I did end up pressing the malbec on Sunday, 6/1. One of the Brutes had fermented dry by Friday night, so I covered with Saran Wrap and got an extra day of extended maceration while I was waiting for free time. Very easy pressing once I got going. Having sat unused for 18 months and moved from Michigan to Massachusetts, my press required a bit of scrubbing to get the cobwebs off. I ended up filling 3 6-gal and 1 5-gal carboys, as well as a 750-ml and 375-ml bottles, which sat for 24 hrs to settle the gross lees. I then racked off the gross lees into 3 6-gal carboys, 2 1-gal jugs, a 1/2-gal jug, and a 375-mL bottle. I hydrated a packet of Enoferm-beta malo-lactic bacteria and dispensed amongst the 'boys to initiate malo-lactic fermentation. And that's pretty much were things sit. The ML fermentation is going strongly, although my chromatography test still shows significant malic acid present after 1 week.
Why the ML fermentation, you ask? Well, this is commonly done on red wines to help soften the acid profile and give a little more roundness. Lactic acid has a low pKa than malic acid, so it reduces the acidic taste. Lactic acid is perhaps most famous for giving that round, buttery taste to California chardonnay, but it does the same thing in red wines. If you don't purposefully initiate MLF, you run the risk of having it start on its own by naturally occurring ML bacteria after you've bottled it. That can lead to exploding bottles due to the CO2 released, and the native ML bacterial strain may give off-flavors that you don't like.
a Wine Student
Prior Chilean Malbec 2008 posts:
Chilean Malbec Grape Crush
Malbec Fermentation Has Commenced!
Malbec Mid-fermentation Update