What is an alcohol unit?

A unit is a measure of the alcohol in your drink. It’s the same for beer, wine and spirits, and is expressed as grams of ethanol ⁽¹⁾. In South Africa, a unit contains 8g of pure alcohol ⁽²⁾.

The purpose of a unit is to provide consistency across beverage types and help translate the science behind drinking and health into something easily understood. This is important for providing drinking guidelines and advice. On average, it takes an adult an hour to process one unit of alcohol. However, if you weigh below 68 kg, it is important to realize that your body will take a longer amount of time to process alcohol. Women are generally affected more quickly by alcohol and by smaller amounts than men which means they should drink slower and less than their male counterparts.

Not all countries use the same unit size as South Africa ⁽¹⁾. Nevertheless, in each case, the same measure applies whether you’re drinking beer, wine or spirits.

Some places, like the US, also refer to a ‘standard drink’ rather than a ‘unit’.

For example:

• A standard unit in the UK contains 8 grams of ethanol
• In Australia and France, the standard is 10 grams
• A Mexican standard drink contains 13 grams
• There are 14 grams of ethanol in a standard drink in the US, Argentina and Chile

Units can help you understand drinking guidelines

It’s true that a ‘standard drink’ doesn’t always translate into how drinks are actually served. For example, many cocktails contain several different spirits or are mixed with wine or champagne, so they’ll most likely contain more alcohol than in a standard drink. Also, since wine comes in different strengths, and glasses are available in different sizes, the amount of alcohol you drink may not be standard. This is especially true if you’re at home and top up your glass before you’re finished.

However, the concept of a standard drink is still useful. Since the concentrations of drinks are different, a standard drink ensures that the amount of ethanol in a serving is always the same. This is important for sharing information about drinking and its effects on your health.

Using a standard drink allows for guidance on levels of drinking, regardless of whether the drinks are spirits, wine or beer. Plus, advice is generally given in terms of the number of standard drinks it’s best not to exceed in a day or a week, or on an occasion.