As of June 30, the TSA will limit the amount of powdered substances allowed in carry on baggage to 12 ounces.

That may seem generous compared to the measly 3 ounce requirements for liquids and gels, but could spell trouble for passengers traveling with souvenir spices and coffees.

And if you’re wondering if coffee can technically even be considered a powder, American Airlines issued a statement to clarify the issue: “Powder-like substances are described as fine dry particles produced by the grinding, crushing, or disintegration of a solid substance (i.e. flour, sugar, ground coffee, spices, powdered milk, and cosmetics).”

Powders may be subject to additional security screenings and, if agents aren’t able to identify it, may insist on throwing it out. To avoid any headaches, the TSA urges passengers to pack any powdered substances over 12 ounces in checked luggage.

According to the TSA, agents will be testing for explosives along with powders like fentanyl, pepper, and other chemicals that could be used to harm passengers mid-flight.

The new rule applies to international flights bound for the U.S. as a result of last July’s thwarted terrorist plot to bring down an Etihad plane in Australia using powdered explosives. There restrictions were introduced for domestic flights last summer.

As many travelers have experienced with TSA screenings, what individual agents allow is not always in line with TSA policy. With that in mind, passengers traveling with powdered substances marked by the TSA as being exempt from this new rule (baby formula, medications, and, yes, even the cremated remains of a loved one) may want to have a backup plan ready just in case.

Above image by Lukasz Janyst via Shutterstock