The itinerary was jam-packed – Heathrow at 6am, directly into a two-hour coach journey from Barcelona to the Pons olive oil company in Lleida to watch (and even help out with) the early harvest of their stunning olives, which have been grown there for centuries. Our host, Eduard Pons, guided us through the stunning valleys of olive groves, explaining that these early harvest olives were about to be transformed into some of the most prized and complex olive oils around – their beautiful green Arbequina olives are pressed within forty-eight hours of picking and represent some of the first oils of the season. The extracted oil is fresh and grassy – a dream for cooks seeking a fantastic finishing oil with a verdant, fresh and floral flavour. Cooking oil for a casserole, this most certainly is not.

The Pons family has now been producing olive oil for four generations, with Eduard taking over from his father Eduardo previously. While most of the trees are of the Arbequina variety, the company has a long history of open-mindedness when it comes to experimentation. A whole section of the groves is dedicated to housing more unusual, imported varieties of olive trees, which is not only exciting in terms of the different flavour profiles to be explored, but may also be a necessity in the future due to the changing climate, where knowing which trees will stand up to more tumultuous weather conditions will be a priority.

As well as new varieties of olives, Pons have also used some of their land to start cultivating grapes for wine production. After some rather shoddy harvesting on our part (we are nothing compared to the pros, who use electrical, pronged devices that gently quiver the olives from the trees) we happily sampled these wines atop a stunning terrace overlooking the valley.

After a tour of the winery, we headed to the olive oil factory in a nearby town. One of the most pleasurable, amazing elements of this was the incredible aroma that hits you as soon as you approach the doors of the factory. First, the green, bright scent of freshly picked olives, then the mellow discarded leaves, then the occasional wafts of every olive-y aroma you could think of as you wandered past various pieces of machinery.

We entered a room where the grinding of the olives took place – three huge, bell-shaped stones turning and grinding in unison with the most heavenly purple mush underneath, which omitted the juiciest olive smell ever – you could smell that richness of fat coming out of them, which of course is what you want for olive oil. Imagine the scent of a really powerful tapenade made from the best olives you could get your hands on, and you’ll come somewhere close.

We then headed next door for a proper tasting, presented with three little blue cups of oil that we were instructed to warm gently with our hands. The choice of blue glass instead of clear, Eduard explained, was to prevent an inherent bias for those bright-green, vivid oils that any olive oil buyer tends to gravitate towards at a food market. Lots of people will tell you that bright green is best, but this just isn’t the case.

What Eduard is striving to educate olive oil consumers about is freshness, which is a factor most people ignore completely when purchasing olive oil. It’s such a standard household item nowadays that most people barely give a second thought to where the oil comes from, but even if you’re opting for a traceable non-blended extra virgin olive oil, this is no guarantee of quality.

This year, mainly due to weather conditions, has seen a low yield of olives for Spanish olive oil producers, and this in turn can lead to a lower-quality product. As Eduard explains, many farmers may keep their smaller batches of olives longer until they have enough to take to the factory, and olives sitting around off the tree is not good for oil. If you taste woodiness, a metallic note or a kind of acrid aroma, your oil may well have come from some of these olives that have been sitting around for too long, or could have been processed with stagnant water.

As they say, though, the proof of the olive oil is in the tasting. The first one we tried was just one week old, and I had never tasted anything quite like it. It began with a really smooth grassy aroma, but then gradually a greater intensity of flavour crept in for a beautifully citrusy, fragrant finish. The comparison with the second oil (using olives from exactly the same trees but one year later) was astonishing. Although incredibly delicious to my fairly novice oil-tasting palate, it was incredibly mild, without any of that building and diminishing of flavour around the mouth that the first oil unleashed.

Our third oil was made using olives that are most commonly used in Spanish olive oil production, the Arbequina. It had a slightly sticky, fatty mouthfeel, with no real flavour travelling around the tongue. Had I not tried the previous two, as a punter I would have been pretty happy, but the difference was immense.

The fourth oil we tried was the freshest of them all. In collaboration with Belazu's chef-in-residence, Ross Gibbens, Eduard has come to the conclusion that, as freshness is key, a pioneering way forward would be to start freezing batches of the freshest olive oil to conserve and lock in that all-important flavour. Amazingly, this early-harvest olive oil is only defrosted when a trade customer puts an order in, ensuring that wonderful grassy flavour is as bright as possible when it hits kitchens.

All of this tasting came with a culinary message – that although many see oil as a kitchen cupboard staple without much thought, if we’re serious about our flavours, then we need to consider our olive oils in a new light.