EVERY morning millions of Americans confront the latest trend in commodities markets at their kitchen table. According to the United States Department of Agriculture, rising prices for crops—dubbed “agflation”—has begun to drive up the cost of breakfast. The price of orange juice has risen by a quarter over the past year, eggs by a fifth and milk by roughly 5%. Breakfast-cereal makers, such as Kellogg's and General Mills, have also raised their prices. Underpinning these rises is a sharp increase in the prices of grains such as corn (maize) and wheat, both of which recently hit ten-year highs. Analysts are beginning to ask, as they have of oil and metals, whether higher prices are here to stay.

On the face of it, that is an odd question. After all, if the world runs short of corn or wheat, farmers can simply grow more, weather permitting. That is exactly what they have been doing. In the coming year, the International Grains Council, an industry group, estimates that global production of grains will reach a record of 1,660m tonnes, well above last year's figure of 1,569m. But demand for grain is growing even faster. The council reckons it will reach 1,680m tonnes this year. In three of the past four years, demand has exceeded supply.

The culprit is the growing use of grains to make biofuels, such as ethanol. Most grains are used as food either for people or for livestock. But the increase in human consumption has been slowing for decades as population growth moderates. Demand for animal feed, meanwhile, has grown steadily, as more people in booming countries such as China grow rich enough to afford meat.

Demand for biofuel feedstocks, by contrast, is soaring. The amount of corn used to make ethanol in America has tripled since 2000; ethanol distilleries now consume a fifth of the country's corn crop. And America is only one of 41 countries where governments are encouraging the use of biofuels to reduce oil consumption.

As a result, demand for grains has accelerated. During the 1990s, when oil was cheap and biofuels unheard of, demand grew by 1.2% a year, according to Goldman Sachs. But in recent years, it has increased by 1.4%, and over the next decade, Goldman projects, it will rise by 1.9% annually.

Farmers are struggling to keep up. The Economist Intelligence Unit, a sister company of The Economist, projects that demand for corn, at least, will continue to exceed supply until at least 2009. Moreover, even to produce as much corn as they are now, farmers are growing less soya and wheat, and so pushing up the prices of those crops too. With all the main grains to feed poultry and livestock becoming more expensive, the cost of meat and eggs is rising, and so it goes on.

When demand was growing more slowly, farmers could meet it through gradual improvements in their yields. But to cope with today's boom, yields will have to rise much faster, or farmers will have to bring more land into production.

Both are possible. Greater adoption of genetically modified strains of corn and wheat, for example, could improve yields. But they are expensive and politically controversial. There is also quite a bit of fallow land to be sowed, especially in developing agricultural powers such as Brazil and Ukraine. But those countries are far from the biggest markets and their idle land tends to be found in areas with poor transport links. A strong price signal will be needed to overcome such obstacles and induce extra supplies.

But even if new land is planted, argues Jeffrey Currie of Goldman Sachs, it will not necessarily reduce the cost of grains. Since high oil prices and generous government subsidies ensure that biofuels are profitable, any extra grain will be used to make more of the stuff. That will not dent the oil price, since the volumes remain tiny compared with global oil consumption. Instead, the price of biofuels has risen to that of petrol, and the price of corn and crude oil, the main feedstocks for the two, have converged (see chart). For grain prices to fall, Mr Currie argues, either governments must pull the plug on biofuels programmes, or the oil price must fall.

Neither seems very likely in the near future. This week America's Congress is debating whether to double its targets for biofuel production. At the same time, the oil price rose to its highest level in ten months, thanks to a strike and other disruptions in Nigeria. The chaos in the Niger delta, it turns out, has a surprising amount to do with the price of eggs.