With our counters being delivered in 2 days, it was time to finally nail down what type of finish we're going to use . Ikea sells it's own counter sealing oil (called Behandla), which would seem to be the obvious choice but different counters have different needs, even in the confines of my own small kitchen. The "outer L", where the sink is and most dish drying happens, could benefit from some extra waterproofing. The island, where most cutting and food-prep goes on, could benefit from a coating that penetrates so that even a knife gash in the wood would still be protected.
This article from Ikea Hackers, was INCREDIBLY useful. Basically, it says that there are coating or drying barrier-like options and penetrating or non-drying potions. Most of the barrier options are not food safe, but the one that is is waterlox. It claims to be tung-oil based, but comes in a low-VOC formula (which means that the original formula isn't so low in VOCs). My guess is it's a mix between an oil and a urethane. It is the most water-proof of all the options and it's the one I've chosen for the "outer L". It comes in both Original and Low-VOC, and original, satin and gloss sheens. The original sheen is both a sealer and a finish, the satin and gloss sheens are just finishes, so you have to put a few coats of the original on no matter what. Also, if you use the original sealer, you have to use the original finish. If you use the low-VOC sealer, you have to use a low-VOC finish. This morning, my task is to order a quart of low-VOC original sealer/finish and a quart of low-VOC satin finish.
I chose the satin finish because, when the island piece is in-stock and finally ordered, I plan on coating it with mineral oil. Mineral oil leaves a satin sheen and I'd like for the counters to have similar sheens. All of the penetrating finishes (which you can cut on) are oils. Tung oil, behandla oil, mineral oil, linseed oil. There are ups and downs to each of them, but mineral oil is the least expensive, most easily gotten a hold of, and i know folks who have used it to great effect.