depends on the porosity of the granite - some granite will accept sealant - others will hardly, if ever, accept sealant. You need to get a sample of the granite you plan to use and test it to see how well or not it will accept liquids.

My granite fabricator only purchases Labs that are pre sealed with a 20-year sealer. She always tells homeowners to treat the stone like you would your car hood. You could use a stone Polish. If used too frequently it can cause buildup on the countertop surface, she had this happen with one homeowner who used the Polish multiple times a day. I would suggest warm soapy water on a pre-sealed stone countertop.

The items you quoted from the article are correct.

From the "Stone Information" FAQ...

Not all stones need sealer. Stones like Blue Pearl, Ubatuba, Black Galaxy, Verde Peacock, Verde Butterfly, Platinum Pearl and many others are too dense to absorb any liquids - sealers included. Sealers only protect stone from staining through absorption, so in stones with low absorption co-efficients, sealing would be superfluous.

Sealing dense stones could lead to nasty results, such as streaking and ghost etching, so DO NOT go by the motto of "seal it anyway, it could not hurt". Rather test your stone for absorption by dripping water on it to see if it darkens any. If the water has no effect on the stone, sealing it is unnecessary.

You shouldn't seal granite with an absorption < 0.25%.

https://ths.gardenweb.com/discussions/2558824/stone-information-and-advice-and-checklists

I felt a little foolish posting this question, but I am so glad I did. These responses have been very helpful - especially that link, Buehl. I had been planning on sealing my granite frequently - just to be on the safe side!

"You shouldn't seal granite with an absorption < 0.25%"

How do I find out the absorption rate of the different granites I am considering? I have also read here that some granites stain so easily they shouldn't even be considered for a kitchen (Kashmir White), and I've read that some are extremely chippy. How do I find out which ones to avoid? I've tried to find some kind of list on the internet, but I was unsuccessful.

I am a fabricator. Previous posts are accurate if incomplete. Many popular granite colors have naturally occurring surface irregularities after polishing. These irregularities are so shallow they can't be felt with a fingertip but are visible when the lighting is at the correct angle. It's not something a person would see typically unless looking for it. To make those colors more commercially acceptable many such colors are treated with a resin prior to polishing that results in a "glassy smooth" polished surface where the surface irregularities are filled by the resin. These colors can often be identified by inspecting the edge of the slabs where traces of the resin can be seen on the raw edge of the slab. such slabs do not require sealing.

I once had a customer that applied an entire bottle of sealer to his recently installed bar top. (The bottle was at least a 10 year supply.) The result was a hazy mess. Fortunately most sealers can be removed relatively easily by an application of acetone. (Acetone is a very volatile liquid so proper ventilation and gloves are required.)