Have you ever though about how far you can shoot a champagne cork? The swedish physicist Hans-Uno Bengtsson has actually done the necessary calculations in the wonderful Swedish book “Kring flaskor och fysik” (which translates to something like “Among bottles and physics”, it was written together with sommelier Mischa Billing). Assuming a bottle pressure of 6 atmospheres, a cork length of 25 mm (the part in contact with the bottle), a radius of 9 mm and a mass of 7.5 g, this gives an initial cork velocity of approximately 20 meters per second or 70 km/h! This translates into a maximum shot length of around 40 m (if we neglect air resistance). In case you prefer not to shoot the cork, you could of coarse turn to a saber or a heavy kitchen knife instead to open the bottle.

When opening a bottle of champagne, you might have noticed the cloud forming right above the bottle neck (see picture below). This is due to a significant temperature drop, caused by gas expansion when we open the bottle. Assuming an adiabatic expansion (meaning no heat exchange with the surroundings), Hans-Uno Bengtsson has calculated a temperature drop of 112 °C! No wonder the vapor around the bottle neck immediately freezes forming a small cloud.

(picture by polarunner at flickr.com)

If this doesn’t satisfy your craving for champagne science, there’s a whole book on the subject: “Uncorked - The Science of Champagne” by Gérard Liger-Belair. He’s an associate professor of physical sciences at the University of Reims Champagne-Ardenne and probably knows more about champagne bubbles than anyone else! In addition to many fascinating pictures of bubbles, the book has many interesting facts. Did you know that:

(these facts should be perfect conversation starters!)

(photo by Gérard Liger-Belair)

An interesting article by Gérard Liger-Belair, “Effervescence in a glass of champagne: A bubble story” is available from Europhysics news.

Happy New Year!

Over Christmas I have been reading Luca Turin’s book “The Science of Scent”. This became a real eye-opener for me with regards to my understanding of how the sense of smell works. (BTW, Luca Turin was also featured in Chandler Burr’s book “The Emperor of Scent” which I haven’t read yet).

The first part of the book includes a lot of basic chemistry (which can be skipped if you’re familiar with chemistry) plus descriptions of many perfumes and perfume ingredients which made we wish the book came with it’s own smelling strips. But then comes the interesting part. I have always thought of smell to be a result of molecular recognition - a typical interaction between a drug and a receptor or and enzyme and a substrate. The reason I guess is that this seems very intuitive - just like a shape sorter toy for children! I had also read a review article on “Structure-Odor Relationships” (Rossiter, K. J. Chem. Rev. 1996, 3201). Now the interesting thing is that this might be wrong (or at least not the whole truth - and scientific controversy is always exciting)!

Luca Turin suggests that it is the molecular vibrations of a molecule that we recognize as it’s smell. In an easy accesible article on this (at least for chemists), Turin puts up pro’s and con’s for both theories, including the following:

A very recent review entitled “The Nose as a Stereochemist. Enantiomers and Odor” (Bentley, R. Chem. Rev. 2006, 4099.) mentions Turins work, but with a short dismisal:

… a theory by L. Turin proposes inelastic electron tunneling to account for the biological transduction of molecular vibrations.[35][36] Recent experiments to test predictions of the theory found no evidence to support it [37]…

Reference 35 and 36 can be downloaded from www.flexitral.com - the latter needs to be saved/renamed as a pdf before opening. The contents of 37 is described here. It’s surprising however that Bentley uses ref 37 to disprove the vibration theory, because the authors refer to their own work as “… a paper of solely negative results”. What they did was to perform experiments, partly outlined in Turin’s book, that suggest that molecular vibrations alone cannot explain all aspects of smell. Despite the controversy, Luca Turin and his company Flexitral have been quite succesful in designing new odorants, especially stable odorants which imitate other, less stable molecules. The development of these new odorants is based on designing stable molecules with vibrations similar of the molecule it’s supposed to imitate.

But the story doesn’t end here: Very recently, physicists at University College London reported that they have discovered a physical mechanism that would allow a receptor to distinguish different molecular vibrations (read press release, preprint and SciAm news report). Put simple, the researchers have shown that when a molecule with the correct vibration binds to a receptor, a switch closes allowing electrons to flow. This means that there is experimental theoretical evidence that supports the vibration theory!

