Tasty week – olive oil, wine technology and the physiology of taste

We’ve had a lovely oily tasty sniffy week, with our first oil tastings and some coaching on olfaction and taste thresholds.

Our oil guy, Alessandro Bosticco, is an inspired teacher, a sommelier as well as an olive oil expert, and I was happy to hear he’ll be steering us through some wine tastings as well. I particularly warmed to him when he dodged a question about his favourite olive oil by saying that he simply loved tasting new things, and if he were offered the choice between his current favourite and one he’d never tried, he’d take the one he’d never tried.

He said oil tastings were rare, even in Italy, and to do them as we were, by tasting oil from cups (rather than by dipping bread) was still fairly unusual. We tried four different kinds on each of the two days. Oil is what carries flavour to our tastebuds, and it does its job well; so, being oil, its flavour is hard to purge from the palate. We had to allow more time between tastings than we would for wine, and take sips of bottled water and slices of apple – granny smith being the apple of choice for oil tastings because it is the most acidic.

We heard about the craze for fresh, unfiltered oils in Bosticco’s own local oil-producing region (Tuscany): cloudy and bright-coloured, these oils are not, he said, good for the long run, because the particles in them are fibres that have not been extracted during filtration, and which will trap water which can in its turn trap bacteria. So murk or sediment will affect the oil’s flavour adversely over time, and he advised that if you intend to keep your oil more than a few weeks, to get a clearer one. Even then it’s not going to last more than about 18 months, with a steady decline in colour and flavour as time goes by. More than once he remarked that the oil you taste today is as good as it’s going to get: it is not a product that improves with aging. Rather it is a living thing that changes over its lifetime. And it’s vulnerable to heat and light, so store it accordingly

We got some pointers on reading labels, and learned about the legal designations of “olive oil”, “virgin olive oil” and “extra virgin olive oil”, as well as a few others, defined by the International Olive Oil Council.

Basically the big deal with extra Virgin Olive Oil is that it must be produced by mechanical means (which is always and inevitably cold pressing, so that phrase added to labels is just hyper marketing). This distinguishes it from the processes used to produce all other kinds of oils (except for specialised niche versions of course), which involve heat and chemicals. Extra virgin oil has to pass a chemical test (it can’t contain more than .8% oleic acid) and it then has to pass a taste test by a panel of experts. This doesn’t guarantee it will taste ‘good’ to everyone, but it gives a basic measure of quality. It may also be the result of blending more than one crop, including crops of different years, but is tested at bottling, so no new blending can taste place once it’s had its testing.

There’s a statement which for 2 years now must appear on bottles of Extra Virgin Olive Oil: it must be described as “superior quality oil obtained straight from olives using only mechanical means of production.” That again is no guarantee of flavour (which is subjective anyway) or origin. Most of the olive oil in Europe is produced in Spain, but Italy has the highest consumption, ergo much of what we describe as Italian olive oil is imported and only bottled in Italy.

So for those who want Italian and only Italian olive oil, there is a fairly recent DOP designation (Denominazione di Origine Protetta, or Protected Denomination of Origin) – a high falutin’ version of extra virgin, which is subject to standards governing where and how the olives may be grown, pressed and bottled as oil. This oil of course sells at a considerable premium. It would be one instance where the bottler will note the date of harvest on the bottle, giving you an indication of the freshness and therefore the power of the oil’s aroma and flavour.

Farther down the scale, what is sold simply as Olio d’Oliva, or Olive Oil, is a blend of refined (by chemical means) olive oil and virgin olive oils. Virgin Olive Oil is produced by mechanical means and has a higher measure of oleic acid than Extra Virgin.

Olive oil is used in its traditional market – Mediterranean, for example – for traditional reasons such as taste. In the newer and ever expanding world-wide markets, it’s been picked up for its health benefits, as it’s a pure unsaturated oil containing fat-soluble vitamins (A and E) and antioxidants. Among the many other advantages it has over other oils, as enumerated by the Oil Council, when you use it for frying, it adds less fat to fried foods because it forms a crust on the surface of the food that impedes the penetration of oil and improves the food’s flavour.

There are different taste preferences for olive oil that are partly cultural: people raised on animal fats tend to prefer milder olive oils to more pungent peppery ones with their bitter after-bite. We had a reinforcement of the advice about becoming a good taster: to taste and smell many different things in order to build an olfactory library, so you have a more comprehensive memory of tastes and flavours to compare.

Due to some weird global synergy, BBC Food Programme and NPR both had programs on olive oil this month.

We also had a first lesson on wine technology… ack – more chemistry. Still, we are paddling around in the sea of knowledge and one day it will all make sense.

We finished the week with a lesson on the physiology of taste from Mirco Marconi. We’d heard already about the classification of taste – sweet, salty, bitter and acid (plus the newcomer, umami, which reflects ‘meaty’ tastes). We learned that the position of taste buds on the tongue is not as static as had originally been supposed, with fixed areas for each taste, but that they are in fact in an overlapping range of regions with the central area of the tongue the least sensitive.

Bitter tastes linger longest because of their placement on the sides of the papillae where the flavour gets ‘stuck’ until it is washed out. We heard that there are varying proportions of the world’s population who are unable to taste bitter (3% in West Africa, 40% in India, 30% of white people in North America; 37% of Italians).

We heard about two theories of taste, which are called either molecular shape theory vs molecular vibrational theory, or docking criteria vs swipe card model. The first supposes that there is a ‘lock and key’ relationship between odorant and receptor: odorous molecules have shapes and sizes that “fit into” the shape and size of corresponding olfactory receptors. In the second, it’s supposed that receptors in the olfactory organs recognise molecules by their vibration, so the nose acts as a kind of spectroscope.

We got into hands-on mode for some tastings and sniffings. We sipped our way through nine samples representing sweet, salty, acid, bitter, umami and astringent – substances dissolved in water – comfortingly straightforward. We then finished by attempting to identify thirty different olfactory samples, ranging from smoke to mint, from cloves to coconut and saffron to bergamot. Fiendishly difficult.

And finally, we were welcomed to Parma officially before Christmas, and here’s the official photo!