I'm thinking that a presser made of wood is probably the wrong medium to use for fermenting a crock of sauerkraut. Or maybe I just need to do some further research (instructions? who needs instructions?). I took the weight off the presser, the presser floated up to the top - and within a few scant days, the wood molded. The sauerkraut below may have been okay regardless, and by golly it did smell like good sauerkraut as I was cleaning it out of the crock and throwing it away, but better safe than sorry. Dang it.
I'm hoping the third time's the charm. Thankfully, cabbage isn't too expensive. I've tossed the wood presser, as mold is almost impossible to fully eradicate once it has established a foothold in wood. Next time I'll use a smooth-glazed plate instead. Onwards and upwards!