anyone seen this in there oak?

[Johnny B Shiney]

This was toasted first at 2hrs 200 deg, wrapped in about 7 layers of alfoil, came out very very light, so I changed it to 2 layers of foil and toasted again for about 2hrs at 200 deg. Colour is ok but I am wondering if I stuffed something up, looking at those circles.

[rumdidlydum]

Was that the side they were siting on.?
Were they used or new?
It looks like a small amount of moisture has come out of the wood and pooled where the marks are. Then evaporated off :think:

[Johnny B Shiney]

The circles are on both sides so it cant be from how they were sitting, plus some of the bits are curved,so i doubt its from touching other bits etc.
The oak pieces are new from rotb.
I am thinking perhaps not toasted evenly all the way through. Apart from that they are a nice colour and smell good.