BAC stands for Blood Alcohol Content. BrAC stands for Breath Alcohol Content. For all intents and purpose, they are one in the same when it comes to breath alcohol testing. This is because a person’s blood alcohol level can be accurately and conclusively measured via a breath sample.

There are many variables in how your body processes alcohol. Firstly, the more you drink the higher your BAC will be. Other factors include: the strength of the alcohol consumed; how fast it is consumed and over what period. There is a misconception that x number of drinks per hour will record the same reading for everyone.

Your weight: The more you weigh, the more water is present in your body. Water dilutes the alcohol and lowers your BAC.
Food in your stomach: Absorption will be slowed if you’ve had something to eat as the alcohol will have less direct contact with the stomach lining.
General fitness and metabolic rate are not constants and fluctuate for a variety of reasons.
Gender is also an important variable as women generally have less water and more body fat per pound of body weight than men and alcohol does not enter fat cells as easily as other cells so more alcohol typically remains in the blood of women.

Your BAC will only continue to rise once your body can no longer process alcohol as quickly as it is consumed.

A large amount of consumed alcohol can be detected for up to 12 hours after consumption has ceased. There have however been instances of up to 24 hours later.