Domestic Science: Cold-Water Washing, Powered by Enzymes
Heat isn't the only force of nature that can loosen molecules of grease and dirt from clothes and speed up cleaning.
In the annals of green living tips, cold-water wash is a classic. Wash your laundry on cold, and you save the energy needed to heat up the 40 gallons of water used in a typical load. Another classic: Buy concentrated laundry detergent. Less packaging means less waste and less energy used transporting the stuff to you.
These ideas have proven tough sells, though. Companies that market cold-water detergent estimate that consumers choose cold water for about two-fifths of all loads, and sales have declined over the past year. There are proven environmental benefits to washing in cold water—one household can avoid emitting more than a metric ton of carbon dioxide each year—but the corresponding savings on the electric bill, around $60 per year, are less impressive. That hasn't been a strong enough incentive for most launderers to abandon hot water, which has a deserved reputation for cleaning clothes better than cold water.
But heat isn't the only force of nature that can loosen molecules of grease and dirt from clothes and speed up cleaning. A company called Novozymes, a branch of the Danish drug-maker Novo Nordisk, has been working with detergent manufacturers to develop enzymes to tackle stains in cold water. Novozymes specializes in the production and commercialization of enzymes, proteins that can help break down organic materials. The company works on a wide range of problems, including biofuel production, in which enzymes help break down complex carbohydrates like corn into the simple sugars that get processed into ethanol. Enzymes can make similar short work of corn syrup spilled on a favorite sweater during a failed baking experiment.
"I never knew how hard a chocolate ice cream stain was to break down until I did this," says Adam Monroe, president of Novozymes North America. "The problem is not really the chocolate in the chocolate ice cream; it's the gum that they put in the ice cream that's the stain issue."
The company has a library of enzymes that can solve particular stain problems—when a customer comes in with a request, the company starts pulling enzymes off the shelf and testing their efficacy. (The company's researchers do a lot of laundry.) "We find a lot of these enzymes in nature," Monroe says. "Then we work to make them even more efficient."
Enzymes have been part of detergent formulas for years, and with control of 47 percent of the world's enzyme market, Novozymes is a leader in the field. But only recently has the company begun imagining how enzymes can make products like detergents more environmentally friendly. Besides making cold-water washing work, enzymes can replace petroleum-derived elements of detergent and reduce the total volume of detergent needed. Novozymes is thinking now about how enzymes could help reduce the amount of total water needed for wash cycle. The enzymes also biodegrade, Monroe says—the company worries more about enzymes breaking down too quickly, before a product is used, than about enzymes lingering in the water supply.
Some green living tips demand more personal sacrifice than they offer gain, even if every person in America took them up. But cold-water washing isn't one of them. Up to a quarter of a home's energy use can go into heating water—for dishes, for showers, and for the 400 loads of laundry that a typical family does each year. Hot-water washing isn't a necessity or a luxury, though: At this point, it's a waste.