"I've been curious, because food consumption varies how the alcohol is absorbed," Steve Boykin of Raleigh told ABC11 while on a visit to Hibernian Irish Pub in Raleigh.
Personal breathalyzers that claim to accurately measure a person's blood alcohol content are flying off the shelves. A Massachusetts based research group estimates the market at $215.2 million - up from $27.9 million just four years ago.
But do inexpensive - they go for as cheap as $40 online - personal breathalyzers really work?
ABC11 put a $60 version to the test - starting with reporter Rebecca Hall who was not drinking. It registered zero for her.
Next, we tested bar patron Rick Regan who'd skipped lunch and had a beer and a half in his system. After less than two beers, he blew a .12. That's well beyond North Carolina's legal limit of .08.
Law enforcement officials we spoke with weren't surprised.
"I would not put my faith in them and drive a car once I blow into it," offered Wake County Sheriff Donnie Harrison.
Harrison says while it's good that people are making an effort to avoid drinking and driving. The store bought devices can't be trusted in legal terms.
"Some people are affected by alcohol that will blow under .08 that are impaired because maybe they never drank before, younger people. [For] a lot of us, it's what they had to eat in their body," he explained.
Regan wasn't depending on the breathalyzer results before making a decision about driving, but his friend Steve Boykin said the machines have an appeal.
"Be much cheaper than insurance and a ticket," he said.