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.

A couple of books have caught my eye during the year and have naturally made their way into my Christmas wish list (and some I’ve already ordered myself). Please let me know if there are books you belive should be on this list that I have missed.

Culinary Reactions: The Everyday Chemistry of Cooking
by Simon Quellen Field
288 pages

The back cover states “When you’re cooking, you’re a chemist!”. I couldn’t agree more and figured this was a book for me. I already have my copy in front of me and see there are many interesting observations and experiments described.

Heston Blumenthal at Home
by Heston Blumenthal
408 pages

The Family Meal: Home Cooking with Ferran Adria
by Ferran Adrià
384 pages

Ferran and Heston have jumped onto the cooking-at-home-with-great-chefs waggon. They’d be more than welcome to come and cook in my kitchen, but until that happens I’ll let their books inspire me. An important thing about these books is that, given their close collaboration with scientists, I have a high expectation that the advice given in all recipes should be scientifically sound (which of course is not the case for many other cook books).

Neurogastronomy: How the Brain Creates Flavor and Why It Matters
by Gordon M. Shepherd
288 pages

I stumbled across this one by chance. It looks like a “must have” too me, and my copy is already on its way. In an interview with Salon, the author Gordon M. Shepherd, a professor of neurobiology at the Yale School of Medicine, says that:
“I began to realize that increasingly smell was for sensing the flavor of food. It goes almost unrecognized as we eat our food because we think it all comes from taste in our mouths. The more research that I did on flavor, the more I realized that the sense of smell was the dominant sense in flavor — and that we are almost totally unaware of it.”

The Oxford Companion to Beer
edited by Garrett Oliver
960 pages

Having ventured into brewing I found this book quite irresistable!

The Kitchen as Laboratory: Reflections on the Science of Food and Cooking
edited by Cesar Vega, Job Ubbink and Erik van der Linden
336 pages

I’ve mentioned this book previously. With 35 essays covering a range of topics this should be of interest to many Khymos readers!

Apart from these books we just have to face it: there’s no way around Modernist cuisine. If you don’t own a copy yet I’m quite sure it still sits there on the top of your wish list. And – if you happen to read Swedish – I would highly recommend the recently published book Matmolekyler (“Food molecules”) by Malin Sandström and Lisa Förare Winbladh (also check out their blog blog with the same name – also in Swedish).

Talking to a friend last year who is an avid home brewer made me realize how little I knew about beer and brewing. Inspired by what I learnt from the conversation I started reading Palmer’s How to brew which is essential for starters, but soon I also turned to Brigg’s Brewing – Science and practice and Priest’s Handbook of Brewing which are more rewarding if you’re a scientist. The first two steps in brewing beer – mashing and wort boiling – are really quite sophisticated extractions. And there is a lot of chemistry involved, so brewing beer seemed to me like an obvious extension of all my other interests. This is also the reason why I wanted to include a post about brewing in the Wonders of extraction series. The pictures for this blog post were taken as I brewed and bottled my latest batch, an American India Pale Ale.

Having read quite a lot about beer I soon found myself in the kitchen brewing my very first German wheat beer in August last year. I had decided that to familiarize myself with brewing I would try to brew with whatever equipment I had available in the kitchen. Mashing and lautering was done with a pasta strainer(!), and I boiled the wort in the largest pot I could find. While doing this it became very clear to me that these steps can be viewed as “reactive extractions”. Something is extracted and then something more happens! Given the simple method and equipment used I was totally amazed by the end result. And I quickly decided that this would not be my last batch of beer. After hours or reading (and making an important decision that I would like to spend my time brewing, rather than building the equipment) I finally settled with a Speidel Braumeister. This is a compact RIMS (Recirculating Infusion Mash System) type brewery system where a pump forces the wort upwards through the malt bed (different from a conventional RIMS system where the wort is allowed to drain through the malt bed by gravity). The picture below probably explains more than countless words.

The Speidel Braumeister is a compact RIMS type brewing system. During mashing a malt pipe is inserted. A metal screen and filter cloth at both ends of the malt pipe hold the malt in place. A pump forces the wort upwards through the mash (bottom left). After mashing the malt pipe is lifted out to allow the wort to drip of (bottom middle). Extra water may be added to rinse out remaining wort. The malt pipe is removed prior to the wort boiling (bottom right). Illustrations taken from www.speidel-braumeister.de

What really attracted me to brewing is that the range of ingredients available to professional brewers is also available to home brewers. And while a commercial brewery will do what it can to cut costs, opting for cheaper ingredients whenever possible, the money spent on malt, hops and yeast doesn’t really matter that much for the home brewer. As a result one can actually brew some very nice beers at home. And a much larger range of beers than is available in your next door shop. I believe this is quite different from what is the case for home brewing of wine (at least in Norway where fresh grape juice in those quantities is not available).

