It is a phenomena that doesn't make you sick, but can be upsetting.
The good news is that it is rare, and it only lasts maybe 2 weeks.
The Food and Drug Administration has some reports on it, but we don't really know how often it's occurring. After a doctor wrote a medical article about it when he experienced it, the problem got lots of attention and lots of people saying "I had that."
The problem is now known as "pine mouth."
It happened to James Matarese a few weeks ago. He'd been snacking on pine nuts, also known as pignolis
"It was a day later and I had experienced a bitter after taste, almost a metallic type taste," he said.
The feeling in his tongue had changed.
"I pretty much could not taste anything sweet. It dulled all tastes," he said.
James did what many frequently do. He Googled it, and there it was - pine mouth. He found a report from the FDA saying, "The agency found that the majority of pine nuts associated with "pine mouth" were eaten in the raw state (either as snacks or as a component of salad or pesto sauce."
"It's not dangerous. It's very disconcerting for the person that it's happening to, but it's a benign condition, meaning that it goes away and usually won't come back," Dr. William Reisacher of NYP Cornell said.
Dr. Reisacher has been researching taste problems for a medical article. While we know nut allergies are somewhat common, he says pine mouth is not an allergic reaction.
"This is what we call an adverse food reaction, which is different from an allergic reaction," he said.
The pine nuts that James ate came from China, as many do.
Another supermarket with pine nuts "not" from China still puts a warning to its consumers, right on the package.
Only 1/3 of the dozens of different species of pine nut are edible and that could be the cause.
"What is believed to have occurred is that pine nuts that should not be eaten ended up into the food source from China, although no one is really sure.
"I've regained my taste. Everything is good. But I won't be eating pine nuts made in China," Matarese said.
Some people who have had the reaction say they got it from nuts that came from other countries, so that still is a mystery. Pignolis are common in Italian baking, but no reports are linked there. It's mostly the raw nuts and only in some people. The good news, again, is it goes away after a maximum of 2 weeks. But anyone experiencing it should call reach out to the FDA, so they can track it.