Ever wondered how they get scents like vanilla into that bottle of wine?
We were tasting three Chardonnays, all New World. An unoaked. An oaked. A late harvest. Contrasting the noses of the first two, I talked of how oak treatment can lend some buttery, creamy, vanilla and nutty characters in addition to fruit; while the un-oaked bottle smelt only of quite citrusy fruit. A second-year hospitality management student wants to know, because she can clearly detect a vanilla note – “Why do they put vanilla in?”
It’s a variation on the: “When do they put the peas in?” question that I clearly remember (asked by an adult, during a tasting of Sauvignon Blanc).
Both questions address the very pertinent and often perplexing issue of why wine smells of so many things plucked from everyday life. The aforementioned student also mentioned she could only smell grapes on the unoaked Chardonnay.
I said that was probably wishful thinking as, bizarrely, to make things even more complicated, wine almost never smells of grapes. What is it about the fermentation process that puts an apparently humble fruit through such a profound sensory transformation?
First and foremost, many of a wine’s characters result from where and how the grapes were grown, and seem to “survive” fermentation. Here we’re talking about soil and mineral content – in other words geology – plus weather and most particularly sunlight hours – in other words geography.
But there are vast numbers of other minor constituents in a grape that contribute to the ultimate flavour/smell of a wine. Proteins and amino acids (the latter are the “building blocks” of protein) assist in the development of yeasts during fermentation.
We’re getting way into chemistry here, but let’s continue with glycerine. We understand this as a slightly sweet tasting syrup, and it is partially present in the original pressed juice. But it’s further formed during fermentation, and brings the smoothness and body to a wine, which together have a profound effect on the manner in which aromas/flavours are delivered.
So amino acids and glycerol and so on interact and play a large part in the formation of complex aromas/flavours during a wine’s maturation process.
There are other factors. Those fruity aromas, which may seem to have nothing to do with “grapiness”, arise because of compounds contained in the cells contained on the grape skin’s inner surface. These are components we cannot “smell” until we start to process grapes in the fermentation process.
This close association between aroma compounds and skin contact is more obvious in red wine (where skin contact is in any case critical) but is now being increasingly explored in the creation of white wine.
But there are other aromas entirely the result of winemaker intervention, which obviously includes the use of oak. But how to smell oak. Does anyone here, I asked in class, go around kissing trees? Laughter all around. Vanilla and cream are easy to identity, as are nuts and toast. Cigar boxes, maybe. I start students on smelling fresh pencil shavings. But how may people even use traditional pencils anymore?
Annabel Jackson has been involved in the wine industry for more than 20 years, variously as educator, writer, public relations consultant and event organiser.
Read past Out of School columns here.