According to a couple of authors (Iverson and Cox) typically you press
at some point when fermentation is slowing down. Then you transfer the
wine to a carboy with an airlock and you allow the fermentation to
continue in the carboy, and you rack off the lees as soon as the
fermentation is finished.

David wrote:
> Hi all,
>
> My Pinot Noir has just completed primary fermentation, been pressed,
> and is now settling out in several carboys. A healthy amount (1-1.5"
> deep) of lees are visible at the bottom of each carboy.
>
> Most of this is gross lees, some of it is yeast.
>
> I haven't pitched in the MLF culture yet, and am waiting until I figure
> out whether I need to rack the wine off the gross lees (to a fresh
> carboy) or not. Lots of information in books, online, and this n.g.,
> which offer advice either way -- would be nice to read a clear opinion
> or two so I could figure out which way I want to go.
>
> Thanks in advance,
>
> David