I can only speak to wineries but ice cream producers have labs too. The job really depends on the winery size. Small wineries pay the least but usually fairly lax working conditions that allow you to do things other than in the lab. Large wineries have large labs and bureaucracies, which means that you are payed well but micro-managed to death.
I've worked the harvest for the last five years. That's 4-5 months of work (two of which are overtime intensive). In Jan. I draw my unemployment and do some substitute teaching (secondary physical science credential). Otherwise I plan the garden and do a lot of cooking. I'm sure once I get too comfortable a permanent job will come along.