It smells like what?

There really are some crazy descriptors out there for talking about wine aromas and flavours…did you know that a common aroma descriptor for Australian Reisling is garden hose pipe?!

This is where I guess some people lose faith in the wine world because it sounds like people are talking a load of B S. Just people trying to sound smarter than you by finding an aroma that would have never entered your brain even if someone was holding the word on an illuminated road sign.

Bare with me though, there is some science behind the madness!

The Grape:

This little berry is pretty lifeless while it’s still ripening on the vine because most of the aroma compounds are constrained by sugar but when it’s picked and fermented they’re free to play with our senses.

These aroma compounds present in the grape are also present in many other fruits and plants which explains why you might sometimes find a fruit or plant aroma in the fermented juice!

The Winery:

Here you have plenty of opportunities to add aroma compounds to a wine, either through fermentation processes, ageing and any additives that may be given to the wine.

Terpenes – a category of aroma compounds which generally refers to the citrus fruit and floral notes found in wine, such as Limonene and Citral but also includes Rotundone, a peppery note common in Gruner Veltliner.

Aldehydes – this category includes the grassy/leafy scents common in Sauvingnon Blanc called Hexanal and Hexenal, the vanilla notes common in oak aged Chardonnay’s called Vanillin and the marzipan and almond notes common in aged Pinot Gris called Benzaldehyde.

Pyrazines – these are the green bell pepper notes that you can often associate with Cabernet Sauvingon, Cabernet Franc and Carmenere. They are aroma compounds but can also be a sign of very young grapes since green pepper is basically just a young red pepper!

Esters – these are the primary fruit aromas found in very young, fresh wines such as red apple and pear. Some wineries like to ferment their wines in stainless steel tanks at cool temperatures to lock all of these esters in and ensure they are the stand out aroma compound.

Ketones and diketones – mostly floral and red fruit notes like violets and strawberries, often found in Pinot Noir. This category also includes the compound, Diacetyl which has a buttery aroma, common in Chardonnay’s and is the bi-product of malolactic fermentation (turning harsh malic acid into the mellower lactic acid).

Mercaptans – this set of compounds includes most of the tropical fruit notes such as passion fruit and guava, common in Sauvingon Blanc, along with the leafy and fruity blackcurrant notes often found in Cabernet Sauvingon.

Lactones – includes Sotolon, the aroma compound found in botrytised wines and Madeiras which adds nutty, toast and syrupy notes to the wine. Octalactone is the other Lactone that comes from oak ageing and adds a coconut aroma to the wine.

TDN – the kerosene aromas typical in aged Reislings which comes from the sun exposure on the grape skins.

Phenols – toasted, smokey and spicy aromas like clove derived from oak ageing.

So that’s the science behind it! So now you might have a good idea of why exactly you’re smelling green peppers in your Cab Sav and you’re not actually crazy for saying it out loud.


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