A nice old guy at the farmers market turns Local wood, wooden bowls and I bought 2 for the wife & one small for my pack. I got a little lost as to which bowl was what wood :redface: Spruce maybe?
Anyway the bowls were unseasoned, I have been coating with food grade mineral oil as if oiling a stock (light coats with ever increasing intervals between). After 4 days I think I have a dozen coats in. Anyone have experience with seasoning wooden bowls? Guess I'm a bit unsure how far to go. It's not as if they were teak, I think I paid $32 for the 3.
I've made a lot of woodenware, and would recommend using flax oil. This is the same thing as linseed oil, but for food it's typically referred to as flax. Walnut oil is also a hardening oil, though anyone with a nut allergy should obviously avoid it.
The USDA approved (just like bisphenol A and a whole host of other "food grade" nasties!) food grade mineral oil isn't a good idea imho, for two reasons. First is that it remains liquid, and thus washes out and/or evaporates relatively quickly. Second is that as a petroleum derivative, I don't trust it. You'll find plenty on-line to scare you from using it if you look around.
I've heard some suggestions that olive oil will also polymerize, but my own experience with it was that it turned rancid smelling before polymerizing, so I don't use it.
The best way to treat with walnut or flax oil (make sure either is sold for food use; boiled linseed (aka flax) oil contains chemical drying agents you don't want in your food!) is to first make sure your bowl is *DRY* -- like sitting next to the wood stove for a month or so. If it's not dry, you risk cracking in the next step. Next, have enough oil on hand to immerse it, at least halfway. Heat some oil up on the stove. It's flammable, and can burn inside the pot, so be gentle with it, and don't leave it unattended. Once the oil is hot enough (above boiling temp), put your bowls in. Bubbles from air and moisture in the wood (even a dry bowl still has some moisture content) will start escaping from the end grain of the wood so long as the oil is hot enough. Eventually they'll stop, and your bowl will likely sink to the bottom. At this point, take your oil off the heat and leave the bowl inside as it cools. This will draw the oil deep into the wood grain. Turn the bowl every so often if it's not completely submerged, to ensure that no surface goes dry and cools without drawing in the oil.
Finally... find a nice sunny window, and let the bowls sit there for a few months. UV light and heat will speed the polymerization of the oil as it hardens. Sitting on a shelf above a woodstove also works pretty well. Once you can rub it with a piece of white paper and not get any oil on it, you're ready for use. This treatment will last far longer than the mineral oil option, though it will still need occasional renewal. My "daily use" bowl starts to show signs of drying after about 1-2 years of use.
You can of course skip the drying period if you're dying to use the bowl before the oil is cured, but you'll get a little oil in your food, and anything hot will cause oil to seep from the pores of the wood. But, unlike mineral oil, flax and walnut oils are actually really good for you!