Linda Hogan -- I Was NOT Driving Drunk Before Bubbly Arrest

Linda Hogan insists ... downing ONE glass of champagne before getting behind the wheel isn't enough to put her in the DUI category -- pleading not guilty today to driving under the influence after her October arrest.

TMZ broke the story ... Linda was popped for DUI in Malibu after cops say she was speeding around town with a blood alcohol level of .084 ... just over the legal limit in CA.

At the time, a rep for Linda said Linda drank one glass of champagne at a jewelry event that night ... on an empty stomach ... but she also had taken antibiotics, which exacerbated the effects of the alcohol.

Nevertheless, Linda was subsequently charged with two counts of DUI. She pled not guilty today.

If convicted, she could face up to 18 months in jail ... though it's unlikely she'll spend any time behind bars since she has no prior DUI convictions.