Q: Why is freshly milled teak blotchy?
A: This is a common question from those who have never worked with teak lumber (tectona grandis) before. It is lighter in color in the center than on the surface. It can be shocking when you run a piece through a planer and all of a sudden there is a lot of contrast and it even looks green in some places. Teak changes fast with an oxidation reaction when exposed to UV rays (ie – the sun) and you will see that within a day of exposure to sunlight, the color contrast typically changes and the teak will even out over time for a more uniform look.
If you want to do a little experiment, take a sample of teak and set it in sunlight, the lay something over the top of the board where it is partially covered. Let it sit for an hour or two, then come back and look at it. You will see the oxidation reaction has already begun to change the surface appearance. So give it time to do its thing, and it will look great in the end.