Red Pistachios: Why They Were Dyed (and Why They Vanished)

Pistachios were dyed red to hide blotchy stains on their shells. It was cosmetic, not a flavor, a variety, or anything to do with the nut inside. For most of the 20th century, the pistachios sold in the United States were imported, and the way they were harvested left the shells marked. Dyeing them bright red covered the blemishes and gave the snack a memorable look. Once American growers started producing clean, unstained nuts at scale, the reason to dye disappeared.

Why were pistachios dyed red?

The honest answer is presentation. Before the 1970s, the bulk of pistachios eaten in America came from overseas, primarily Iran and the wider Middle East. Traditional harvesting there did not hull and wash the nuts immediately after picking. Pistachios grow inside a fleshy outer hull, and when that hull stays on the shell, its natural oils and tannins leach out and leave blotchy brown and yellow stains. The marks were purely cosmetic. They did not affect taste, texture or safety, but they looked unappetizing on a snack stand. Importers solved the problem by dyeing the shells a uniform, eye-catching red (and, less often, green or white), so the staining vanished under a coat of color.

Over time the color stopped being a fix and became an identity. Through mid-century vending-machine and snack culture, red simply became the color Americans associated with pistachios. People expected to crack open a red shell, and their fingertips turned pink in the process. That association is why so many older shoppers remember red pistachios with real fondness, even though it was never how the nut naturally looked.

There is also a fonder, fuzzier origin story, and it is folklore. Food writers sometimes trace the red-dye habit to a single New York pistachio vendor, often named as Zaloom, around the turn of the 20th century, who supposedly dyed his nuts red to stand out on stands and in vending machines. It's a charming tale repeated across food media, but it isn't a documented historical record, so treat it as a legend rather than established fact. The broader import-staining explanation is the one that multiple outlets agree on.

Was the red dye dangerous?

No, and the route of exposure made it even less of a concern. The colorant was applied to the shell, which people throw away, so very little dye ever reached the part you eat. The specific dye isn't firmly documented in any primary source; reports variously describe a synthetic red food coloring (Red 40 is the one most commonly named) or vegetable-based dyes, so it's most accurate to call it simply a red food dye.

On general dye safety, the picture is reassuring, with a few limits. According to the Cleveland Clinic and Healthline, FDA- and EU-approved food dyes are considered safe at permitted levels, though a minority of people may be sensitive, and some studies have linked artificial food dyes to worsened hyperactivity in some children. In April 2025 the FDA announced plans to phase out several synthetic dyes, including Red 40, from the food supply. None of that is specific to pistachios, and given that the shell was discarded, dyed pistachios were never a meaningful source of dye in anyone's diet.

Why did red pistachios disappear?

Two forces ended the practice within about a decade: a homegrown industry and geopolitics.

The American pistachio industry traces back to botanist William E. Whitehouse, who collected nuts in Iran in 1929 and returned around 1930 with roughly twenty pounds. According to American Pistachio Growers, one selection, the "Kerman" variety, named for the Iranian city, became the basis of essentially all of California's commercial trees. The first commercial California crop was harvested in 1976 at around 1.5 million pounds, and the state now grows the overwhelming majority of US pistachios.

California's harvest is mechanized and fast: the nuts are hulled, washed and dried within roughly a day of picking, before staining can set in. That produces clean, natural tan shells and removes the entire reason to dye. Geopolitics then accelerated the shift. After the November 1979 Iran hostage crisis, President Jimmy Carter imposed trade sanctions that cut off Iranian pistachio imports. According to reporting in The Counter, US consumers were cracking open roughly 20 million pounds of imported Iranian pistachios a year in the 1970s, while domestic California production climbed to around 27 million pounds by 1980. In 1986 the US imposed steep antidumping duties on Iranian pistachios that further protected the maturing California industry. By the late 1980s, with abundant unstained domestic supply and curtailed imports, red dyeing had largely vanished.

Today, dyed pistachios survive mainly as a nostalgia novelty. If you're curious about the nut beyond its color, read what is a pistachio, how the pistachio plant grows, and why the kernel is its natural green color. And if you'd rather drink your pistachios than crack them, see how to make pistachio milk or what goes into a pistachio latte, and mark the calendar for National Pistachio Day on February 26.

Allergy note

Pistachios are a tree nut, and red dyeing never changed that. The colorful shells contained the same allergen as any other pistachio. They are unsuitable for anyone with a tree-nut allergy, and cross-contamination is a real risk where nuts are processed. If you're avoiding the nut itself, note that pistachio milk and pistachio creamer are also tree-nut products, even though many are dairy-free and vegan. When in doubt, check the label and speak to a medical professional.