Benjamin Moore and Sherwin Williams have industrial coatings for concrete just tell them what you need it for.

You must make sure that the sealer you use is food safe as being a kitchen countertop. Industrial type flooring sealers are a total different product from what should be used on countertops. Did you pour the tops in place? Is this a DIY project or did you hire a pro to install? If this was hired out, the installer should have a sealer they have worked with and are comfortable with the results. If this was a DIY project, the concrete mix manufacturer you used should have a recommendation of what would work best with there product. There are no perfecct sealers, but many that will provide a good level of protection. Be prepared to spend for the best sealers, but you will get what you pay for. The proprietary sealers I use on my projects run from $50-$80 per gallon and I like to apply at least two if not three layers for ultimate protection.

We sealed ours with a concrete sealant product from home depot and we applied several layers. It will say on the back of the container whether or not it is food safe. Then applied beeswax to shine it up a bit and protect it even more. Also found something that makes it really shiny. It was just in a spray bottle and I think it is called Stone Polish. That at home depot as well. The label is green and black but can't remember the name right now. Makes them super slick.. :)
And we haven't put any heat on them, but other than that, just wipe up quickly if you do spill something. I have stainless steel trivets from IKEA that I use for hot pots and cookie sheets out of the oven. One just lives near the oven on the countertop for easy access. FYI, ours are not pristine...but have patinaed and I love them. They have character and are very basic and I wouldn't trade them for the world! Hope you love yours just as much!

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