I birthed my cake. There was a uncolonized spot the size of a quarter. Should I not have birthed it. Is it ok to birth a cake even though the whole thing isn't white.
scrape off the uncolonized parts immediatly!!!!
You want 100% colonization...
I like mine to be 100% if it's not it could cause the fruiting process to be slower. IMO
I've done it both ways. "washing" away the uncolonized substrate before or after dunking AND putting cakes in the FC when only 90% or so colonized. The uncolonized portion was small and I put it at the bottom, so it wasn't too exposed. The cakes did fine either way.
If your having trouble getting that last little bit to colonize, a couple things I've found to be helpful: one is making sure the cakes are in the dark, and if the bottom of the jar is not colonizing turn the jar upside down and tap it, then let it sit upside down for a couple of days. Both of those were suggestions I picked here on the forum.