The extraction of sugars from malted barley is termed mashing. During mashing one utilizes the enzymes naturally present in grains to break down the starch to fermentable sugars (meaning sugars that the yeast can convert to alcohol). It sounds simple, but the process involves a number of enzymes with different temperature and pH optima. And one needs to do a couple of tricks for the enzymes to appear, so I will start with a brief introduction to malting (but feel to skip this and continue reading about mashing further down).

Malting
When a barley seed is wetted it will start to germinate. The release of the plant hormone gibberellic acid in the seed embryo sets of the synthesis of proteins capable of breaking down starch to sugar which will be needed for the seed to grow. These proteins are called enzymes, and they are extremely efficient at breaking down starch to sugar. After a couple of days the sprouted grain is air dried. As the water content decreases a second plant hormone, abscisic acid, is released. The effect is the opposite of gibberellic acid, and the synthesis of further enzymes is halted. The lowered water content also stops the enzymatic breakdown of the starch. The air dried green malt as it is now called is further kiln dried. The small amount of liberated sugar alongside the proteins allows for the Maillard reaction to proceed if the conditions are right, resulting in characteristic malt and caramel flavors as well as colors ranging from golden to brown and almost black. The darker the color of the malt, the less will be left of the enzymes required for starch hydrolysis (but this is usually not a problem as only a relatively small amount of very dark malt is used). Some enthusiasts malt their own barley, but most home brewers buy whole grain malt.

The hopper of my malt mill filled with ~5 kg malt is ready for some action (top left). As the grains pass the two rollers (bottom left) the malt is carefully crushed (bottom right). If crushed too fine the result is a “stuck mash”, if crushed too coarsely less sugar will be extracted and the yield drops.

Bottom screen and filter cloth inserted into the malt cylinder (top left) which is then lowered into the water filled brewing pot, crushed malt is then poured into the malt cylinder (top right), covered with a filter cloth (bottom left) and a metal screen (bottom right).

Mashing
The malt now contains starch as well as the enzymes required to break down the starch. When water is added and the temperature brought up to around 65-67 °C the enzymes start doing their job which is to break down the starch to sugars. This step is called mashing. Several enzymes are at play, but I’ll focus on the two most important: alpha-amylase and beta-amylase. Alpha-amylase is more temperature stable, attacks and breaks up the starch polymer at random places, resulting in smaller starch molecules known as dextrins. Only a very small fraction of the starch is converted to fermentable (= usable for the yeast) sugars by alpha-amylase. Beta-amylase on the other hand is less temperature stable but breaks down starch to maltose which is fermentable. By carefully choosing the mashing temperature the relative activity between alpha- and beta-amylase can be fine tuned. Mashing at 64-65 °C favors beta-amylase which yields a wort higher in fermentable sugars, resulting in a beer which is thinner, drier, higher in alcohol and has a lower final gravity. Mashing at 68-69 °C favors alpha-amylase which yields more dextrins which are not fermentable, resulting in a beer with more body which is sweeter, lower in alcohol and has a higher final gravity (i.e. residual “sugar” content). This may be confusing but trust me – it’s even more confusing when John Palmer tries to explain it with a garden allegory! I encourage you to check out the figure below which may help clarify things.  After mashing is complete the temperature is increased to 78 °C to inactivate the enzymes. The malt pipe is then pulled up to allow the wort contained in the malt bed to run off (termed lautering). The malt bed may be washed with 78 °C water (sparging) to increase the yield.

The wort is circulated upwards through the malt bed throughout the mashing time. At first the wort is very cloudy (top left) due to the fine particles from the crushing. The malt bed acts as a huge filter which helps remove particles, yielding a clear wort (top right). The time and temperature steps are controlled by a PID (bottom left). After mashing the malt cylinder is pulled up, the wort is allowed to run off (termed lautering) and the malt bed may be washed with water (sparging). The malt that remains is known as wet distillers grain (bottom right) and does wonders to your compost! Or you can use some of it for baking a special bread called treberbrot (named after the German word for spent grain).

If the extractable yield of a malt was 100% and the mash efficiency was 100% 1 kg malt would yield 1 kg of sugar in the mash. However, the extractable yield for a pale malt is about 80% (the hulls for instance are not extractable), and in my last brew I reached a mash efficiency of 78%. In effect I got approximately 624 g of sugar for each kg of malt.

