With increasing populations and dwindling supplies of potable water in many parts of the world, many advances have been made – water-saving toilets, showers and washing machines, low-flow faucets and waterless urinals.

But one inefficiency that until recently has been largely neglected is the substantial amount of water used in cooking at Asian restaurants. So why not develop a waterless wok?

Because the burners generate lots of heat, conventional wok stoves consume a lot of water due to the constant flow that cools the cook top to prevent it from buckling.

In addition, water is used for rinsing the wok after each dish is prepared and for cleaning the cook top. Cooling jets and the swivel spout or tap are often left on, even when no cooking is occurring.

Edward Maher of Sydney Water, a utility provider in Australia, says waterless wok stove installations have shown that water waste can be reduced by as much as 90%, with full ROI within one year.

“The average water use of a conventional wok stove is 5,500L (1450 gallons) a day, and in Chinese restaurants – which account for up to 50% of all Asian restaurants – it can be as much as 8,000L (2115 gallons) a day.

“With waterless wok stoves, the need for cooling water is eliminated because the stove has an air gap that insulates the stove elements and releases the heat to the kitchen exhaust. A spout that cuts off water supply when the stove is not in use is also provided, and some units have a knee-operated lever on a timer tap to limit the flow rate and duration to a small reservoir used in cooking.

“If the flow rate is reduced from 12L to 4L (3.1 gallons to 1 gallon) a minute by eliminating wok stove cooling water and waste, a saving of $A5,400 ($US4,545) a year can be achieved. In Sydney Water’s area of operation there are about 2,000 wok stoves, so if 5,000L can be saved from each unit every day, then restaurant industry profitability will increase by $A9 million ($US7.5 million) a year, and Sydney would save about 3.6ML (950,000 gallons) a year.”

Melbourne company B&S Commercial Kitchen Appliances designs and manufactures waterless wok cookers and waterless steamers for use in Asian restaurants.

General manager Dean Skalistis says the need for water deck cooling has been eliminated with the new design, which minimizes heat transfer from the wok support ring.

“This not only ensures a reduction in water usage but also results in a decrease in sewer usage and waste discharge fees – as well as less long-term maintenance, as there are no leaking rings to repair.

“Other water-saving features include the WaterSet wok spout, which can be activated only while over the wok pan, and the optional knee-operated laundry arm valve that is fitted with an automatic timer. This latter feature helps to minimize water usage by chefs when filling their reservoir, as only 10-20 seconds of water flow is fed through the laundry arm at a time.

“More than 100 of our waterless wok cookers, which cost about the same as conventional units, have been sold Australia-wide, and we get many inquiries from overseas.”

In conjunction with Sydney Water and National Project Consultants (NPC), Thornthwaite Technologies in Sydney helped to develop the waterless wok stove by supplying the knee-operated Presto 712S valve that is fitted to the B&S units.

Managing director Andrew Thornthwaite says the Presto 712S incorporates unique security and anti-blocking technology that prevents the chef from allowing water to run continuously.

“This valve ensures water flows only when the knee wand is pushed and released. Even if the chef ties the wand back, water will not flow until the wand is fully released.

“Added hygiene benefits come from the fact that the valve is operated without any hand contact, which reduces cross-contamination in commercial kitchens.”