Just checked, and so far, no obvious fermentation. I stirred it up, and brought up a lot of foam, so maybe it is starting. The color is really deepening. These few days of “cold” soak are really drawing out the color.
I tasted the juice; still tastes great.
This morning I’ll leave the garage door open, so the southern sun will be on the bin most of the day. The bin is covered with a sheet, and a piece of plywood. The plywood gets very warm in the sun, which should indirectly heat up the must.