter is genuinely worth doing. Sealing an engineered quartz counter is genuinely a mistake. The advice you get depends entirely on which one is in your kitchen, and a surprising number of people are given the wrong one by somebody selling sealer.

The test, first, because it answers everything

Pour a few drops of water on the busiest part of the counter — next to the sink, or wherever you prep. Wait fifteen to twenty minutes. Come back.

If the water is still sitting in beads, the sealer is working and you are done. If it has soaked in and darkened the stone, it is time to reseal. That is the whole test, it costs nothing, and it beats every calendar rule because porosity varies enormously between stones — some dense granites go years, some open ones want it annually.

Do it quarterly. It takes twenty minutes of elapsed time and about eight seconds of attention.

Quartz: do not seal it, ever

Engineered quartz is roughly 90% ground quartz mineral in a polymer resin. The resin makes it non-porous. There is nothing for a penetrating sealer to penetrate, so it sits on the surface, wears unevenly, and leaves the gloss dull or streaky in the traffic areas.

Sealer residue on quartz often needs professional stripping to remove, which is a genuinely annoying way to spend money on a problem you created. If somebody offers you an annual quartz sealing service, politely decline.

What quartz does need instead: a trivet habit. The resin scorches around 300°F and manufacturers exclude heat damage from warranty, so pots off the burner, slow cookers and air fryers all go on a trivet. That is the entire maintenance program.

Granite: yearly-ish, but let the stone decide

Granite is porous, and how porous depends on the stone. Light, open colors want resealing roughly once a year in a kitchen; dense dark ones can go much longer.

When the water test fails: clean the counter, let it dry completely, apply a penetrating (impregnating) stone sealer labeled safe for food-prep surfaces, and buff the excess off before it hazes. Skip topical "shine" products that build a film — they wear in patches and look worse than doing nothing.

And understand what you bought. A sealer makes stone stain-resistant, not stain-proof. It buys you time to wipe up the olive oil, not immunity from it.

Quartzite: once or twice a year, and verify what you own

True quartzite is harder than granite and does not etch under ordinary kitchen acids, but it is still a porous natural stone. Most kitchen quartzite wants resealing once or twice a year depending on the slab.

The bigger issue with quartzite is upstream of sealing: a meaningful share of what sells under the quartzite label — including some stones marketed as "super white" — is dolomitic marble. It etches like marble and behaves nothing like the quartzite you researched. The lemon test settles it: juice on a sample for fifteen minutes. No mark, real quartzite. Dull spot, it is in the marble family and should be priced and cared for as marble. We will run that test in front of you.

Marble: every three to six months, and sealing is not the point

Marble is more porous than granite, so run the test every few months and expect to reseal every three to six on a working kitchen counter.

But here is the part people are not told at the showroom: an impregnating sealer slows stains — oil and wine soaking in — and does absolutely nothing about etching. Etching is a chemical reaction: lemon, vinegar, tomato, wine and fizzy drinks dissolve the surface of a calcium-carbonate stone on contact. It is a burn, not a stain, and no sealer on earth prevents it.

If you want marble, want it with that knowledge. A honed finish hides light etching far better than a polished one, and many owners come to like the patina. The ones who are unhappy are the ones who were told a sealer would handle it.

What to use, and what to keep away from it

For everyday cleaning on any natural stone: a pH-neutral stone cleaner, stone soap, or a drop of mild dish soap in warm water. Rinse and dry.

Keep away from all of it: vinegar, lemon, ammonia, bleach left to sit, bathroom and grout cleaners, scouring powders and creams. Many "natural" citrus and vinegar cleaners are the worst offenders because people assume gentle means safe — one pass with a vinegar cleaner can dull an entire polished counter.

On quartz, the list is different: avoid abrasive powders, colored scouring pads (the red and green ones contain aluminum oxide — literally sandpaper), steel wool, and anything containing hydrofluoric acid or methylene chloride. Oven cleaner and paint stripper permanently discolor the resin and it is not warranty-covered.

The one repair worth knowing

A dark oil mark in granite is in the stone, not on it, so scrubbing does nothing but damage the polish. The fix is a poultice: baking soda and water mixed to a peanut-butter consistency, spread half an inch thick over the stain, covered with plastic wrap taped at the edges, left 24 hours. It draws the oil out as it dries. Repeat if needed, then reseal that area.

It works, it costs about a dollar, and it is the single most useful thing in this post.

None of this is why you should hire us — it is what you should know whoever installs your counter. But if you would like the whole thing done by the people who cut it, the quote is free and comes with the tape measure: (630) 403-6095.