Pigging, or the use of sponge balls to move wine and clean transfer lines, offers enhanced sanitation, minimized wine dilution and reduced labor costs. It also can help achieve reductions in winery water use of up to 15%.

PIGs (pipeline inspection gauges) are inserted into transfer lines and then pressure-driven through the pipeline along with the wine and/or water by the use of compressed gas such as nitrogen.

After wine has been transferred, the PIGs can be used to bracket the cleaning solutions and rinse water while assisting in the cleaning of the lines. This makes the operation more efficient in water and energy use and cost.

Sonoma Wine Co. of Graton, Calif., used the Tool Lending Library (TLL) and advisors offered by utility Pacific Gas & Electric (PG&E) to implement their water-use improvements.

Measuring baseline water use

“The first thing to do is to get a good handle on your current water usage for the past several months before you adopt your PIGs. You’re going to need water meters, and PG&E can be very helpful in getting you started down the path to using good measuring devices for your winery,” says Richard Castle, the winemaker at Sonoma Wine Co. who took charge of the water project.

The winery measured total daily gallons of water used in its facility as well as the effluent for its pond by installing water meters and reading them daily.

In 2010, before beginning pigging, the winery’s water per case of wine measured 2.08 gallons; at the end of 2012, the measurement was 1.99 gallons. The 4% reduction included all water use in process areas. Most wineries do not separate water-use measurements by process unless evaluating specific equipment.

“A few caveats about water metrics,” cautions Natasha Granoff, who handles business development for the winery. “We have meters on water mainlines in and discharge out, then scattered meters internally but not to all process areas. We use our process waste numbers, less annual rainfall, as the water metric for managing and tracking water use. That may not be the best way to go, but it is our default method because we are regulated on our discharge gallons.”

Pigging procedures
“The PIGs are sponges made with natural-grade rubber with additives. You insert after the pump at the source, through a stainless ‘T fitting,’” Granoff explains. “Basically they act as a moving check valve by providing a loose seal with the inside of the line.”

The lines are lubricated with wine/water, which aids in the passage of the PIG. Nitrogen gas is used to push the PIG and the wine through the lines.

At Sonoma Wine Co., PIGs are removed from the lines after each use and cleaned between different lots of wine. They last for three to four months with daily use. Sanitizing can be performed either in an 85% ethanol bath or by microwaving for several minutes.

Does saving water mean using more energy? The winery reports the energy used for pigging was to pump, filter and move the water and wine, much of which would be moved anyway.

“Some of the water savings is offset by increased nitrogen use,” Granoff says. “However, less chemicals are needed to sanitize our lines; it takes half as long to push the wine to the tank compared to a water push, and the lines don’t require periodic treatment to remove stains.”

Other water-use reductions and behaviors

Other improvements at the winery to reduce water use included centralizing water intakes, capturing clean hot water for reuse, steam sterilization, barrel-washing recapture and, perhaps most important, behavioral changes and staff training.

With the pigging, behavioral and other improvements, annual water savings at Sonoma Wine Co. is up to 213,698 gallons, a 4% reduction.

“Richard Castle really took ownership of this project, researched and implemented,” Granoff says. “A fully mechanized water and pigging system with radio control costs in the thousands. Richard’s system cost less than $1,000 for supplies. The rest was in-house training, which he continues to manage.”

 “We’ve netted about a 4% drop in water use on a monthly basis across all of our cellar practices. That’s significant,” reports Castle. “By reducing water use in your ponds and elsewhere, you have the opportunity to bottle more wine under your curren t permit.”