CHICAGO (CBS) — It’s this year’s must have kitchen gadget. The Keurig coffee machine promises a single cup of piping hot coffee in just seconds and sales have doubled every year for the last three.

But as CBS 2’s Dorothy Tucker reports, the Keurig coffee maker is leaving a bitter taste in some mouths.

They are really popular, but their convenience comes at a cost – to our wallets and the environment.

It’s easy to find fans of the Keurig coffee machine

“I just really like how fast it comes out. You push the button, it’s ready – made in a minute,” said one shopper.

“It’s very convenient and the coffee’s never cold,” another shopper said.

Each serving is individually brewed in a small plastic container called a K-Cup.

“It’s easy, it’s fast and I just take it out and throw it away,” one shopper said.

That’s troubling to environmentalists like Cindy Luppi of Clean Water Action.

“Our concern is that they are not recyclable and that means they end up in the landfills and incinerators and impact our health. The emissions end up in the air we breathe, in the water that we drink,” she said.

With the number of K-Cups being tossed increasing, that means a lot of plastic that’s not being recycled.

They’re hard to recycle because they’re made with a variety of materials. There’s the plastic cup, then an aluminum cover and an inside paper filter.

“It’s also typically too small to be recycled. The trend is that larger materials are accepted typically in recycling programs,” Luppi said.

In a statement, the company said, “Reducing the environmental impact of our packaging materials and brewing systems is a top priority for Keurig. It is a challenge to create a portion pack that is recyclable. … Keurig is actively working to meet this challenge head on.”

Another issue is cost. You can pay an average of 75 cents for each cup. That’s a lot more than it costs to brew a traditional cup of coffee at home, which generally runs from 5 to 7 cents a cup.

But hot coffee in just 40 seconds is appealing and, despite the higher cost, and the environmental criticism, users are loyal.

Several companies are now making Keurig-style machines. Additionally, other companies have started packing their coffee in the K-Cups, including Dunkin’ Donuts.

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