It should come as no surprise that food, chemistry and mathematics meet in baking. For once I will leave the chemistry aside for a while and turn to the mathematical aspects of baking. More precisely I will delve into geometrical problems encountered in baking. When cutting cookies from a rolled out dough or placing cookies on a sheet for baking you actually attempt to solve a mathematical problem known as a packing problem. The purpose is to maximize the distance between the cookies and maximize the size of the cookies, paying attention that the cookies should not touch. Many will perhaps start with a square packing (see below), but soon figure out that a hexagonal packing will fit even more cookies onto the rolled out dough or onto the baking sheet (especially when the dough/sheet is large compared to the cookies). The optimum way of placing 2-17 circles in a square are shown below (and the solution for up to 10.000 circles is also available).

My challenge for you however is a different one as I’m interested in eliminating the leftover dough when cutting cookies. To achieve this the cookies cannot be circular. Using a square cookie cutter (or simply a knife) would be the easiest way to leave no gaps, but how cool are square cookies? What I’m really looking for are cookie tessallations which are aesthetically pleasing, and at the same time transferable to a baking sheet. Oh yeah: a tessallation “is the process of creating a two-dimensional plane using the repetition of a geometric shape with no overlaps and no gap” according to Wikipedia. So – no gaps – no leftover cookie dough!

Should you ever want to place circular cookies on a square baking sheet, this is how to maximize the size of the cookies! (Illustrations CC-BY-SA by Toby Hudson)

This is one way of solving the problem with leftover dough shown in the top picture. A tree can quite easily be transformed into a shape that fills the plane without any gaps. This image was made using the Tess software mentioned below.

Tessellations are frequently encountered in the art of M. C. Escher, and his Regular Division of the Plane Drawings are all based on tessellations. Most of Escher’s drawings however are not useful for making cookies because they are too interlocking – it would be impossible to take the cookies apart and transfer them to the baking sheet (and baking them “interlocked” would not be an option as cookie dough inevitably will raise/expand a little, making everything stick together). But I did find one example of an Escher inspired cookie cutter as well as some other nice examples of cookie cutters especially designed to make tessellations:

Over at Thingiverse the design file for this Escher inspired cookie cutter can be downloaded (Photo by Bas Pijls via Thingiverse). And should you want to transfer your own designs into a 3D printable format, check out this cookie-cutter-generator.

From Cox & Cox you can buy this Jigsaw cookie cutter (Photo from Cox & Cox product page). If you have access to a 3D printer you can also print your own jigsaw cookie cutter.

These elaborate cookie cutters are designed by Keith Kritselis. Over at Kickstarter you can find more information about his special cookie cutters for Halloween and Christmas. What makes them special is that each tessellation is made up of three or four different shapes.

If you rather want to make your own tessellations there are a couple of different software and online apps available, but I’ve found Tess to be one of the best. An evaluation copy of Tess (no save function) can be downloaded for free. Below are a couple of designs I’ve made. The patterns are nice, but would I want to each cookies with these shapes?

And finally the challenge for you all: Make your own cookie tessallations and share it! It’s not a competition, but rather an invitation to contribute. If the design is great I might have it 3D printed on a friends MakerBot or order it in metal from Shapeways and blog about it here If you send me a picture (preferably at least 620 pixels wide/high, email to webmaster/a/khymos.org) I’ll put up a gallery to display the submitted designs.

In case you didn’t know the current world record for the world’s fastest ice cream is 10.34 seconds! To obtain the record you have to make one liter of ice cream from milk, sugar and flavoring (no eggs). Liquid nitrogen is used to rapidly cool and freeze the ice cream mixture. The current record was achieved by Andrew Ross (UK) at Cliffe Cottage in Sheffield,​ South Yorkshire,​ UK, on 6 June 2010. Prior to that the world record belonged to Peter Barham who in 2005 shaved two seconds of his previous record, ending at 18.78 seconds. To conclude his presentation on how food can be used to make students interested in physics and chemistry Peter decided to beat the current world record. Here’s a video of how it went:

Want to read more about the history of liquid nitrogen ice cream and find recipes? Then you should visit the webpages of The institute for liquid nitrogen ice cream experimental studies!

