Food-Safe Sealer for Granite Countertops

QUESTION:

I just bought some granite countertops, installed by someone who didn't know how to clean them or seal them so they are food safe. How do I do this?

ANSWER:

Choosing a food-safe granite sealer is certainly important and a common concern. Most don't know which to use or how to go about sealing granite countertops safely.

The short answer is that nearly all impregnating stone sealers are food-safe and approved for use on food-prep surfaces.

But let's back up a step first...

Often sealing granite countertops isn't necessary. Some granite is too dense, won't stain, and just doesn't need a sealer especially blues, blacks, and greens.

So first, you should water test your granite countertops to determine if a granite sealer is even needed.

If testing shows sealing the granite would be beneficial, then I recommend using one of these impregnating marble & granite sealers.

Sealers become inert after curing. It takes a few days after application for a sealer to fully cure, but once it does the sealer is chemically un-reactive and will not contaminate, react with, or affect your food.

In fact, impregnating stone sealers absorb into the stone and work just below the surface of the kitchen countertop to prevent deep absorption of liquids, so food won't even come in direct contact with the stone sealer.

Learn how to apply a granite sealer properly, give it a day or two to cure before using extensively, and you're good to go!

Keep reading below for additional Q & A information on on food-safe granite sealers, natural and green sealers, and sealing other stone surfaces safely.

Food-Safe Sealer for Slate Countertops

QUESTION:

What food-safe sealer can I use for a slate countertop? It is machine honed (like a smooth new chalkboard) dark gray in color. it is quarried in Slatington, PA

ANSWER:

Most impregnating slate, marble, stone, and granite sealers are "food safe". Stone sealers are made for application to kitchen countertops and food-prep surfaces.

If the slate or granite sealers were not food safe, they would not be approved for use on such surfaces and could not be marketed as such.

Now, of course the sealer itself is not safe to consume, but after it has been applied all the chemicals evaporate and the remaining "cured" sealer is inert... meaning it is not chemically reactive and therefore not a contaminate and safe for food prep areas.

We recommend using one of these marble & granite sealers, which we've found are the most durable and effective.

The above recommended sealers are food-safe and work equally well on slate tile or countertops and on any natural stone or porous surface.

Sealing Food Prep Areas on Marble Countertops

QUESTION:

I'm just starting out making chocolates and need to work with the melted chocolate directly on a marble countertop (or slab) to temper it.

I'm concerned about the chemicals in the sealants getting into the chocolate. I don't really care about the look of the marble.

Can I just leave it unsealed and disinfect it in some way to inhibit bacteria growth?

ANSWER:

Impregnating stone sealers do not contaminate food prep surfaces and will not "get into" the chocolate.

First, when a sealer is applied it absorbs into the stone below the surface with all excess and residue wiped clean off the surface itself.

Second once the sealer dries and cures it becomes inert and has no chemical reaction... meaning it does not/cannot interact or contaminate food.

The only reason to apply a sealer is to help prevent staining. So, if you don't care what the marble countertop looks like, then there is no reason to apply a sealer.

Even though most stains can be rather easily removed from the stone, it becomes a pain if you have to do it over and over like you would on a kitchen countertop.

So, no need to seal the marble countertop if you don't care about stains.

Marble doesn't harbor bacteria or promote the growth of bacteria. Cleanability studies of granite & marble have demonstrated that.

Regular cleaning with a good Granite Countertop & Marble Cleaning spray will keep your countertop as clean and safe as possible.

Or you could use a marble-safe Mold & Mildew Remover, which acts more specifically like a disinfectant.

Sealing Granite Naturally

QUESTION:

I need to seal dark granite countertops, but I'd like to apply a more natural sealer without harsh chemicals (more earth-friendly and not as damaging to people).

The kind I found at Lowe's suggests you leave the windows open for 2 days after applying the sealer. Is there a product that does this more naturally? All I can find is natural cleaners, but not natural sealers.

ANSWER:

I completely understand what you mean. Many sealers are solvent-based and very noxious during the application process.

Note that once a sealer is applied to the countertop or floor tile and dries it becomes inert and non-toxic.

It's only during the application process when you are directly exposed to the liquid and fumes that a sealer may have an impact on human health.

Recently water-based sealers have been developed to try and minimize the impact on humans and the environment.

Now I wouldn't necessarily call these green sealers, but much better.

I recommend using these recommended marble & granite sealers.

Now, you say you "need" to seal dark granite kitchen countertops...

Have you performed the water test for sealing granite to be sure that it really does need sealing... or did someone just tell you to do it?

Some granite varieties don't need sealing... mainly a few darker varieties. If you test the granite and the results demonstrate that it doesn't need sealing then you should NOT do it "just to be safe."

The sealer must get below the surface into the pores of the stone. If the stone is really dense, the sealer will just sit on top and the residue will leave a streaky mess even after you wipe off the excess. You'll then have to strip off the sealer, and believe me, you do not want to do that job.

If the granite shows signs of even a little porosity/absorbency, then go ahead and seal it.

Non-Toxic Natural Granite Sealer

QUESTION:

I purchase a light-colored granite countertop and I would like to use a non-toxic natural sealer. What is available?

