granite sealer does NOT make the granite waterproof such that it won't adsorb water. It should retard the adsorption of liquids such that you have ample time to clean up spills without staining the granite.

normally a stain is the result of leaving a staining agent like oil or wine on the stone for an extended period (like overnight)

I once left a soft side cooler full of ice on my counter overnight. it leaked and left a big dark wet spot. in a couple of days it dried out and dark spot was gone. the sealer did not make the stone waterproof.

however, a good sealer like 511 or DuPont StoneTech should prevent instant stains like you described.

I have a light colored granite too, called Bianco Montanha. The test piece without sealer stained easily; with one coat it still stained considerably. It seems as if one application of sealer isn't enough. I have been resealing about once a month since July! I wonder what the experts would think of that? When is it enough and when too much? I am tempted to leave a few drops of red wine and oil on overnight in an out of the way area, to see what happens. With one coat of sealer, the granite had a bright pink stain when I did that. Last week a few drops of cherry juice were spilled and it went unnoticed for a few hours and there was no stain, it cleaned up immediately. So maybe multiple coats of sealer is the key, I would also like to know.

some stones are porous enough to require more than one application. a good fabricator will use the sealer engineered for more porous stones (like "Porous Plus"). It is much more expensive.

you really can't seal the granite too much. once you notice a lot of residue after apply sealer you're done.

Thanks so much for the responses.

Greetings!

We went with daltile Proadvanced Protection Program on our granite. Needless to say, it is a bit of a sticker shock for the program. However, I read way too much about the cheap stuff on the market. We have had our granite for just about a half a year, and am very pleased so far.

I Googled it, and there is a thread on GW, with a representative who underwrites the warranty program replying in the thread.

So far, no regrets.

White granites are generally very porous.
They can be a problem to seal.
Some even consider some granites like kasmir white technically impossible to seal. In some cases that may be true. There are some basic guidelines for sealing a stone surface. Do the water test-puddle up a couple of palm sized puddles of water and let them sit for 10-15 minutes. Then wipe away the excess and see if it has left a darker mark. If it has you know your surface is absorbant.
If it is really porous and most of the water was absorbed you know you have a sponge for a countertop. Really- not the end of the world but thats why the best stone adventures start and end well with an experienced fabricator. One who knows stone and can guide and educate the consumer. So if you do have a porous countertop you should be educated before attemting to seal it or hiring someone to seal it.
Here is what sealing is all about.
Know how porous or not your surface is.
Use a quality product.Impregnator sealers for stone is the product you want solvent or water based. Yes there is a difference but thats another conversation.
Apply(use paper towel) it in manegable sections and let it load on the stone for 5-15 minutes keeping it wet add more sealer if it absorbs into the stone.
Dont let the sealer ever dry on the surface.
Then remove any excess sealer from the surface.
Yes thats right take any excess off. Then overlap the areas you just did and repeat the process until the entire surface has been sealed.
On very absorbant surfaces the stone will get darker -in some cases lots darker. Dont worry thats temporary and once the carrier evaporates it will return back to its normal color and shade.
Always test a spare piece however just to be safe.
If you have a really porous surface repeat the entire application making sure to never let any excess sealer dry on the surface.
So even if your stone isnt that porous or has been resined at the point of processing(resining-another conversation)
You can still apply a sealer if it makes you feel better.
Just be sure to use a small amount and wipe away any excess before it dries. Just take into account if you really need to impact the enviroment and if you really need to seal.
Impregnators live below the surface.
So no matter how many coats you have applied in one day to me it is still one application. You need to understand the sealer needs to cure which takes a minimum of 24 hours.
So let it do its thing and then in 24 hours do the water test again. You will see that it is less absorbant then your first test. If the water beads up and doesnt absorb your done. If it is still absorbing repeat the process and test 24 hours later.
Repeat if needed.
Just remember no sealer will ever be 100 percent bulletproof so try to clean spills up as soon as possible. The definition of a sealer is this.
Sealers temporarily inhibit the intrusion of staining agents from entering the stone. Sealers are getting better and protecting longer as the chemists develop better product. There are some products on the market now to protect marble from etching. Yes they have their pros and cons for sure.
They are worth looking into however as they arent for everyone.
srosen