Published on 04/20/06

Research results: pick no peanut before its time

By Brad Haire
University of Georgia

A peanut's taste has a lot to do with when it's harvested, says a University of Georgia professor.

A peanut that can muster a "roasted peanutty" taste is the crème de la crème of the peanut butter industry, which most Georgia peanuts are grown to supply, said John Beasley, a crop scientist with the UGA College of Agricultural and Environmental Sciences.

But sometimes after being processed, a peanut can have an off flavor, tasting a little like paint or cardboard, among other things a peanut shouldn't taste like, he said.

Beasley has conducted research over the past three years to learn, along with yield data, how newer peanut varieties and an established variety taste, when harvested early, on time and late.

In randomized tests, he harvested newer peanut varieties like Carver, AP-3, C-99R, Georgia-01R and Georgia-02C 10 days early, on time and 10 days late. He did the same with the industry standard variety, Georgia Green.

Selected peanuts were sent to two flavor-testing labs. Across the board, the time of harvest dictated how tasty the peanuts were, he said. Peanuts harvested too early had an off flavor.

But waiting too long to harvest can be bad, too. A farmer can lose as much as 300 pounds per acre in yields if peanuts are harvested too late. Georgia farmers averaged about 2,870 pounds per acre last year.

"But Georgia has maintained a reputation for having the best, most consistent-tasting peanuts around because our growers get the crop in when it needs to come in," Beasley said. "We need to continue doing this, because the peanut industry is competitive, and consumers will taste the difference."

Not all peanuts are equal. They don't mature at the same time. Late-maturing varieties take 155-160 days to mature. Mid- maturing varieties take 135-140 days.

But environmental conditions can throw maturity dates off, he said.

That's why farmers need to use the hull-scrape method and not just count days. With the hull-scrape method, the thin, outer- layer of the shell is scraped off. The hue of the remaining shell is compared to a profile board. The darker the hue, the more mature the peanut is. "It's still the best way to know the maturity of peanuts," Beasley said.

Although new varieties are making their way into farmers' fields, the workhorse continues to be Georgia Green. The UGA peanut breeding program released it in 1995 as a mid-maturing, disease-resistant, high-yielding and flavorful peanut. It alone accounted for 70 percent of Georgia's 755,000 acres last year.

Tomato spotted wilt virus hit Georgia peanuts hard last year. It infected about 8 percent of the crop, a level not seen since the mid-1990s, when the disease became the primary concern for the industry.

"Farmers and the peanut industry are always looking for more disease-resistant, higher-performing varieties," Beasley said.

And the peanut consumer will always be the final judge, he said.

Cool, dry weather in the fall of 1986 prompted many Southern farmers to harvest peanuts early. That resulted in many immature peanuts making it into peanut butter. The problem soon became obvious, when the industry started getting reports of sour- tasting peanut butter.

Some Georgia farmers have started planting peanuts this year. But using a UGA index that helps farmers reduce the risk of tomato spotted wilt virus, most now plant peanuts in mid-May. They harvest them in late September and October.

Brad Haire is the former news editor with the University of Georgia College of Agricultural and Environmental Sciences.