|The garlic was blue, but the ginger looked like...ginger.|
Thumb and finger holding a piece of blue garlic.
As advised, I tested the pH of my nukadoko. A garlic clove and a chunk of ginger went in, and persimmon peels were set to dry soon after.
I checked the garlic and ginger chunks the next day, and there had not been much change. I did find a clove that had turned blue, but I am deeply suspicious it was one that had been loitering there for some time. The ginger, as Elizabeth wrote, looked like...ginger. This could mean the pH was off, which would account for the extreme sourness. Next steps were in order!
Meanwhile, I prepared a hearty skillet of The McFerrin in preparation!