Now what does all this have to do with molecular gastronomy and food? When we talk about taste, it’s actually 80% aroma and 20% taste (more on this page). And with aroma, we’re talking about the smell of volatile molecules. Luca Turin touches upon this on the very last pages of the book were he writes that “An area which, in my opinion, is ripe for revolution is that of flavours”. Perhaps it will be possible one day to “synthesize” any desired odor (or aroma!) with a set of molecules (or condiments) with different molecular vibrations?

This is not exactly breaking news, but I just recently discovered that Robert L. Wolke, a retired chemistry professor and author of “What Einstein told his Cook” (volume one and two), writes a food/science column in the Washington Post entitled Food 101. Readers post questions which are then answered. One reader asks:

Why does a pot roast brown in a crockpot? It seems to be steaming in the pot, which one would think would create a blanched and pale cut of meat, but it comes out as browned as if we had seared it on the stovetop (not that I’m complaining).

[…]
Now, did I say the Maillard browning reaction involves parts of sugar molecules?

Yes, I did.

Does that mean there are sugars in the meat?

Absolutely not.

Then what the. . . .

Easy, now. Let me explain.
A carbonyl group is indeed a certain grouping of atoms found in sugar molecules. But it also is found in many other kinds of molecules, including the meat’s very own fats and proteins. The Maillard browning process can use the carbonyl groups that are inherent in the meat; it does not require sugars. And that’s fortunate, because there are no sugars in meat, beyond perhaps traces of glycogen, a source of glucose that fades away following the animal’s death.
[…]

Check out the other posts - there’s a lot to pick up for anyone interested in the food and science (especially if you like Wolke’s anti “tech speak” jargon - otherwise I would suggest reading McGee instead)!

This must be a true holiday treat: Eat miraculin for Christmas and everything sour will turn sweet! Reading Joseph Mallozzi’s blog post on his visit to Jeff Ramsey’s Tapas Molecular Bar in Tokyo, I became aware of the miracle fruit. For one of the dishes, the guests are asked to eat the flesh of the miracle fruit and keept in in their mouth for one full minute. Following this the guests are given grapefruit which then tastes sweet! The miracle fruit is not sweet by itself, but the tongue will perceive sour foods as sweet for one half to two hours after it has been treated with the miracle fruit.

Picture from Wikipedia.

The active compound is a glycoprotein named miraculin. It consists of 191 amino acids linked together (the sequence can be found here). From what I have found, it is not known how miraculin interacts with the taste receptors on the tongue.

Unfortunately it seems to be quite difficult to get hold of the miracle fruit as they perish quickly. A couple of years ago however, a Japanese company developed a technique to freeze dry the fruit and desserts made with the fruit are served at the Miracle Fruits Cafe. Apparently, miraculin is available in tablet form in Japan (more info in Japanese here).

This year, japanese researchers were able to transfer a synthetic gene, encoding miraculin, into lettuce. The miraculin produced by the transgene lettuce had the same taste modifying properties as the miraculin found in the miracle fruit. But since it appears the FDA has turned down an application for marketing miracle fruit, it doesn’t seem likely for neither the miracle fruit nor the transgene lettuce to reach the super market next door… But I still hope Santa will bring me some miraculin for Christmas!

As a follow up to last weeks statement from Adria, Blumenthal, Keller and McGee (article, my comments) The Guardian have interviewed Heston Blumenthal. He now says that MG creates artifical boundries: “Molecular makes it sound complicated,” he says. “And gastronomy makes it sound elitist.”. And Heston isn’t keen on either (at least not anymore…).

According to Hervé This, there’s still some 25.000 cooking instructions left to test! And when it comes to the understanding of how the sense of smell works, we’ve just got started. So sorry Heston, I think it’s a bit early to dismiss molecular gastronomy already now.

Under the heading “The Curious Cook” Harold McGee recently started an occasional column on food and chemistry and everything in between in the New York Times. It’s definitely worth reading as Harold McGee has time and opportunity to really dig into these matters. Also, don’t forget to check out his blog. The latest post on his blog provides more detail on the blue-green colors in garlic and onion, discussed in the NY Times column.

The day of St. Lucia is celebrated in Scandinavia and some countries in southern Europe on December 13th. In Scandinavia a traditional kind of bun, lussekatt, is normally made and eaten on this day.

