In the 19 years since she arrived in Philadelphia from Vietnam, Diep Phan never felt the need to hoard rice.

But with prices at an all-time high and spiking weekly, she goes out of her way now to store it up, she said yesterday outside an Asian market on Washington Avenue in South Philadelphia.

Economists say the reason prices are soaring is that exporters are holding back supplies to offset rising prices for food in their countries.

"The main reason that rice prices have spiked in the past 35 or 40 days has been due to export bans or restrictions by several major rice-exporting countries," said economist Nathan Childs, a rice expert with the U.S. Department of Agriculture.

And the reason for the restrictions, Childs said, is to offset rising domestic food prices inside the exporting countries - not due to crop shortages, or a global surge in the demand for rice.

Phan feeds her family of four, including sons ages 10 and 13, a meal with rice every day, a common practice among Asians.

"If my husband doesn't get rice every day, he complains that he's not full," she said, estimating her family goes through a 25-pound sack of the staple every three weeks.

That sack, which sold for about $12 in most area Asian supermarkets five weeks ago, was about $20 yesterday.

When Phan, a Philadelphia schoolteacher, saw last week that 25-pound bags were going for $16.99, she didn't hesitate to grab four sacks, anticipating it would go higher.

That phenomenon is happening all over the country - especially in cities with Chinatowns - as worried shoppers buy hundreds of pounds at a time, hoping to stay ahead of galloping price increases.

In California, some wholesalers, including Sam's Club, are restricting customers to no more than four bags of imported, aromatic jasmine and basmati rice, the varieties prized in Asian cooking.

"There's plenty of American long-grain rice, but once you've eaten jasmine rice you're never going back," said Eugene Pang, a Philadelphia rice broker for Bangkok Market, a Brooklyn, N.Y., distributor. "It's like having fresh squeezed orange juice as opposed to juice from concentrate."

Jenny Yuen, manager of Hung Vuong Supermarket in South Philadelphia, attests to the demand.

She estimated the store sells about 100,000 pounds of it a month.

While suppliers of most of the store's products allow payments over time, she said, rice suppliers, citing market uncertainties, require payment on delivery.

Thailand, Vietnam, India, the United States and Pakistan are, in that order, the world's top five rice producers.

Last September, India was the first major exporter to impose restrictions. Vietnam followed suit a few months later, and reimposed its ban last month.

While Thailand has not imposed an export ban, it is not entering into new contracts at the moment because of market volatility.

One measure of instability, said Childs, the agricultural economist, is the price paid for milled rice ready for export.

Basmati rice from the Punjab regions of India and Pakistan goes for $2,000 to $2,400 a ton, said Childs, adding that it was $850 a ton one year ago. Jasmine rice, currently shipping for about $1,080 a ton, was $560 a ton one year ago.

Tam Ma, 30, of Pho & Café Viet Huong, a Vietnamese restaurant at 11th Street and Washington Avenue, said the circumstances have forced him to raise consumer prices on some items too.

Where a side order of rice used to be free, now he charges from 50 cents to $1 for a small bowl.

And while he has managed to hold the line on the prices of rice plate entrees, he has raised prices slightly on the homemade, prepackaged rice-based dishes ordered to go because the profit margin on those dishes already was small.

A container of seven fermented rice balls, a desert delicacy, formerly sold for $1.25. Now it's $1.50.

Even small increases can add up, he said. On a busy Sunday night, the 35-table restaurant typically goes through 75 pounds of rice.

Contact staff writer Michael Matza at 215-854-2541, or