Now this is a question worthy of seminars: Does using butter to thicken wine based sauces make them glossier? Boring question - but only on the surface.

'TOSSED' OR WHISKED?
Let's go back a little to when, in the company of Pierre Gagnaire, we went to make a presentation before a meeting of cooks in Madrid. How can two people be involved in the same presentation? Science has to demonstrate the results produced by science, cooking those produced by cooking but how do we explain the art? Would it not be enough to show it, and, in fact, to ask people to try it? Impossible: there were over several thousand present. Also, our discussions led us to restricting ourselves to using an original emulsion and to preparing a beurre noisette for use in a sauce called a kientzheim sauce which is prepared using the same process as for a mayonnaise but replacing the oil with melted butter, beurre noisette in the case in point. Why this choice of presentation? Because our discussions with Pierre often centre on the issue of the precise execution of a culinary act. Nothing simpler, to all intents and purposes, than preparing a beurre noisette and yet, it is a very difficult undertaking! How can we repeatedly obtain that colour, that aroma, that delicate taste? The public attending in Madrid seemed to have misunderstood the message, unlike those attending the INRA seminar on molecular gastronomy who were fired with enthusiasm over the issue of beurre noisette.

COMMENTS ON SAUCE GLOSSINESS
Having examined an apparently simple culinary production but one that was in fact very complicated, we thought it might be a good idea to start again from scratch. In cooking, what are the important actions? According to Pierre Gagnaire, 'tossing' wine sauces to which butter has been added is an essential step; this 'tossing' produces glossy sauces unlike those that are whisked. Now this is a question worthy of seminars: does incorporating butter into wine based sauces make them glossier? Boring question - but only on the surface. Here again, we had a fascinating seminar, especially because, unlike the previous procedure, those attending the seminar voted on a major change: the month's topic would be discussed right at the outset of the session, the results from the experiments being left until later. So we began by cooking a wine sauce finished off with butter. However, those attending were taken by surprise: this so-called wine sauce came down to water with a bit of gelatine! Why this simplification? Because a wine sauce is mainly made up of water and of the gelatine provided by the veal or poultry stock. This base was divided equally in two and butter added to each half. In the first case, the sauce was 'tossed' and, in the second, whisked. First comment: Although the colour of the two sauces was a bit different, glossiness is not a parameter that can easily be assessed, even when faced with two sauces that can be compared side by side. And this leads to the following question: what exactly is this "glossiness" cooks mention when talking about a sauce? Isn't it in fact limpidity? Or even clarity? The physical interpretation seems very simple: 'tossing' the sauce merely disperses the melted butter through the sauce in the form of droplets with the gelatine acting as an emulsifier; on the other hand, if we use a whisk, we inject air bubbles which lighten the colour of the sauce. Those attending the seminar did actually notice differences, not in glossiness, but in colour: the 'tossed' sauce is not as light coloured as the whisked sauce. This is the same sort of phenomenon as the one that turns gazpachos or even ganaches slightly rosy in colour.

ON USING A MICROSCOPE PROPERLY
However, this experiment carried out in public was only as good as the interest it attracted. Also, as the example it set: experimental science also takes care to compare systems that are identical in all aspects, with the exception of one single property; when there are several differences, it becomes difficult and even impossible to attribute the cause of a difference to a specific parameter. Back in the laboratory, the experiment was repeated but the sauces were observed under the microscope to find the air bubbles that were deemed to lighten the colour of a whisked sauce. Surprise! The expected bubbles weren't there, in the whisked sauce. The difference, between 2 sauces that were completely identical except with regard to butter emulsification, was the size of the oil droplets. In the 'tossed' sauces, the diameter of the melted butter droplets was about 10 times bigger than that of the droplets in whisked sauces. So that is the reason for this difference in appearance. However, seeing this difference made us think that the texture and flavour of the two sauces would be different. In fact, the larger droplets give an emulsion flow properties that are quite different to those produced by small drops. Additionally, the molecules that release aromas are soluble in melted butter and accessed in a different way: the flavour must be different.
And this leads to the following question: Does the importance of 'tossing' a sauce produce this glossiness as we assumed, or the flavour which is one of a cook's main points of interest? This wouldn't be the first time that flavour is seen as the important parameter, in a culinary operation that focuses on a secondary property: reducing sauces is also regarded as useful for eliminating "impurities". However, there is also cooking time that produces wonderful flavours. Another difference between the two sauces emerged when both had been allowed to rest: while the emulsion produced by whisking the sauce remained stable for some time, the emulsion produced by 'tossing' the sauce tended to break down quickly. The physicists did not find this surprising because they knew that the small drops of oil cream less quickly than the bigger ones but the cook has to allow for that: should he not mix for a long time to ensure that his butter is properly dispersed?

THE MATTER OF THE ACTION
The whole issue is pervaded by the mixing action. Let's take a moment to look at this action. It is an action that can be demonstrated but that is difficult to explain. The saucepan tends to move forward and then quickly back at which time we see the sauce propelled against the edge that is the furthest from the cook, hit the edge of the saucepan and then, like a wave, flow in the opposite direction. It's this wave that had us thinking that that this wave would have originally created the air bubbles. These bubbles would have been similar to the foam that edges a beach. Not so. It is clear that a metaphoric explanation is not enough. Additionally, it was this very type of intuitive interpretation that led to the non-existent concentration of so called reducing cooking process, to the apparently impermeable crust on grilled meat; that is the sort of intuition we need to fight through accurate analyses with the help of instruments that complement our ideas and our inadequate senses. That is why hotel schools, apprentice training centres, technological secondary schools, in fact all establishments where cooking is taught, should be equipped with microscopes and they should be found in the kitchen and not relegated to the back of the cupboards in the science rooms. The HACCP methods that so many pupils find off-putting? Show them the micro organisms in food, in kitchens and pupils will understand why precautions are necessary. More generally, let's analyse the cooking actions and reveal what lies behind the practices. That is how we will finally understand which actions are important and which are outmoded. We need to keep an open mind in the same way as recently did the parmesan producers who looked into the advantages of machines used to turn cheeses over. Up until now, the cellar men carried out this operation but this is expensive labour that the cheese-makers wanted to avoid using. So, because of the regulations on origin, they decided to organise a comparison of the moulds turned over mechanically with those turned over manually. They discovered a noticeable difference in flavour … because the heavy moulds meant that the cellar man limited the number of times they were turned over. This led some humidity to accumulate under the cheese; on the other hand, with the machine, there was no reason for delaying the turning over process. The machine idea was dropped as the result of a serious analysis of the actions involved. We need to heed this lesson. Sure. The food processor can help the cook but let's take a detailed look at the operations involved to find out when the food processor can and cannot help Man. A lot of water will flow under bridges before we can use a food processor to produce a wine sauce thickened with butter instead of 'tossing' it by hand. And finally, the matter of the action must not let us lose sight of the reason for this action. Are we going to mix a sauce? Fine. But the real question is: why do we do it this way? Asked like this, the mixing question takes on a different meaning: The technique takes a back seat because the time spent by the cook mixing, almost mechanically, could perhaps be used to advantage to query the pleasure that this action will give to the recipient of the sauce. He will be offered a wine sauce thickened with butter, certainly, but why? How? Will sufficient "care" have been taken in the preparation of this sauce? Let's take time to think about those to whom we will be feeding a wine sauce thickened with butter .... and prepared with love. Isn't this what makes cooking great?