Date: October 26, 2009 @ 9:18 AM

Pumping Over

It is pump-over season in Napa Valley. Our visitors think of it as harvest, and we are finishing up the Cabernet harvest this week, but all these red grapes take quite a bit of time and work to become wine.

What’s a pump-over? It is the act of taking the juice from the bottom of the tank and pumping it over the grape skins that have floated up in the tank to create a cap. A pump-over can look a bit odd in a manner that would likely fascinate Rube Goldberg.

The very character and quality of the resulting wine is deeply affected by how we handle the pump-over.  We vary it due to: the stage of the fermentation from early to late, how often we pump-over each day, how long we pump-over each time, how fast the pump runs, what temperatures result in the juice and the cap. There are a lot of variables.

We start pump-overs as soon as the grapes are in the tank. While it is still juice, a pump-over is fairly infrequent but it is important for starting to extract color before the fermentation gets under way. Every tank of red will receive anywhere from one to eight pump-overs per day until it is through fermentation and on its way to the press. Since a pump-over can last up to 45 minutes, (that is a long one) a winery needs to have a lot of pumps. No matter how many pumps we add, there never seem to be enough pumps at harvest. (We are into pumps and always prefer using a Waukesha.) Understand that a tank with seven tons of grapes in it may see well over 500 minutes of pump-over activity.

There are a lot of moving parts in a winery while the pump-overs are going and going and going. The good news is we get to see, smell and taste the differences that occur from the fermentation and how we handle it. We get to enjoy the magical smell that permeates a winery at this time of year. We know that in a couple of weeks the pump-overs will be over!

It used to be that we parked an intern (me at Phelps 30 years ago - 1979) on top of a tank and the intern sent the stream of wine into the cap like a fire hose. (After a while, some of us would use the stream of wine like a kid with a sparkler…make designs…write our names…etc. Now a days, the wine is gently and evenly spread over the cap by an irrigator. While some of the tanks have automated pump-over equipment, someone gets on top of each tank to be sure that it is all working properly.

Once the pump-overs are done, we can clean up and get some sleep.