Peter Barham’s presentation at the MG seminar in Copenhagen focused on how food can be used to make students interested in physics and chemistry (not a bad thing, especially since 2011 is the International Year of Chemistry) -Most people think science is boring and difficult, he said. But demos can help bring science to life, and believe it or not – experiments are much better when they go wrong. Using balloons, champagne, potatoes and liquid nitrogen Peter Barham proved his point. As an example he asked the audience how much air weighs. He first filled a balloon with a few milliliters of water, then squeezed out all the air, tied a knot and heated the water in the microwave until all had evaporated. The first balloon exploded since he used to much water (this shows that water expands when boiled and that balloons are not infinitely stretchable!). Using a little less water for the second balloon, everything worked fine. Assuming that steam has approximately the same density as air, the size of the balloon can be measured and from this the weight of air be calculated. One finds that the volume of the water increases by a factor of approximately 800x.

There will be more foam when champagne is poured into a dirty glass due to more nucleation sites providing the dissolved carbon dioxide with more escape routes.

Ever heard about how a spoon in the neck of an opened champagne bottle can keep the champagne fizzy? Well unfortunately this is a kitchen myth. The only thing that helps is keeping the bottle cold. The spoon has no effect whatsoever. And the balloon once cooled can help illustrate this. When all the steam had condensed there was a significant amount of gas left in the balloon (remember that all the air was squeezed out to start with). This illustrates that gases are soluble in water at low temperature, but not at higher temperature. When water is boiled the gas escapes. Gas (and in particular carbon dioxide) is more soluble at lower temperatures, and that is the explanation why champagne may retain quite a lot of the fizz if stored cold. The spoon is only there to confuse you!

How long does it take to boil a potato?

Next question was: How long does it take to boil potatoes? Since the visual appearance of a potato changes around 60 °C it is possible to monitor heat transfer by simply slicing a potato in two. If boiled in water a nice ring with a slightly darker color indicates how the heat travels uniformely towards the center. If you plot the width of the ring against the square root of the time you get a nice straigth line. However, if heated in a microwave a different pattern emerges. The wavelength of microwaves is on the order of several centimeters and as a consequence the distance between hot and cold areas are about 2 cm. Slicing a microwaved potato shows how only one side has been heated. This is the simple reason why food heated in a microwave oven must be left to stand for a while to allow the heat to diffuse.

When heated in boiling water the heat travels uniformly towards the center of the potato as evidenced by the “ring” that occurs once the temperature reaches 60 °C.

When heated in a microwave there will be hot and cold areas as illustrated with this potato.

Peter Barham also mentioned the experiment that demonstrates the difference between taste and aroma. If you close your eyes, hold your nose and have a friend give you either a piece of apple or pear, you’ll have a difficult task saying which is which. But the second you let go of your nose you recognize what you have in your mouth. The experiment can also be conducted with lemon and lime or other fruit pairs with similar textures. The reason for this is that when you hold your nose, hardly any air from the mouth will enter your nose through the retronasal passage. As a result you will not be able to “smell” what’s in your mouth. But the second you let go of your nose, air can pass freely and you immediately smell what’s in your mouth. This is also the reason why the aroma of food is subdued if you have a cold and a runny nose.

Close your eyes, hold your nose and experience the difference between taste and smell! Apples and pears taste remarkably similar when the aroma is blocked out by holding your nose.

Peter’s last demonstration was liquid nitrogen ice cream and an attempt to break the current world record of 10.34 seconds. More on that in the next post

Sample #4: Precious instant coffee with hot and freezing milk. My favorite!