ANSWER:

As for natural sealers you could use linseed oil. It was one of the original types of sealers, but it won't last long and will turn yellow with age.

For non-toxic sealers these recommended marble & granite sealers are as good as your are going to get.

Stone sealers will have some fumes during application, but they are not toxic after cured on the countertop.

So, if you are worried about exposure to food... it's not an issue. The reaction that occurs when applying a sealer and after it dries leaves behind molecules that are inert and do not contaminate food.

Most light-colored granites need sealing to guard against stains, but you can simply water test it to find out for sure if you need to seal.

Sometimes you don't have to. If you do... use the recommended marble / granite sealers for the best results and stain-protection.

What Non-Teflon Based Sealers Are Available For Safe and Effective Use On Granite?

QUESTION:

I have a new travertine floor, granite countertop, and backsplash. I am looking for an environmentally safe non-teflon (fluoropolymer) sealer. Do they exist and what are their names. Thanks, Dr. Smith

ANSWER:

Flouoro-carbon sealers are pretty standard these days, however, water-based granite sealers like Impregnating Stone Sealer (the water-based sealer we recommend) are less toxic (lower concentration of volatile organic compounds) than solvent-based sealers.

Sealers labeled "non-toxic" may not be actually non-toxic for the environment. Some sealers are marketed as "non-toxic" or "no VOCs" but EPA rules actually target certain VOCs over others, thus a company can claim a product is "zero" VOC and still contain up to 5%.

Or "Green" labels do not necessarily mean that the chemical is completely non-toxic and non-harmful.... just better than the others.

Not being a chemist, I can't definitively answer this question beyond the above explanation. The granite sealer game is won on durability, so the effort is to engineer sealers that protect against all types of oil and water-based stains and last as long as possible.

So far, this entails using chemical compounds that have some toxicity.

However, it is important to clarify and understand that a granite sealer prior to application is toxic, but after applied and cured the VOCs evaporate and the remaining compound is inert, non-toxic, and safe for food prep, etc.

So when talking about "safety" of granite sealers we are not deciding which is safe to use on a countertop. They are all designed to be used on food prep areas.

The issue is that some are less environmentally toxic upon application, so the less-toxic sealers will release fewer VOCs into your home. And this occurs over a short time frame of only a few days to a couple weeks.

Of course, your home is already made with all kinds of materials that emit toxic fumes, which people have developed sensitivities to (sometimes severe).

You could go back in time and use the original sealer... linseed oil, but that would require constant re-application and it tends to yellow.

Also, consider that you do not "have to" seal all stone. By performing a simple test for sealing granite countertops you can determine if your stone even warrants application of a granite sealer.

Many stones are naturally very dense, stain-resistant and should not be sealed.

Also, it's helpful to remember or learn that most stains in stone can be easily removed. It's just that if you have a porous stone for a kitchen countertop, then removing stains can become a nuisance, so sealing makes sense.

But for installations that have a low risk of staining, sealing is very optional and in many cases just unnecessary. This includes some floors, showers, lightly-used bathrooms, or even kitchen backsplashes which get surface splatters, but rarely stains.

Granite Sealer Chemical Odor Sensitivity

QUESTION:

I am hypersensitive to chemical odors and I would dearly love to have a granite countertop. What are the sealers made of? Do they off -gas and for how long?

ANSWER:

Nearly all chemicals have an odor and some are going to bother people more than others.

Granite sealers are made using either a water base or a solvent base. Solvents are volatile and will off-gas until evaporated at least.

Water-based sealers still have some odor, but not typically as strong as solvent-based sealers.

Usually you will notice an odor only for a couple days or less. However, I'm not a chemist and it is possible that off-gassing occurs with all types of granite sealers or other chemicals longer than your average human would/could actually smell.

So, someone with odor sensitivity may notice it far longer than typical.

The impregnating sealers we recommend represent both water and solvent-based sealers.

There are arguments for both types although many (and in the future possibly all) are going to a water-base since solvent chemicals are more damaging to the environment.

But you don't have to worry about it!

There are plenty of granite colors that don't need a granite sealer because they are dense with low absorption rates.

Such granites are naturally stain resistant and do not need sealing.... in fact couldn't be sealed even if you tried... the granite sealer simply won't absorb and nothing else will either.

These are the most bullet-proof surfaces you can install... highly recommended.

In your situation, I'd choose a dense granite that does not need sealing.

I know you've read that "all" granite "must" be sealed, but that's just marketing mumbo jumbo from quartz countertop and granite sealer manufacturers (trying to sell their product) and from poorly informed stone salespeople, etc.

It's simply not true... many granites and many stone types never need sealing.

That's why you should always perform the water test for sealing granite on a sample taken from the granite slab you are considering purchasing... or when trying to determine if an existing installation needs sealing / re-sealing.

This test will tell you how absorbent a stone is and whether or not it needs sealing or if it even can be sealed.

You should also perform the "Lemon Juice Test" to weed out the rare granite that reacts to acids. Some black granites are appearing in the marketplace now that will etch, so you have to be on the lookout... don't want those.

Most of the granite colors that don't need sealing are on the darker side, but you still have lots to choose from. This is the way to go if you want to avoid applying a granite sealer.