I use food grade oil on mine. Available at any hardware store. Lightly sand if necessary, oil, buff, oil, buff. It's an all-day process with wait times, twice a year.

Thank you, so the oil gives them a shine that lasts?

I used Waterlox in my kitchen and a couple of bathrooms that have wood countertops. I used it because it protects the wood from water damage and because it's easy to touch up. I'm unfamiliar with the product in the last photo, but you mentioned polyurethane in your title and I would not use that in an area with water like a bathroom or kitchen because it doesn't offer enough protection from water and because you cannot touch up a small area, you have to sand the entire surface to do any repairs.

Use Waterlox. you want something that is food grade safe on your counters. Poly is not! plus, poly is too rigid and will not move w/the contraction and expansion of wood. it will end up cracking over time. Waterlox or a similar protectant for food grade butcher blocks.

waterlox is basically tungoil and a food safe solvent. also comes in different sheens.

https://waterlox.com/project-help/guide?id=8abadfea-3ef1-446a-8d80-33992c09f550

mineral oil is not enough to protect them from staining and water.

btw, that 2nd pic, thats a resin coating, they're torching it to remove the air bubbles. that's fine if you want a thick, bar top look. not practical for a working kitchen.

Aw, good to know about the poly! Thank you

ETA: Formby's Tung Oil Finish is not Tung Oil

***

We've had bamboo butcher block for about 2.5 years. I'm honestly shocked at how durable it is. My husband went a bit overboard putting ~ 9 coats of tung oil on them and we haven't treated them since install.

that's what's in Waterlox,,,tung oil! it's a natural wood protectant that hardens over time.

If you use Waterlox, apply it when you have a nice stretch of weather where you can leave your windows open. It smells horrendous while it's drying, and you need about twenty four hours between coats. I like to use at least four coats, usually five. It will change the appearance of the wood... I've always used it on walnut and it goes from looking like a cool toned brown wood, to a rich, warm, brown. So you might want to test it. The projects I've done, the wood has been sanded very smooth and silky, so I tend to lightly sand in between coats of Waterlox just to keep it very silky smooth, but it's not needed for adhesion purposes like many other products like paint or poly.

All of the comments have been soooooo helpful! Thank you very much!!!

Yes the tung oil is what I use. I'm not at home and I couldn't remember the proper name :)

benjesbride,,,, that's tung oil finish,,,it's little oil and full of resins and varnish. it's not the same as pure tung oil. sorry. research it for yourself. I think i read somewhere that it's 78% mineral spirits, mixed with very little actual tung oil.

https://sawmillcreek.org/showthread.php?27840-tung-oil-questionIf you want to use tung oil, then use actual 100% tung oil. if it doesn't say that, it's a varnish. And I don't want varnish on my food prep surface.

Waterlox could be the same, although, they do say it's food safe (once dry!)

https://waterlox.com/

Lots of products here you should consider. Don't hide the wood under plastic.

Use multiple coats of 100% tung oil. Let each coat dry before you apply another coat.

https://www.realmilkpaint.com/shop/oils/pure-tung-chinawood/

Beth - Well, that explains why our counters are in such good condition after years of use!

I don't prep on our counters, always using large cutting boards so hopefully Formby's hasn't compromised our health or something.

benjes,,,you have a varnished counter and didn't even know it! I'm sure it's fine. the spirits actually dissipate when dry. it's just that people think they're getting something when they actually are not. marketing ploys!

Just to point out that tung oil shouldn't be used if people with nut allergies are likely to be around, especially tree nut allergies.

Should stain be applied before the tung oil, or just use the tung oil and apply no stain? I know the oil naturally changes the color, my question is, will the protectant from the stain combat the oil?