As part of the molecular gastronomy seminar in Copenhagen a group of food science students and aspiring chefs who meet regularily in Gastronomisk legestue (= gastronomic playroom) gave a short presentation of their work. With a yearly budget of €660 and no scientific or commercial obligations the goal is to let science and craft meet in order to foster culinary creativity. There are many notable chef-scientist collaborations in the realms of molecular gastronomy and modernist cuisine, but this is the first time I’ve heard about an initiative that establishes a dialogue between scientists and chefs while they are still students. Molecular gastronomy will always be an interdisciplinary field and what better way to encourage such a collaboration than in a “playroom”? The students are allowed to use course labs at Copenhagen University, and in return they are asked to do a least one event each year – in 2010 they contributed to Kulturnatten (= Culture night). I admire the initiative and I encouraged Mathias Skovmand-Larsen, one of the founders, to start blogging so the rest of the world can take part in their experiments. Their presentation included 4 samples for the audience to taste. My favorite was the coffee with hot and freezing milk topped with freeze dried coffee. And this was not any freeze dried coffee – it was very good coffee from the Coffee Collective in Copenhagen prepared with an Aeropress and then freeze dried! The freezing milk was in the form of ice cream. Very delicious!

Mathias Skovmand-Larsen holding a glass of sample #1: Birchwood sap and distilled amber. Interesting taste, but only as a base for something more.

Sample #3: Chicken under pressure and horseradish. The chicken had been treated (and sterilized) at 6000 bar. Compared with the pressure treated seafood at The Flemish Primitives in 2010 which retained a very raw character the appearance and texture of the chicken was more like cooked chicken.

Sample #2: Lumbsucker eggs and crispy full grain bread, designed for maximum texture contrast.

Cheeseburger in hydrochloric acid

Do ice cubes made with heavy water float or sink?

Exotic ways to cut through butter

Spectacular ways of destroying pumpkins for Halloween

Tea chemistry

See Martyn Poliakoff boil an egg

(Martyn mentions that the yellow color of egg yolks is due to a sulfur containing compound, but I’m not really convinced he’s right about that. The yellow color is mainly due to a group of chemical compounds called xanthophylls which have long conjugated double bond systems that absorb light. And BTW – if you want to dissolve the egg shell in your own kitchen: skip the hydrochloric acid and use vinegar instead.)

Baking a cake in the lab with akward equipment…

… and then figuring out what to do with the cake
(it wasn’t eaten since it was made in a chemical lab)

Mirror images: Carraway and spearmint

Fun chemistry with Crispy creme eggs

Chocolate and roses for Valentines day

As the name suggests, the TGIF posts are a little less serious than what I otherwise post here at Khymos. I hope you enjoy it

Food Geeks: Liking to eat is one thing, but becoming really familiar with the exact time and water temperature to cook the perfect soft-boiled egg? … This elevates hunger to a seriously geeky level…

I kind of feel a finger pointing at me But believe it or not, there were more than 30.000 who visited the page Towards the perfect soft boiled egg last year (and it was first published in April), so my dear fellow food geek reading this: You are not alone!

A while ago I came across the article “Christmas gingerbread (Lebkuchen) and Christmas cheer–review of the potential role of mood elevating amphetamine-like compounds formed in vivo and in furno” (abstract from NCBI, free full text pdf download from publisher). The paper reviews a hypothesis proposed by Alexander Shulgin in a series of papers appearing in Nature in the 60′s. Shulgin noted that allylbenzenes and propenylbenzens found in many spices are “merely lacking ammonia to become amphetamines”. The author reviews the evidence that such substances may be converted in the body to psychoactive metabolites, but concludes that the evidence is equivocal at best. However, the author launches an alternative theory:

“… the formation of these compounds during the cooking process, what I have called “in furno.” Examination of the Lebkuchen recipe in Table 3 reveals chemical constituents that, when heated together in furno might plausibly result in some ammonia addition to the alkenylbenzene double bonds, which would lead to the presence in the Lebkuchen of 4-methoxyamphetamine (PMA) from (E)-anethole and 4-hydroxy-3-methoxyamphetamine (HMA) from eugenol.”

But as the author prudently add: “Until the appropriate laboratory and clinical investigations are performed, it is merely a subject of speculation and fantasy.” Nevertheless is an entertaining paper to read, and I’m sure that this kind of “science triva” can cheer up discussions around the dinner tables in an otherwise dark December. And I must add that I really love the term in furno (i.e. in the oven, during the cooking/baking process) used alongside the more common in vivo and in vitro.

