Lately it’s a high tech term, but really it seems like common sense doesn’t it? In Bordeaux Chateau Lynch-Bages built a tank house that employed a railed gravity flow system in 1850. The lower level held the vats and the upper level was for de-stemming and crushing so that the juice would flow (via gravity) into the vats below.
Gravity flow these days is seemingly expensive with huge complexes built to support this method. The Palmaz Winery in Napa is the ultimate example of this. This is the ultimate in gravity flow winery design. This winery is built in Mount George in Napa. The wine cave is 18 stories tall with fermentation tanks that rotate on a carousel under the crush pad.
Halter Ranch in Paso Robles just finished a beautiful new facility that is designed for gravity flow and ease of work flow for winery workers. On top of that the place is stunning. ( more on Halter Ranch Soon)
Of course there are simpler methods. Take Willakenzie Winery in Yamhill Oregon. This winery is simply built to be 3 stories down the side of a hill. The top floor is for sorting and de-stemming, the middle floor for fermentation and tank storage and the bottom floor for barrel storage. The juice/wine flows from one floor down to the next via gravity.
But even small wineries can make this system work. You just have to have your tanks higher than your barrels! A simple hose from the tank to the barrel will work! You save the expense of the pumping equipment as well as the maintenance and energy costs. This method is a bit more time consuming though.
You can fill a barrel in 4 to 5 hours, but…if you don’t wish the gravity to push too hard on your wine, you might adjust your hose to allow the juice to flow more slowly taking 7 to 8 hours to fill a barrel. So if you are a big mass producing winery you probably don’t want to take the time to do this. But…if you are in the business of making good wine…
So what kind of damage can pumping do to wine? From the top you want to gently press the grapes and have them release their juice. Crushing is actually a pretty harsh word. In crushing the concern is breaking the seeds and imparting the astringent tannins into your wine. (of course there are winemakers who utilize the tannins in both seeds and stems to great result! ie Brewer/Clifton)
Pumping can force through solids and then requiring additional filtration for your wine. Pumping also imparts oxygen into the wine and this can affect the aging of the wine. Pumping can be especially unwanted with the more nuanced varieties of wine like pinot noir as it can disturb the subtleties in the wine.
From an environmental standpoint it is reducing the energy use. You don’t have to pay for gravity on the electric bill! Building a gravity flow winery in the beginning will save you energy and equipment cost in the end.
So does it make the wine better? Well, it treats it more gently and after we torture the grapes on the vine, that seems to be the preferred method of treating them post harvest. It is energy efficient and seems to be kinda common sense (work smarter not harder!). In the end there are so many variables. When you use gravity flow you are again trying to have as little outside influence on the grape as possible.
After that it is in the winemaker’s hands. And…well before that it is in the vineyard managers hands, as well as the weather. So many variables.
All in all, a gravity flow system is an ideal, that can be put into practice with a little forethought in building. It is environmentally better and should in the long run be cheaper. As to it making the wine taste better? Maybe it’s time for a comparison test!? (Any excuse to taste more wine!)