Photograph: Jason Lowe.

Classed-growth Bordeaux has a liquidity and presence on the secondary market that’s driven predominantly by its volume, and the speculation played by those who purchase. This enables the tasting of back vintages to be an agreeably expensive yet accessible task. Yet the trade and clients alike do not have this luxury with the New World where – unless you have personally cellared a wine for years yourself – there is little to no opportunity to see a release of aged vintages. One of our most important values here at Berry Bros. & Rudd is the ability for us to speak authoritatively on wines that we have tasted and subsequently offer to our customers.

The chance to sample Old World wine aside, being able to taste mature vintages of Australian wine is a rare event indeed. Speculation on fine Australian wine is less of a concept for the collector or fanatic; hoarding the likes of Penfolds Grange with fervent zeal is probably more of a reality. Penfolds feed a huge fan base, with wines that find their way into cellars never to see the light of day until they are good and ready. This lack of older vintages on the market consequently presents us with a lack of tasting knowledge.

This gap in our understanding was the very reason we felt so privileged to recently find ourselves tasting a horizontal of Penfolds’ iconic wines from the famed 1990 vintage, hosted by chief winemaker Peter Gago himself. Some may see Peter as more of an ambassador than a winemaker, although in truth he is both, managing to reliably remain on top of the everyday workings of the winery. Peter is an enigmatic character; the showmanship and the passion can be seen by everyone, and an honesty both in him and his wines shines through. This made tasting through the 1990 wines all the more captivating.

This tasting comes at a time when we have seen another vintage with the same characteristics being released on the market – the 2010. Two years divided by two decades, each witnessing the planets aligning to produce the perfect raw material.

Before we threw ourselves into this epic experience, two questions remained with me, no doubt to be answered one way or the other by its end. The first question when I taste New World wine is do they ‘age’ or do they ‘evolve’? Do they evolve as gracefully as their Old World counterparts or do they age in a glacier-like manner with that omnipresent, thickly-fruited mid-palate core never really developing?

The second is a matter of regionality: more and more Australian wineries, in particular the likes of Penfolds, talk about the wines speaking of the land and a particular region, climate or soil type. The wines on show were from a variety of regions but with one common denominator – the 1990 vintage. In their immaturity, one can be mistaken for seeing an homogenous quality in them when the fruit is so full of youth and nervous energy. Differences are so miniscule as to evade many a taster’s palate. Will nearly a quarter of a century help clarify and polarise those regional differences, and will the wines’ true character shine through? In the concluding chapter of this account I shall reveal all.