Wort boiling
After mashing and lautering the wort is heated further and kept at a rolling boil for about one hour. There are several reasons for this. First the mashing enzymes are destroyed. Another one is to sterilize the wort (i.e. kill off unwanted bacteria and yeasts) prior to the following fermentation. Furthermore the boiling will allow some unwanted volatiles such as dimethyl sulfide to escape. The boiling will also facilitate the precipitation of proteins, resulting in a clearer beer. But perhaps most important for the resulting taste of beer is the addition of hops to the boiling wort. Hops are a kind of flowers that impart a bitter taste and in some cases also a significant aroma to beer. The bitterness balances the sweet taste of the wort, and the hops also stabilize and increase the shelf life of beer due to a mild antibiotic effect against bacteria that could otherwise ruin the beer.

Hops are typically added as whole cones or pellets as shown here. The pellets are crushed hop flowers that have been compressed for easier addition. Once added to the wort the pellets fall apart. The larger surface area of the fines results in a faster extraction of the alpha acids.

The hop cones contain alpha acids which are not particularly water soluble, and in fact not very bitter either. But when boiled they undergo a chemical change which makes them more bitter, the so called isomerization (shown below). Hops that are added for bittering of beer are typically added to the wort once it starts to boil as the extraction and isomerization processes takes some time. The extraction of alpha acids and the isomerization process are well studied and brewers can accurately predict and design the bitterness of a beer using online calculators. Required input data are wort volume, wort gravity (i.e. sugar content), alpha acid content in the hops and boil time as well as whether the hops are added as whole flowers or as fines compressed to a pellet. The hop bitterness is expressed in International Bitter Units (IBU), typically ranging from light lagers or wheat beers with 5 IBU up to India Pale Ales with 100 IBU or more. Those with access to a spectrophotometer can measure an approximate IBU of a beer by recording the absorbance at 275 nm and multiplying the number by 50 (IBU = A₂₇₅ x 50).

In addition to alpha acids hops also contain essential oils, some lighter, more volatile (primarily terpenes such as myrcene, linaol, geraniol, limonene, terpineol etc. – typically with a citrusy, green, grassy, floral aroma) as well as some heavy, less volatile oils (humulene, caryophyllene, farnesene – typically with a woody, spicy aroma). When smelling fresh hops it’s primarily the essential oils that make up the aroma. The majority of volatiles are lost from the boiling wort due to evaporation. However, if hops are added towards the end of the boil the less volatile oils will remain in the wort and in the resulting beer and impart a significant hop aroma to the beer (not to be confused with the bitter taste which results from prolonged boiling of hops). In some cases hops are even added to the wort during of after fermentation, so called dry hopping. This allows the extraction of the lighter volatile essential oils in the hops. In order to capture the lightest volatile oils it’s important to use fresh hops (i.e. hops that have not been dried). To complicate matters further many of these essential oils are quite reactive towards oxygen, and if digging deeper into the molecules behind a “hoppy” aroma one will find several oxidation products of the essential oils.

Here I should add that chefs probably could learn something from the early and late addition of hops to the boiling wort. I have a feeling that the early vs. late addition of spices and herbs has not yet been explored sufficiently. And just like the same hop contributes different “fractions” of its flavor depending on when it is added I also think that spices and herbs could contribute a broader range of aromas if they were not added all at once. I would be very interested in hearing your opinions on this! And hereby I also share an idea for a nice science project: Boil herbs/spices, take samples regularly and see how concentration changes with time. When does it reach a maximum? This would be very useful information for chefs!

The wort is boiled (top left) for several reasons, one is to extract and isomerize alpha-acids from hop cones into iso-alpha-acid which provide the important bitterness to beer. After boiling cold water is passed through a copper spiral (top right) to rapidly cool the wort (bottom left). After cooling the gravity (i.e. density) of the wort may be measured with a hydrometer (bottom right).

Towards the end of the wort boil some brewers also add some Irish moss to help clarify the wort. Interestingly this moss should be well known to the readers of Khymos, albeit in a slightly different form – namely as a white powder sold under the name carrageenan!

Dry Irish moss contains more than 50% of the polysaccharide carrageenan. When used in brewing the moss is wetted and allowed to hydrate before it is added added to the boiling worth the last 10-15 min.

The rest of the brewing process does not involve extractions, and hence is not the main focus of this blog post. But I’ve included some pictures to give you an idea of the different steps:

The cooled wort is sprinkled (top left) into the fermentation bucket to expose it to oxygen. For extra oxygenation an aquarium air pump can also be used to aerate the wort, resulting in some foam (bottom left). The added oxygen allows the approximately 100 billion yeast cells (top right) to grow/multiply before they move into anaerobic mode to produce ethanol from the wort sugars (primarily maltose). Proteins and hop residues are carefully left behind in the boiling vessel (bottom right).

