Why are some pistachios red?

The first pistachios available to consumers were imported from the Middle
East. American importers dyed the shells red, both to disguise staining from
antiquated harvesting methods and to make pistachios stand out among other
nuts in vending machines.

Until the 1970s, there was no domestic pistachio industry in the United
States. California harvested its first commercial crop in 1976. The entry of
California pistachios into the marketplace made available nuts with clean,
naturally tan shells. California's Kerman variety is also larger in size
with a more vibrant green nut color. A small percentage of California's crop
is dyed red, not by necessity, but to meet the needs of those consumers who
prefer the colorful shell.

Maybe Its The Brining?

Santa Barbara Pistachios are machine harvested in early October, using the
most modern equipment available. First, we determine when the pistachios are
completely ripe and have opened naturally on the tree. Then, the nuts are
shaken from the trees onto a catching frame, never touching the ground.
(Each tree takes less than ten seconds to harvest). We then load our
pistachios into containers and rush them to the processing plant, where they
are hulled, dried, graded, sorted and put into refrigerated storage. As
orders are received, our Certified U.S. Fancy, the highest grade nuts, are
brine soaked in 100% natural flavors, hot air dried and packaged for
shipment.

Commercial harvesters have machines to shake the fruit down over tarps. The
pistachio is a drupe, which means it has an outer fleshy covering over the
hard-shelled nut, like the nutmeg. The fruit is gathered and then soaked to
remove the outer soft red or yellow covering before the hard shells
containing the nut are dried in the sun.

Maybe its the CORNSTARCH BLEACHING THAT MAKES YOU SICK?

The pistachio nutshells which surround the pale green nutmeat are naturally
a creamy light beige color. So where did that deep reddish-pink color come
from? Food historians have conflicting explanations. One source says the
tradition originated with the aforementioned Syrian importer named Zaloom,
who dyed his pistachios red to distinguish them from his competitors.
Another holds they were dyed to mask mottled markings, a natural result of
the drying process, to make them look more palatable to consumers. On the
other hand, natural-colored shells that are overly light have been whitened
using large amounts of cornstarch and salt. The mottled, naturally-dried
shells may not be as attractive, but they have no effect on the flavor of
the nutmeat itself.

Carlstadt, NJ (SafetyAlerts) - The Food and Drug Administration (FDA) said
today that Skinner's Salted Nuts Inc. is recalling certain 'Skinners Nuts
Salted Red Pistachios' because the product contains undeclared FD&C Red No.
3 and FD&C Red No. 40.

LOL Ouch! No I don't eat the shells.  Quite a bit of that dye actually does
make it onto the edible part though.  From what I know, the plain pistachios
are about 5 grams of carbs per 30 nuts.  Just wondering if anyone new if the
dyed ones have higher carb counts. Thanks Joe