Controversy is brewing over single-serve coffee

If you received a one-cup coffeemaker - or a box of coffee for one - as a Christmas gift, by now you likely have brewed through and tossed out plenty of those little capsules, and perhaps you've started to wonder about the environmental impact and the value of convenience.

Turns out that many people have opted for such convenience: In the 12 months ending in November, nearly 46 percent of the dollars going toward the purchase of coffee or espresso makers went to single-serve machines, according to NPD Group, a market-research firm.

Keurig, a major player in the one-cup coffee business, reports that research it commissioned indicated that 13 percent of all U.S. offices have one of its brewers.

The company confronts the green issue head-on, saying on its website: "As the single-cup coffee market and our Keurig brewing systems grow in popularity, we understand that the impact of the K-Cup portion pack waste stream is one of our most significant environmental challenges."

The K-cup coffee and tea cartridges are difficult to recycle because they are made of three materials: a plastic cup, which is lined with a heat-sealed paper filter, plus a polyethylene-coated aluminum foil top. Keurig says the packaging keeps coffee fresh, but the cartridges are not biodegradable.

The Wall Street Journal has reported that nine billion cartridges have been sold. Keurig says it doesn't make that information public, but it did say sales of K-Cups more than doubled in 2011 over 2010.

"Finding a more environmentally friendly approach to this packaging challenge is a big priority for us," Keurig says on its website. "We are working on a few different fronts to improve the environmental characteristics of the K-Cup system." The company encourages consumers to put used tea and coffee grounds into a composter.

Keurig came on the market in 1998 and is popular not only in homes, but in offices, hotels, and other spots where making a full pot of coffee often is wasteful, or can lead to that burnt-coffee smell as a half-consumed pot sits on the heating unit too long. The company notes that its coffee drinkers don't have to grind beans, measure coffee, or clean a pot.