Clean bottles are covered with aluminum foil prior to dry sterilization (top left). The fermented (and in this case dry hopped wort) is siphoned (top right) into a second bucket where it is mixed with the priming sugar need for bottle carbonation. The bottling device used here (bottom left) has a small valve which only opens once the bottom of the bottle presses against it, thereby reducing foaming during bottling. Labels are glued onto the bottles with milk.

After a minimum of 1-2 weeks bottle fermentation the American India Pale Ale is sufficiently carbonated for the very first tasting!

Previous blog posts on the Wonders of Extraction
Wonders of extraction: Water
Wonders of extraction: Ethanol
Wonders of extraction: Oil
Wonders of extraction: Espresso (part I) (sorry – no part II yet…)
Wonders of extraction: Pressure

A book I’ve been looking forward to for a long time is The Kitchen as Laboratory: Reflections on the Science of Food and Cooking. It is now available for pre-order with expected delivery on January 31st, 2012. Work on the book began back in 2008, and that year coincidentally marked the 20th anniversary of But the crackling is superb, a refreshing anthology on the science of cooking and eating edited by Nicholas and Giana Kurti. The editors of The Kitchen as Laboratory, Cesar Vega Morales, Job Ubbink and Erik van van der Linden, wanted to continue in the spirit of this book. Through 35 essays the invited chefs, scientists and cooks explore topics of their choice, often based on experiments in their own kitchen. This includes a contribution by me on the Maillard reaction and how we – often without thinking about it – increase it’s rate in different ways when cooking. As for the other contributions, based on the preliminary lists all I can say is that I look forward to read the book!

The book Cooking science – Condensed matter by Adria Vicenc came out last year, but only recently did it appear on my radar. This 75 page preview suggests that it is part coffee table book and part documentation of modern Catalan cuisine combined with short essays on various topics such as food preservation and synaesthetic cooking. Add to that a dash of technology and large photos and descriptions of a sous vide water bath, a rotary evaporator, a freeze drier etc. It’s kind of like a light version of Modernist Cuisine. In his introduction Ferran Adria states that: “As has happened throughout history in the majority of the stages of human evolution, the new technologies act as a support for the progress of cookery”. This is technology with a purpose: better food!

More information in Catalan, Spanish and English is available from the Materia Condensa website. The book features QR codes which lead to various digital resources (also available directly from the website).

The book features a periodic table of preserves (full resolution view available through this preview) which I’ve now added to my list of other food related periodic tables. Fun? Yes! Useful? Probably not…

Readers well aquianted with the food blogosphere will likely be familiar with Aki Kamozawa and Alex Talbot’s blog Ideas in food. Since December 2004 they have generously shared pictures, ideas, insights and inspirations online. As chefs they have eagerly integrated modernist techniques and elements in their cooking, allowing technology to improve their cooking whenever possible. No wonder I’ve been a long time follower of their blog! And needless to say I was also exicted to receive a review copy of their recent book Ideas in food: Great recipes and why they work.

First and foremost the book is a great collection of ideas explored by the authors. The ideas are exemplified through recipes (about 100 in total) which showcase the creativity of the authors, from the simple vanilla salt to innovative pasta and risotto techniques, red cabbage kimchi with a built in pH indicator, grilled potato ice cream and practical examples of how hydrocolloids can be utilized. It is certainly an engaging book, and my copy is filled with countless comments, “Try this!”, “Interesting!” and enthusiastic exlamations, but also question marks and disagreement. For some reason the book has been divied into Ideas for everyone and Ideas for professionals, the latter dealing mainly with hydrocolloids. But why the discussion of starch and gelation is reserved for the professionals whereas the recipe for homemade mozarella which calls for lipase, citric acid and rennet is placed in the “for everyone” section, eludes me.

I suggest you have a pencil ready when reading the book!

As the title suggests there are not only ideas and recipes, but also exlanations that sometimes dig deep into food science. The real strength of the book are the cases where a deeper understanding of the underlying science leads to new ideas. Having explored potatoes and hydration of starch, a simple yet brilliant idea which comes out of this is the parcooked rice (65 °C for 30 min) which subsequentially allows for a superfast risotto. As elegant is the hydration of dried pasta by soaking in cold water. Once hydrated, the pasta is drained and kept in a closed container/bag in the fridge. When dropped into boiling water the pasta will cook as fast as fresh pasta. Combining this with other ideas led to a mac’n cheese made from roasted pasta that is smoked and then hydrated in milk, reserving the excess milk with the surface starch for later stage to help thicken the sauce.