Lussekatt (Photo by Jonas Bergsten)

What is exciting about this from a chemical perspective is that they are made with saffron, the world’s most expensive spice (a recipe can be found here). Because of the high price, saffron is sometimes adulterated with turmeric. There is however a simple chemical test to check whether your saffron has been adulterated or not.

The color of saffron comes mainly from crocin, a carotenoid with a sugar attached that makes it water soluble (this is why the color is so easily extracted into water containing foods):

The aroma arises mainly from the degradation of picrocrocin to release the terpene safranal:

The yellow color of turmeric comes from curcumin.

Upon reaction with a base, curcumin turns bright red whereas crocin is unchanged. Because of this it should be possible to detect whether saffron has been adulterated with turmeric. In the picture below, strips of coffe filters where inserted into suspensions of saffron and turmeric in water (two of each), and those on the right where then held over a bottle of aqueous ammonia. An immediate reaction takes place between ammonia and curcumin, producing a bright red color. I should quickly admit that I haven’t had the opportunity to test this on an “authentic” adulterated sample!

BTW, the color change is very fast as is obvious from the video below (click here if it doesn’t play in the window below):

On Sunday, November 10 2006, in The Guardian, Ferran Adria, Heston Blumenthal, Thomas Keller and Harold McGee shared a statment on the “new cooking” with the readers. They feel “widely misunderstood” and argue that molecular gastronomy is “overemphasized and sensationalized”. Quite a surprising statement from people who have benefited greatly from the increased attention that molecular gastronomy has received lately. On the other hand - many journalists still tend to be stuck up with Heston Blumenthals snail porridge and egg & bacon ice cream, so I can agree that molecular gastronomy is not always properly understood. The four main points in their statement (with my comments) are:

Well certainly no one can disagree with the first statement… As for tradition - of course cooking has evolved a lot over the last couple thousand years - so again I would say that this is quite obvious. What molecular gastronomy (in my opinion) is about is, from a scientific viewpoint, to increase the understanding of what is going on. Tradition tells us nothing about this whereas science has told us a lot!

I guess this is where molecular gastronomy (or the-science-previously-known-as-molecular-gastronomy as ABK&M might call it) comes in. I note that they only embrace it though if it “can make a real contribution” to their cooking. In other words, they embrace they technological aspects of molecular gastronomy which according to Hervé This’ latest definition isn’t really a part of molecular gastronomy.

Again - nothing really new here… except that one could always wish for even more sharing and openness regarding techniques and ingredients. But all in all ABK&M have been good at publishing their recipes and findings (as should be evident from the books listed at khymos.org). Of course this also alludes to the intellectual property debate which was started of by this article.

So what do we make of this? First thing is that none of them are scientists (save McGee who holds a BSc in physics and who BTW has defined molecular gastronomy as “the scientific study of deliciousness”). In a way it’s understandable that they don’t want to be viewed upon as scientists but rather artists. But it is a little strange though, because the article does have a negative stance on molecular gastronomy. This is surprising from a group of people who have both benefited from and contributed to molecular gastronomy by adding an artistic component to the underlying science. Secondly I wonder if it’s about fashion as well. Perhaps the air is going out of the balloon now? If molecular gastronomy is not übercool anymore, it’s time to move on with something new to attract guests. But is it really time to “reject the cult of molecular gastronomy” (Vanessa Thorpe of The Guardian, in the article “Mad scientist? No, I’m just seroious about food”)? If you ask me, my answer is “No”!

In a recent Science article (Science 2006, 314 (5803) 1235 (requires subscription, but text has been posted in a newsgroup), Martin Enserink writes about Hervé This and molecular gastronomy. One of his projects is to rid cook books of the many errors.

One of This’s obsessions is that chefs, despite knowing so little about science, have developed such elaborate laws. Over the years, he has meticulously collected more than 25,000 instructions, called précisions in French, from cookbooks, many of which are useless, he says. So where do they come from? “Our parents love us. Why are they teaching us all these rules that make no sense?” His hypothesis: Cooks, using trial and error, remembered the circumstances in which they created a successful dish, even if they were irrelevant, and made them part of the recipe.

The article also touches upon the different views Harold McGee and Hervé This have on what molecular gastronomy is and/or should be. Whereas This wants the help of cooking schools to test his précisions, McGee is more reluctant: “I’m not sure I’d spend so much time studying misunderstandings of the past”.

(picture from Science, Credit: Ppierre Beachemin/ITHQ)