Blood alcohol concentration (BAC) doesn't rise and fall symmetrically the way most people assume. The BAC curve is asymmetric: absorption is rapid (peaking within 30–90 minutes on an empty stomach), while elimination follows a slow, near-linear decline at approximately 0.15‰ per hour. This means a peak BAC of 1.0‰ takes roughly 6–7 hours to clear completely. Alcohol absorption happens primarily in the small intestine (about 80%) and stomach (about 20%). On an empty stomach, blood alcohol peaks within 30 minutes of drinking. Food — especially protein and fat — slows gastric emptying and can delay peak BAC by 1–3 hours, while also reducing the peak itself by 20–30%. This is why eating before drinking genuinely helps. The elimination phase is governed by alcohol dehydrogenase (ADH) and follows zero-order kinetics — meaning your liver processes a fixed amount per hour regardless of how much is in your blood. This rate is approximately 7–10 grams of alcohol per hour for most adults (NIAAA, 2023). Drinking multiple drinks in quick succession creates a steep absorption curve that overshoots your liver's capacity, leading to a much higher peak BAC than the same drinks spread over hours. This is why drinking pace matters enormously: 4 drinks in 1 hour can produce a BAC of 0.8‰, while the same 4 drinks over 4 hours might peak at only 0.3‰. The Widmark formula models this relationship and is the standard used by forensic toxicologists worldwide. It was developed by Swedish chemist Erik Widmark in 1932 and accounts for alcohol consumed, body weight, gender-specific water distribution, and time. Sources: NIAAA "Alcohol Metabolism," Widmark (1932), Jones (2010) "Alcohol Pharmacokinetics."