I’ve illustrated the proposed reactions in the scheme below. Anethole and eugenol are found in cloves/cinnamon and anise seeds respectively. Baker’s ammonia is known to chemists as ammonium carbonate, but also under names such as salt of hartshorn. It has a very strong smell of ammonia and upon heating it decomposes and releases ammonia which could possibly react with the allyl/propenyl groups.

[Found via the very funny NCBI ROFL blog]

If Richard Wiseman’s fork balancing trick is not challenging enough, why not try the fork balancing trick I did for part 8 (where I encourage experimentation in the kitchen) of my Ten tips for practical molecular gastronomy series. You only need two forks, two skewers, a wine cork and a little patience. If interested you can read more about the physics behind the balancing fork trick.

As the name suggests, the TGIF posts are a little less serious than what I otherwise post here at Khymos. I hope you enjoy it

Here at Khymos I aim to cover things related to food and chemistry, and as I stumbled over a periodic table of cupcakes (with clickable “elements” linked to recipes) I couldn’t resist to dig a little deeper. And look what I found! The periodic table of elements is iconic, but the periodic table has also become an organizing metaphor for all sorts of things, including food. The Internet database of periodic tables holds more periodic tables than you could ever dream of, but it’s not complete – at least not with regards to food. Here are the food related periodic tables that I’ve been able to find. Fun? Yes! Useful? No, not really At the end of the post I’ve also included examples of how the real periodic table of elements can be illustrated in a more or less edible fashion. All images are linked to the page where I found them. Are you aware of other periodic tables of food? Please let me know and I’ll include them in this post.

Available as a poster. HighRes available here.

Available as a poster

In case you wondered, it’s a periodic table of breakfast cereals!


HighRes flash version

Condiments that periodically go bad

Cupcakes – what else! And each “element” is linked to a recipe. Very well made!

Period table of food from Disneyland in Los Angeles (Photo: Martin Lersch). Click for a larger image.

Available as a poster

Available as a poster

Available as a poster

Available as a poster

HighRes version available

Two cropped scans available from Slashfood. Original was published in “Simple Life” fall 2006.

Available as a poster

Available as a poster

The menu at “Miracle of Science Bar & Grill” in Boston is a periodic table painted on the wall. More info at the C&EN blog. Photo: Scott Beale/Laughing Squid

Periodic table of preserves. Full resolution view available through this preview (browse to page 22 of the preview, book pages 48-49).

The real periodic table of elements represented in food
If you think fitting some kind of food into a periodic table is stretching a little too far, why not make an edible version of the real periodic table? In the process you may even learn the name of some elements

Photo by melpenguin

A nice idea for Halloween?

As the name suggests, the TGIF posts are a little less serious than what I otherwise post here at Khymos. I hope you enjoy it

The definition and use of the term molecular gastronomy has been a recurring topic here at Khymos. In my opinion no better name has been deviced, but that may actually change now. I just received an email which let me know that:

A group of influential international chefs have sequestered since yesterday in Alicia, Spain. Their mission has been to find a more palatable term for the dreaded “Molecular Gastronomy”. The consensus seems to be leaning towards ORGASMIC, an acronym for ORganoleptics, Gastronomy, Art, & Science Meet In Cuisine. A final vote on the proposed name change is scheduled for tomorrow morning, followed by the unveiling at a press conference.

Unfortunately information about which chefs have been invited to the event is scarce, so it’s difficult to judge about what impact this will have. Nevertheless, since the acronym includes so many of the different aspects related to molecular gastronomy I likely that the new name will eventually replace the term molecular gastronomy. I’ll update once I have more details!

Update: Fellow blogger Aiden Brooks is currently living in Barcelona and has many more details on this. It seems that there will actually be a new Erice meeting and that the current “secret session” is a run up to the next International Workshop on Molecular and Physical Gastronomy.