Growing & Winemaking


Clean Wineries for Quality Wines

November 2013
by Peter Mitham
Consumers rely on the process of pasteurization to keep milk and fruit juices fresh, but for winemakers, fermentation is a must.

Sanitation and clean premises are still key concerns, however. Winemakers don’t want just any kind of fermentation taking place, they’re maitre d’s at a bacterial banquet ensuring the finest experience for their guests’ last supper. 

“The risk is that if we have a problem in the wine—the bacteria’s response, the yeast’s response—you spoil the wine, you’ve lost the wine,” said Pascal Madevon, winemaker at Culmina Family Estate Winery south of Oliver, B.C. “We want to produce high-quality wine, so it’s very important that the cleaning is good, because we don’t want any fear or deviation. The process needs to be very clean, to be sure we have exactly what we want: no bacteria, no development of what we don’t want.”

Design can help
    Water works

    Hot water and steam rinses are important elements in clean-up at Linda Donovan Wines in Medford, Ore. City water flows to her facility near downtown, providing clean water—something rural wineries sometimes struggle to secure.

    To round out the cleaning of her processing equipment, however, she uses an ozone rinse that serves as an effective contact sanitizer. American Equipment Co. in Portland, Ore., developed the rinse system, one of many options available to wineries.

    Col Solare, for example, uses a SGA21 ozone generator from Carlsen & Associates of Healdsburg, Calif., that delivers ozone into the rinse stream.

    The major consideration when using ozone systems, however, is to ensure appropriate ventilation. Ozone displaces oxygen in the lungs, and workers need to be aware and trained about how to avoid breathing difficulties.

    While the ozone generator at Col Solare delivers a measured amount of the substance to rinse water, winemaker Darel Allwine said good air circulation and ventilation is important for promoting ozone’s dispersal following the cleaning process.
Design and the choice of equipment can help foster and facilitate effective sanitation in the winery cellar.

Adequate lighting and ventilation, specific areas for cleaning barrels and building systems that deliver reliable hot water are key, as are subtle elements such as sufficient slope to the floors so that liquids flow toward a trench drain rather than pooling in corners and crevices where they can harbor colonies of microorganisms.

Culmina and many other wineries specify high-density, non-porous concrete for their crush pads and cellar floors. At Culmina, the fermentation cellar features high-density tiling from Germany’s Agrob Buchtal GmbH, while the barrel cellar is coated with Sika PurCem polyurethane from the Sika Group of Switzerland. It is easy to clean, shock-resistant and also anti-microbial in nature.

“It means in the cellar the floor is always clean, because the surfaces are perfect for that,” Madevon said.

Walls also receive attention at Culmina: They’re clad with galvanized steel fabricated at Samson Metals Inc. in Surrey, B.C. The covering ensures that splashed wine washes off easily without stains or residues.

A similar, easy-to-clean approach informs the choice of cellar purchases.

“Cleaning is an important consideration when I choose the equipment,” Madevon said.

A vibrating sorting table from Bucher Vaslin lacks a belt, eliminating moving parts that can catch berries and MOG, all of which are organic matter than can create breeding grounds for microorganisms. It’s efficient at sorting and saves time at clean up (though Madevon estimates the winery’s crew spends three hours per day during crush cleaning equipment).

Similarly, the destemmer is a Delta Oscillys destemmer crusher that has fewer moving parts than older models and reduces the effort required to clean the equipment from organic material and residues.

Material significance
Proper cleaning materials—not just ease of cleaning equipment—are critical to effective sanitation.

During a presentation to winemakers in Penticton, B.C., earlier this year, Gordon Taylor of Daven Lore Winery in Prosser, Wash., advised winemakers to follow the WATCH rule: water, action, time, chemical, heat.

“If you limit any one of these, you have to add something somewhere else,” he said. “So if you don’t have enough heat, then chances are you’re going to have to use more chemical.”

But which chemicals, exactly?
Boiling water may sterilize the wine thief between barrel samples, but the standby materials for Darel Allwine, winemaker at Col Solare Winery on Red Mountain in Washington state, include a generic sodium bicarbonate from American Tartaric Products Inc. (which he’ll occasionally neutralize with citric acid) with sterilization completed using Vortexx-brand peroxyacetic acid and (especially in the tanks) ozone.

Ozone “seems to help quite a bit, especially during harvest time, when we’re time-constrained as far as trying to move on to different tanks,” he said. “We can use ozone to kill the bacteria we’re looking to kill, and it does a really good job for us.”

