Olive oil on cutting board
I have an ozark west walnut end grain cutting board. For the past year and a half That I've had it I've put olive oil on it about 8 times. I never thought about it going rancid and it hasn't yet, but is there anything I can do to get it out? I'm thinking if I start putting mineral oil on it now, it will seal the olive oil in. Any ideas?
My opinion. It is fine. There are many schools of thought on this. Yes, olive oil will go rancid, but if you are constantly using and washing your board, the olive oil should not stay in long enough to go rancid, especially a home board.
You can just put mineral oil in now if you like and they will mix up and more mineral oil will go in and more olive oil will come out. I don't think putting mineral oil in will seal the olive oil in.
*Edit* Don't get me wrong. I would have used mineral oil instead, but I am saying it is not the end of the world to use olive oil. As long as it has not gone rancid, you are fine.
Rileybuddy, there is some sloppiness in the definition of "rancid," but the physical process is known: through oxidation, peroxides are formed, which then, through further chemical action, become certain kinds of aldehydes, ketones, and other chemicals. When the olive oil is "inside" the cutting board, the paths that oxygen might take to get to the oil are severely limited. Thus peroxides do not form, and the chemicals that signal rancidity do not have their component starting points.
Bottom line: you are just fine. Don't sweat the small stuff.
Actually you'd probably be better off if the mineral oil did seal the olive oil inside. I don't know how far olive oil will penatrate the end graid, but if you've only oiled it 8 times it may not have penatrated very deeply. I'd wash it down with Dawn soap to cut any oil that's within reach, dry it very well as soon as you rinse it off, and then let it air dry really well, preferably with some air movement. Then start a process of oiling it with mineral oil. You can heat the mineral oil slightly to imporve penatration, you can also add a little melted parifin to get a better seal on the wood. For end grain, I would oil it every day for about a week and then every week for a month. Then you can go back to every couple of months depending on how much you use it.
For those who haven't oiled a cutting board, the oil does a number of things, one, it keeps the wood from drying out and cracking and warping. The wood is dried to about 7% moisture before it's turned into cutting boards, but in a hot environment it can dry out even more, treating it with mineral oil keeps the wood fibers from drying out. Two, it keeps the board from staining easily. Also if the pores of the wood are full of mineral oil, they're not going to fill up with other stuff that could turn rancid or worse.