What Does Pump Over Mean In Winemaking?

VIDEO TRANSCRIPT:

Here we are at harvest, we're doing pump overs on tanks. So, basically we take the fruit, run it through our destemmer, and put all the berries in here. Now remember, clusters come in looking like this. We take them and the juice is clear. There's no pigment to grape juice. It's clear juice. So, once we take them in here we need to get the red wine. The red color that comes from the skins, so if you look we're pumping the tank over that's been fermenting for a day. We're starting to get some pigment out of that, but if you just let the grapes float on top... you need to mix it… if you don't you just get a rosé colored wine. You don't get the extraction that you're looking for and basically you need to keep that mix going four times a day, for 15 minutes. 

You pump the clear juice off the bottom and mix it over the top. This process is called pump over. This is actually a fire hose pump over. It takes an individual to sit here and do this. You can do it with an irrigator, it's like a sprinkler, but it doesn't work as well. So, one of the reasons we have labor around the winery is for things like this, hand work. 

On a small scale you can do it with a punch down. Just like a plate and push up and down inside the wine and that works pretty well, but in this size tank I could walk on top of it. I can't do that by hand, but this size tank gets appropriate heat from the yeast, so it's you have to balance those two things with what you want. 

This tank is zinfandel. It's actually running at 72 degrees currently which is right. One, I treat zinfandel more like pinot noir than like cabernet. It's kind of a gentle monster. It gets really big and really bold, but if you treat it like cabernet i think it gets too rough around the edges. I like the raspberry. I like the cherry characters it has and that's what this pump over gives them. We roughly are trying to rotate the entire volume of the tank over the top, mix it in. Make it look like soup, but what happens is the yeast produce co2 gas the gas cleans the skins and the cap rises on top of the tank. That cap on this tank is roughly four feet thick, so i can walk over it and those little tiny bubbles will hold me up. Um... hopefully they hold you up. In europe this is actually how they do it. They put pieces of wood under their arms and they walk through the tank and mix it with their legs. OSHA doesn't really like that, so we did not do that here in the United States. We do the pump over method. This is the most common method of mixing wine.

For white wines you would never do this. The oxygen is a problem. The red wines, this oxygen being mixed in during fermentation makes your wines big and round in the mouth instead of being tight. Sometimes we pull off the bottom valve down into a bin so we can oxidate it first and oxygenate it again. If that wine's getting too tight or too hard, so we want to get bigger and bolder that's called the Délestage. We tend to do that in here as well.