Grenache: Separation and Racking

Crushing and pressing 100 pounds of grapes was the first step in making our first "real" wine, a Central Valley Grenache. We left off last time with around seven gallons of grape juice, most of it sitting in the primary fermenter with the grape skins and a few of the stems still in the mix. After adding yeast and waiting a day or two, a "plug" formed, with all the skins rising to the top of the fermenter.

We stirred every few days to degas and ensure that the yeast were evenly mixed through the fermenting juice...

...until the juice was about the color and character we wanted. If we had left the must (the skins, stems, seeds, and other assorted grape parts) remain in contact with the juice for longer, we would have ended up with a darker, "bigger" red wine, with a more dry and tannin-intense flavor. We didn't want to go too strong, so we stopped around here:

 First, being good scientists, we recorded the specific gravity...

...and the pH.

The pH was in the range of 3.5, essentially unchanged from last time, but the specific gravity had dropped all the way to 0.993. That suggested the alcohol content of our wine will be around 13 to 14% by volume once it's ready to drink.

After we made our measurements, it was time to separate the juice from the must. We siphoned most of the juice straight to a glass carboy, leaving the must and some sediment at the bottom of the fermenter. Here I am, clearly excited to siphon.

Unfortunately, this didn't go as smoothly as we wanted. About halfway in, the tubing decided it had enough of our auto-siphoner, and Kierston took the brunt of it.

Once we'd recovered from our mini-disaster, we ran the sediment-laden juice and must through a strainer, reserving the skins. Here's Forrest, pressing the skins one last time to recover some last drops of juice. This was surprisingly effective--we guessed we got a free bottle of wine or two from the second pressing.

Here's the total volume of juice. Notice how incredibly sediment-y it is... this is mostly yeast biomass but also leftover particulate matter from the grapes that was too fine to strain.

 For comparison, here's what our Carnot Cabernet looked like at this stage.

It's much redder--indicating that the finished wine will be darker--but otherwise similarly turbid. You wouldn't want to drink the wine at this stage, but fortunately, gravity started doing its job almost immediately to settle out most of the sediment.

The bottom sediment layer continued to grow for a few weeks; after a few days, the young wine developed this stratification pattern from phase separation.

A week or two later, the separation was nearly complete, and most of the wine was in the clear purple top phase. We racked again to discard the sediment, and replaced the wine into the carboy to wait for the slow secondary fermentation and degas steps.