What counts as one drink

By the end of this lesson you can count standard drinks for any glass you serve. Every judgment you make behind the bar, from pacing a table to refusing service, starts with an accurate count.

One standard drink

A standard drink is a fixed amount of pure alcohol: 17.05 millilitres, which weighs 13.45 grams. The glass changes. The alcohol inside a standard drink does not.

In Canada, each of these holds one standard drink:

• A bottle of beer (341 ml at 5%)
• A bottle of cider (341 ml at 5%)
• A glass of wine (142 ml at 12%)
• A shot of spirits (43 ml at 40%)

Look at the pattern. The stronger the liquid, the smaller the serving. Beer is weak but comes in a big bottle. Whisky is strong but comes in a small shot. Each one delivers the same alcohol to the body.

Alcohol has the same effect no matter which beverage carries it. A guest who "only drinks beer" is not drinking lighter than a guest sipping whisky. Three bottles of beer and three shots of rum put the same alcohol into two bodies.

Counting real pours

Real servings are often bigger than the standard sizes above. You can count any pour with one calculation: multiply the volume by the alcohol percentage, then compare the result to 17.05 ml.

Try three pours you will actually serve:

• A 500 ml can of craft IPA at 8%. That is 40 ml of alcohol. Call it two and a third standard drinks in one can.
• A 9 ounce glass of wine (256 ml at 12%). That is about 31 ml of alcohol, so almost two standard drinks in one glass.
• A double rum and coke (86 ml of rum at 40%). That is about 34 ml of alcohol: two standard drinks in one order.

You will not do this math at speed on a Friday night. Do it once for your menu instead. Learn which of your products hide more than one standard drink, and count those guests accordingly.

Why the count matters

Canada's health guidance draws a clear line for a single occasion: more than 2 standard drinks in one sitting raises the risk of injuries and violence, for the drinker and for the people around them. The guest with two tall craft cans is not at two drinks. They are close to five.

Some situations call for zero alcohol. The guidance names driving a motor vehicle, using machinery, taking medicine that interacts with alcohol, and being responsible for the safety of others. Keep that list in mind when a guest tells you they are the designated driver.

Your count is also your evidence. When you slow service or refuse a guest, you are acting on what they actually consumed, not on how many glasses you remember clearing.

How the body takes alcohol in

Alcohol absorbs into the bloodstream through the mouth, the stomach, and the intestines. It needs no digestion, so it starts to act quickly.

Food changes the speed. Proteins and fats slow absorption down. An empty stomach speeds it up. Fast drinking piles new alcohol on top of alcohol the body has not yet processed. This is why a guest who skipped dinner and orders two quick doubles can change in front of you within half an hour.

The practical move for a server: offer food early, especially to a table that is ordering rounds quickly. Every plate you land on that table slows the alcohol down.

The trap to expect on the test

The test likes drink-equivalence swaps. A question may suggest that a bottle of beer contains less alcohol than a shot of spirits. It does not. Both are one standard drink. A question may also describe an oversized pour, like a tall craft can, and tempt you to count it as "one drink" because it is one container. Count the alcohol, not the container.

Recap

• One standard drink is 17.05 ml (13.45 g) of pure alcohol: a 341 ml bottle of 5% beer, a 142 ml glass of 12% wine, or a 43 ml shot of 40% spirits.
• Alcohol affects the body the same way whatever the beverage.
• Big or strong pours hold more than one standard drink. Count the alcohol, not the glass.
• More than 2 standard drinks in one occasion raises the risk of harm. Some situations, like driving, call for zero.
• Food slows absorption. An empty stomach and fast drinking speed it up.