There are certain FDA approved finishes that can be used to seal butcher block countertops. There are different kinds out there. I would call a local cabinet maker to see what they use and to find out where to get it. You also can use mineral oil, but the finish won't be very glossy. Oils such as peanut oil should not be used because the oil can actually go bad. Mineral oil is all that should ever be used.

Tung oil is another possibility, and builds a somewhat glossy film on the surface whereas mineral oil doesn't. The main attraction of oil finishes, though, is easy repairability. If you won't be cutting on it, then you may want a more durable coating such as a polyurethane or a waterbase acrylic. These are not as easily repairable but they are more resistant to scuffing and moisture penetration than any oil finish will be.

I've linked to a handy bit of information on the subject.

Here is a link that might be useful: Wood Finish Supply / Cutting boards and countertops

I have tung oil finishes on the wood counters in my kitchen. I used 7 layers initially. I have added a couple more in the past 2 years to refresh the finish because I do a lot of breadmaking on the counter. I tested the finish by leaving a small pool of red wine on the counter overnight. In the morning it wiped off with no residual effect.

Tung oil gives that "glossy, warm, amber lustre" you are seeking.

Hi again,
many thanks for all your helpful advice. We ordered the counters last night, so I will soon be testing out your ideas. I particularly like the sound of tung oil, the glossy amber colour without a plastic look. Will it offer enough protection around the sink area though?
L

Laura, Tung oil is the protective finish that Chinese sailors used on their wooded hulls for centuries. It will protect your sink area if you maintain the finish. That means whenever it starts to look worn, you add another coat. In a sink area, I would probably recoat 2-3 times a year. If you are not directly working with food on the counter, I would suggest polymerized tung oil. If you are working with dough, use pure tung oil.

The link below is to Lee Valley, an excellent supplier of quality woodworking and other products. Check out the technical and instruction bulletins with these products. Email Lee Valley if you have additional questions about them.

Here is a link that might be useful: Lee Valley Tung oil

i'm so happy to stumble upon this thread, as we're installing our butcherblock counters next week and i'm a little more than confused regarding our sealing choices....

i just checked the lee valley tung oil website, and am wondering what the differences (pros/cons) are for the three products available: pure tung oil, polymerized tung oil, and polymerized tung oil sealer! AND, what the process is: how many coats, how long between each coat, do you sand? i will not be using my counters for cutting, and want as strong a finish i can get (with the above mentioned "glossy amber color"....).

thanks.

thanks so much!

Pure tung oil is just the extracted oil, like cold-pressed olive oil, walnut oil, etc. It is the most food-safe of the three. But it is fairly thick and a rather slow drying.

The others have additives. The sealer has thinners to make it penetrate the wood more deeply (you just use it for the early coats) and the polymerized is heat-treated (and then thinned) to make it dry faster.

If you will not be cutting on it and not regularly using it to knead dough, I would recommend the polymerized. It drys faster. I don't bother with the sealer, but just thin the first coat with equal parts of mineral spirits. Wipe it on generously, let it sit for about 5-10 minutes then wipe off the excess with a clean, lint free cloth. I wipe it on with my hand and a cloth. Let it dry for 24 hrs, or 48 if you are using pure tung oil. Repeat with undiluted oil, building up the coats and letting it dry until you have at least 6 coats on all sides. You can coat the opposite side while the other one dries.

Don't be tempted to add more until each layer has dried hard and you can't wipe off any with a clean dry cloth. Don't skip the wiping off step. You won't need to sand if you wipe off, as it makes the coats level and even.

i just started using 100% pure tung oil on my countertops after doing 5 treatments of boiled linseed oil. the first time i applied the tung oil, i sanded the counters until satiny smooth, put on the tung oil, wiped the excess off hard, then 15 minutes later wiped off the excess again. one hour later i put on a second coat, wiped, waited, wiped, then went to bed. the next morning, i could pour a glass of water onto the countertops, it sat right on top and did not seem to penetrate at all. my counters have a slight reflection in them, more of a warm glow, and are liek satin-- soo nice to touch. one tip: i put a pot in hte sink, and filled it with hot hot water, put the bottle of tung oil in the pot, let it roll around in there with the water running for ten minutes. it was much easier to spread this way. another thing- make sure you sand all of your counters first, not sand, coat, then sand another countertop while waiting for the first to finish. you'll get sawdust stuck in your still tacky counters- no fun!