Periodically go from floating to sinking while refrigerated. Sometimes they're all on the bottom of the jar and then a few hours later they're all floating again.
:) The gas bubbles stick to them (inside and out) they defy gravity (if it's still called that) and become lighter than the fluid. The gas bubbles rise transporting the raisins to the top. The bubbles pop on the surface. The now heavier raisin sinks after losing its buoyancy (down to the depths of the earth) getting stopped at the bottom of the glass.
So the raisins movement is indicating gas collection as they rise, loss of that gas as they sink.
I was told that my YW only needs refreshing when all the fruit sinks to the bottom. That's why I was initially confused.
just stay on the bottom and it is high time to change them out for the new floaties:-)
I think before long it'll need a refreshment. It's actually lasted quite a few weeks and there's still activity going on. I am surprised actually. Never kept one for this long before. Surprisingly strong.