Thoroughly cleaning the inside of hoses and pipes depends on being able to disassemble equipment for a thorough cleaning of gaskets, clamps and valves. In the case of hoses, foam balls from W.W. Grainger Inc. are ideal, Allwine said. Pressure allows basic fluid dynamics to push the foam balls through the hose, revolving as they go and gently scrubbing residues from the inside of the lines.

“It just pushes it up through to make sure the inside lining of the hoses and the pipes are cleaned very well,” he said. “They’re designed to actually get every inch of the inside wall surface of the hose you’re trying to push through.”

Col Solare’s cellar floor features Stonclad UT, a textured polyurethane mortar system from Stonhard in Maple Shade, N.J., t hat’s shock resistant and stays presentable as the winery’s equipment is disassembled and put back together.

While various measures exist to make sure cleaned equipment really is clean—from gauges ensuring consistent and adequate water pressure to thermometers that monitor the temperature of cleaning fluids—Taylor said good management practices and observation of what’s happening in the winery are fundamental. Do the right things, record that you’ve done the right things, then observe that things are going right, and a lot of sanitation problems can be avoided.

“My first line of defense is always sight, smell and touch. If it feels slimy, if it smells bad and it looks bad, then chances are it is bad,” Taylor said.

The downside of gravity flow
Among the hotspots Taylor singled out for special consideration when it comes to ridding a winery of bacteria are gravity-flow systems. Since they’re designed to carry materials downward, Taylor reminded winemakers that gravity-flow systems need to receive vigorous upward cleaning.

He advised growers to have a clean-in-place system at the foot of the line that can provide adequate turbulent flow up gravity-fed pipes, sufficient to lift debris and residues off the inside (he suggested a flow of 24-34 gallons per minute through a 1-inch pipe).

“Push up the line and clean it because the top of the pipe will always be dirty,” he said. “No matter how much chemical you throw down a gravity system, it will always be dirty because you can’t clean the pipe—it’s going to be open on top.”

Similarly, Taylor warned against dead legs in piping (places where liquids can stagnate for lack of adequate pressure). This frequently occurs when smaller pipes flow into larger pipes, with a consequent loss of pressure as cleaning water enters the larger channel. The flow of water is inadequate for cleaning the larger pipe, resulting in accretions of debris, residues and bacteria.

Clean fermentations
Trained in Bordeaux prior to coming to Canada a dozen years ago, Culmina winery’s Madevon said sanitation is even more important in the Northwest than at wineries where he worked in France because sugar levels are higher and, in turn, so are wine alcohol levels.

In British Columbia, he typically deals with wines in the 14% alcohol range, whereas in France it was more common to see 12.5% alcohol wines. The difference requires closer attention to providing the yeast with an ambient environment.

“We need to be very careful at the start to be sure there are good conditions for the yeast to start and to process. If you have contamination with such high alcohol levels, the risk is the yeast will slow down or stop, and you can be sure you’ll get some deviation of aroma. We need to be careful of that,” Madevon said.

Stuck fermentations are one possible consequence of high volatile acidity, but it can also contribute unfavorable characters to the wine.

“My goal is to have a very low level of VA, because after, I age the wine in barrels,” Madevon added. “We know (the barrels) are going to have an increase in VA…so I want to start, before the aging, with a very low level.”

‘Let God sort them out’
Perhaps the biggest risk to winery hygiene is the accumulation of nutrients and then bacteria in places such as valves, locks, the threads of connections, unpolished welds and the undersides of tanks, barrel racks and other areas that may come in contact with wine but are seen as secondary to the actual making of wine.

Taylor of Daven Lore Winery emphasized the importance of being proactive in cellar hygiene rather than reactive. “After something’s spoiled in the barrel, it’s too late to be good at it,” he said. “Chances are the wines are going to be good when the facility’s nice and clean.”

Taylor explained that three simple procedures could prevent problems from becoming major issues: cleaning, regular sanitation and sterilization.

“Cleaning is the removal of debris off the surface; you have to do that one first. Sanitation is the reduction of unwanted organisms. And then sterilization—basically, let God sort them out, we’re going to eliminate everything,” he said. “But if you haven’t cleaned something up front, and you’re sterilizing some filth that’s lying on top of your tanks, you’re not going to have it clean. It’ll just cover the surface, then some piece will break off and you’ll have problems; 98% clean is still 100% dirty.”

Currently no comments posted for this article.