Most of what you call taste is actually smell

Hold your nose and eat a jelly baby. You will get sweet, and you will get chewy. You will not get strawberry.

The tongue is a fairly blunt instrument. It reports five things — sweet, sour, salty, bitter and umami — plus the trigeminal sensations that are not really taste at all: the burn of chilli, the cooling of menthol, the astringency of tea. That is the whole list.

Everything else is aroma, and it does not arrive the way you would expect. Smelling a strawberry before you eat it is orthonasal olfaction, through the nostrils. What happens while you chew is retronasal: warmed volatile compounds travel up the back of the throat to the same receptors from the inside. Your brain files the result under "taste" because it arrives at the same moment as the sweetness, and because your mouth is where your attention is.

Why this changes how a flavour is built

It means the difficult part of a strawberry flavour is not the sweetness. Sweetness comes from your formulation. The difficult part is a set of volatile compounds present at parts per billion, in the right ratio, released at the right moment during chewing or drinking.

It also explains three things every manufacturer eventually runs into:

• A flavour that reads perfectly at room temperature can fade when chilled. Cold suppresses volatility. Less aroma leaves the product, so less reaches the receptors.
• A cold you cannot taste through is not a taste problem. Nothing has happened to your tongue; the passage to the olfactory receptors is blocked.
• Two products with identical sugar and acid can taste nothing alike. The measurable numbers on the specification are the part that is easy to match.

When we build a flavour to a brief, most of the work is in the fraction of the formulation that never registers on a Brix meter.