Have you noticed that your coffee tastes different lately? A little bolder, perhaps even bitter? Does it seem to have more caffeine?

Coffee companies are sneaking more robusta beans into their grounds as the price of the higher-grade arabica beans has spiked, Reuters reports. Very few roasters are actually admitting to doing this, but the evidence is as plain as day: U.S. robusta imports soared by 80% in the first quarter, while arabica fell by nearly a third.

Higher-quality arabica beans have a milder, more delicate and complex flavor than robusta. They're harder to grow and more expensive. Coffee experts say robusta, by contrast, tastes like burned rubber. Robusta also has a lot more caffeine.

Robusta coffee has been dismissed for years. In fact, U.S. coffee merchant COEX Coffee International never traded robustas five years ago, Reuters reports. Now the company said 40% of its business is robusta.

That raises a big question: Who's using all that robusta? Reuters guesses it's the national retail brands sold in supermarkets. Only one major roaster has admitted to using more. Massimo Zanetti, which makes the Chock Full o'Nuts and Hills Bros. brands, said it upped its robusta content by more than 25%, according to Reuters.

Everyone else is quiet.

There's only so much robusta Americans will take in their coffee blends. And roasters seem to be pushing the limit -- an understandable move, given the wild increases in coffee prices in recent years.

But coffee prices have come way down. Arabica futures hit a two-year low this week, in fact. So will the roasters that switched to robusta return to higher-quality arabica now that costs have settled? Unless there's a consumer backlash, the answer is no.

Shoppers on tight budgets are trading down to less expensive coffees, willingly accepting a slightly harsher taste in order to save a few dollars. That means robusta's popularity is probably here to stay, and the coffee industry is adjusting to this new reality. That's good news for Vietnam, the world's biggest grower of robusta.

How does a coffee bean make it to your cup? The following video traces coffee's journey.