Retronasal smell and why you taste beer after you swallow

Two ways to smell

You smell in two directions. Orthonasal smell is sniffing: aroma enters through the nostrils from the glass. Retronasal smell is aroma travelling from the back of your mouth up into the nasal cavity, mostly as you swallow and breathe out.

Both reach the same smell receptors at the top of the nose. But the brain treats them differently. Retronasal aroma tends to be experienced as taste, as if it came from the mouth. That is why people say a beer "tastes of mango" when mango is really a smell.

Why flavour blooms after you swallow

When beer is in your mouth, it warms up, mixes with saliva and releases more aroma. When you swallow, the throat squeezes air from the mouth up into the nose, carrying that aroma with it. Breathing out through the nose afterwards carries even more.

This is why many beers seem to bloom in the finish. A stout might smell of roast in the glass but deliver chocolate and coffee after you swallow. A hazy IPA might smell of citrus but leave tropical fruit on the exhale. The beer has not changed. You are smelling it from the other side.

Try the exhale test

Pour a flavourful beer, such as a Belgian ale or an IPA. Sniff it from the glass and note what you smell. Take a sip, hold it in your mouth for a moment, swallow and then breathe out slowly through your nose with your mouth closed.

Most people notice new aromas on the exhale. Compare the two impressions. Some notes are stronger on the sniff, others on the exhale. For a sharper contrast, pinch your nose while you sip and swallow, then let go. The rush of flavour when you release is retronasal smell arriving all at once.

What retronasal smell picks up best

Heavier, less volatile aromas that do not leave the glass easily often come through better retronasally, once the beer has warmed in your mouth. That includes many malt, roast, caramel and dried fruit notes. Some faults, such as oxidation or a faint diacetyl, can also be easier to notice in the finish than on the nose.

Mouthfeel and retronasal aroma work together too. A full-bodied beer coats the mouth and releases aroma over a longer time. A thin, highly carbonated beer releases a quick burst and finishes fast. Our guide to mouthfeel and body explains the textures that shape this.

Temperature, glass and tasting technique

Very cold beer releases less aroma both from the glass and in the mouth. If a beer seems bland, let it warm a few degrees and taste again. The difference can be striking with darker and stronger beers.

A glass with a narrower rim, like a tulip, concentrates orthonasal aroma. Retronasal aroma depends more on how you drink. Take a reasonable sip rather than a tiny one, let it move over your tongue, swallow and breathe out through your nose. Professional tasters often draw a little air through the beer in the mouth, a quiet slurp, to push more aroma towards the back of the throat.

Describing what you find

When you write tasting notes, separate aroma and flavour. Under aroma, write what you smell from the glass. Under flavour, write what you find in the mouth and on the exhale. The two lists will overlap but often differ in useful ways.

Our guide to beer aroma vocabulary gives you the words. If you want a structured way to build that skill, our guide to training your palate has exercises to try. The final step is calibration, tasting with reference samples and other trained tasters so that your retronasal notes match theirs, which is what a sensory course is built around.

Why this matters beyond the glass

Retronasal smell explains a lot about everyday tasting. It is why food tastes flat with a cold, why a beer tastes different with a meal and why sniffing a beer is only half of tasting it. Once you start paying attention to the finish, every beer has a little more to say.

It also explains why spices in food change a beer. Cardamom, cumin or curry leaf in a dish leave their own aromas in the mouth. Those aromas travel up the same retronasal route as the beer. Taste a beer alone first, then with food. You will notice the overlap.

Common questions

What is retronasal smell?

It is aroma that travels from the back of your mouth up into your nose, mostly as you swallow and breathe out. The brain often experiences it as taste.

Why does beer taste different in the mouth than it smells in the glass?

In the mouth the beer warms and mixes with saliva, releasing different aromas. Swallowing pushes them up into the nose from behind, so you pick up notes the sniff missed.

How can I taste more flavour in beer?

Let it warm slightly, take a reasonable sip, swallow and breathe out slowly through your nose with your mouth closed.