Wine tasting is always fun.
Recognizing the varietal character of the various grapes via aroma and flavour and how these can vary from region to region or vintage to vintage is always interesting.
Then assessing any winemaker input and if this enhances a wine. eg. oak, MLF, bâtonnage can be challenging.
And then of course there are the technical components like fruit/acid balance, alcohol content, length of finish, faults etc.
But to get technical, taste is limited to just five aspects (but usually only two, maybe three, in wine) and we are probably more interested in the various flavours that wine exhibits.
Sweet, sour (acid), bitter, salty were the original four tastes and then umami was added and recognized properly around the year 2000.
Umami is a savoury, meaty and brothy taste dried shiitake mushrooms, Vegemite, kombu seaweed, miso and parmesan cheese.
In our mouths there are particular receptors that are sensitive to each type of taste.
Sourness and saltiness are about ions going through ion channels. The other three tastes work with G-protein-coupled receptors.
Flavour recognition comes from other sources.
According to Dr. Alex Russell, a taste and smell perception expert, flavour is a 'hedonic' sense involving smell, texture, temperature and expectation.
Let's, as an example, look at a New Zealand Marlborough Sauvignon Blanc.
Gooseberry, passionfruit, capsicum, herbaceous and grassy are the common flavour descriptors used for this most distinctive and easily recognizable wine.
On a molecular level, there are 3 individual chemicals strongly associated with this Marlborough wine that give it this flavour profile. For the chemistry boffins out there they are hexyl acetate, trans-3-hexan-1-ol and 3-mercaptohexyl acetate (3MHA).
But I digress.
When in the mouth, the actual taste of the wine would be acid.
But the actual fruity flavours come from smell.
This smell is not entering the nose via the nostrils at this point. It's entering the nose through the throat.
This perception of odours from our smell receptors via the throat is called retronasal olfaction. Perception of odours through the nose is called orthonasal olfaction..
So when 'tasting', you'll get the temperature of the wine in your mouth, that's the touch sensation. You'll get the acidity. That is the actual taste itself.
And you'll get the fruitiness from the smell through retronasal olfaction.
Put all of those elements together and that's flavour.
By the way, that tannin component of wine (mainly in reds), that makes your mouth pucker is not generally a taste or a flavour although an excess can impart a bitterness. It is normally a mouth feel or a tactile sensation.
Something to think about (or probably not) when taking your next sip of wine.