Finishing Butcher-Block Tops
Pros discuss paraffin, tung oil, and other finishes for a butcher-block food preparation surface. March 2, 2006
We made a large butcher block top for a kitchen out of hard maple. We finished it with 3 coats of salad bowl finish. The homeowner left a wet sponge on the countertop and it discolored the top. Any suggestions for repair and is there a different finish that won't stain from water?
From contributor A:
A real butcher block thatís being used as such can only have a mineral oil or salad bowl finish. It will stain if it isn't cleaned and maintained. A good sharp scraper, sandpaper, and maybe a light bleach solution may work, or if they do not really use it then cover it with spar as a finish.
From contributor B:
Explain to them that is a piece of wood. Water will stain wood. Common sense is what is needed here. If they want to cut meat and vegetables on it you must use the mineral/salad oil on the wood. If it is a show piece and they will never use it for food contact then slap some CV on it. Sure it looked great when you finished it and installed it brand new, but butcher blocks will stain over time from everyday use, itís a given. After so many cleanings with bleach and water it will have to be resealed with the oil on a regular basis.
From contributor C:
Check with Sherwin Williams Product Finishing and ask for a polyurethane clear that is used for laboratory tops and/or hospitals. It has more solids and much better stain resistance than CV. The more solids a clear has the more it resists H2O penetration and chemical staining.
From contributor D:
If the stain is dark - gray or black - you can get rid of it with oxalic acid bleach. Sometimes iron in the water or sponge will react with tannic acid in the wood to leave a dark iron oxide stain. Oxalic is the only remedy I've found to work well. Mix a saturated solution in hot distilled water and bleach the whole top. Use rubber gloves and eye protection and don't try to sand it without first neutralizing it. You can neutralize the board after it dries with some baking soda water or a small amount of household ammonia in water. Rinse again with water. Be careful - this stuff is capable of causing severe skin and respiratory problems.
As far as a finish is concerned, it isn't clear if it's a whole counter top or just a cutting board on the counter. If it's a counter top you've already received good advice. If it is a cutting board to be used for food prep, the best treatment I've found is to melt paraffin wax into the surface. I grate paraffin over the surface and iron it in with a hot iron. Scrape off any excess with a cabinet scraper. The board will feel silky smooth, is absolutely food safe, and is virtually waterproof. Salad bowl finish is just another oxidizing oil finish that might look great on salad bowls but doesn't do much for a cutting board and the same is true of butcher block oil.
From contributor E:
I'm no expert on this but if the wood has already been oiled, is any finish going to stick?
From contributor F:
Tell them to get a cutting board for their cutting. Paraffin wax is better protection than using mineral oil or a salad bowl finish, which is actually pure Tung Oil without any solvent.