Pasta hydrates in cold water (1:4 ratio of pasta to water) within a couple of hours. The fully hydrated pasta cooks within a couple of minutes.

Explaining the science of food and cooking in lay terms is difficult, especially when striving for simple and correct explanations. On some occasions the authors strike a good balance here, but at times the explanations are either too simplistic or too detailed to be of any real help. I was often left with a feeling that the text desperately called for illustrations for the reader to properly grasp the concepts, for instance in their discussion of amylopectin, amylose and starch granules. Perhaps it’s because I’m used to science text books, but the fact that Ideas in food doesn’t have a single figure, diagram or photo is a drawback in my opnion.

Understanding how amylose and amylpection would be easier had they included a simple drawing like this one.

Ever since reading Hervé This’ book Révélations gastronomiques (available in German as Kulinarische Geheimnisse, not available in English) I have appreciated the approach that combines recipes with answers to the many whys that pop up in my mind. Comparing Ideas in food: Great recipes and why they work with This’ book, what shines through at places is the author’s lack of scientific training. Without doubt they know much more food science than the average chef, but it is surprising for instance that the Maillard reaction is not mentioned in their discussion of stocks. And the precision of the recipes is often questionable, especially regarding their use of metric units in the first section. Saying that 1/2 cup of milk equals 130 grams makes sense to me because I expect to see a rounded number. But an online conversion calculator I often use says that for milk 0.5 US cups = 121.8 g = 118.3 ml, so I would naturally have rounded this to 120 grams. On the other hand, when the authors state that 8 3/4 cups of water equals 1968.75 grams the precision implied by the number of digits will make for a good laugh for scientists reading this. And I’m puzzled by how the “cups” used apparantly range from 225 to 260 mL – is there something I’m missing here?. The ultimate solution to this of course would be to eliminate the United States customary units alltogether (sorry all Americans!). Ironically this is exactly what the authors did in the “Ideas for professionals” section.

In the light of the recent paper on the 6X °C egg the whole chapter on “perfect” eggs seems a little outdated. The recipes are probably fine (I haven’t tested them), but I was surprised to read that egg whites coagulate from 60-65.5 °C (this must be a typo) whereas egg yolks coagulate from 65-70 °C (true, but they start to coagulate at a lower temperature, and it’s a function of time and temperature).

To conclude, the compilation of great food ideas is what I found most rewarding in the book. And despite the shortcomings mentioned above I would wholeheartedly recommend the book, simply because of all the nice examples of how a new technique or theoretical insight can be extrapolated into related areas and lead to new ideas in the kitchen. I suggest that you get Ideas in food: Great recipes and why they work for it’s collection of ideas and the creativity of the chefs. But if you’re interested in the whys of cooking you will be better served by other books, the obvious choices being On food and cooking and Keys to good cooking by Harold McGee or The science of cooking by Peter Barham.

Ideas in food – Great recipes and why they work
Aki Kamozawa and Alexander Talbot
320 p, no illustrations/photos
2010, Clarkson Potter
ISBN 978-0-307-71740-5

Very sturdy box-in-box packaging with special deformation elements lining the inner box. You’ve probably guessed it by now…

My copy of Modernist Cuisine has arrived!

If you’re a scientist and like to cook these books are a must! Actually… if you’re serious about cooking I’d say you have no choice!

A first observation is that I need to have a notebook nearby when sitting down with the books. Leafing through the volumes there are so many things I want to try and ideas start popping up. And with >2400 pages it may take some time before I accidentally return to the exact same page

The lecture schedule for the 2011 fall semester is as follows (exact dates and locations here):

1. Historical Context and Demos Illustrating the Relationship of Food and Science. Speakers: Dave Arnold (Food Arts magazine’s Contributing Editor for Equipment & Food Science), Harold McGee (author of On Food and Cooking: The Science and Lore of the Kitchen and columnist for The New York Times) and David Weitz (Mallinckrodt Professor of Physics and of Applied Physics at Harvard)
2. Sous-vide Cooking: Phases of Matter. Speaker: Joan Roca (El Celler de Can Roca).
3. Heat and Temperature Flux in Chocolate. Speaker: Ramon Morató (Aula Chocovic)
4. Viscosity and Thickeners. Speaker: Carles Tejedor (Via Veneto), Fina Puigdevall and Pere Planagumà (les Coles)
5. Food Texture and Mouth Feel. Speaker: Grant Achatz (Alinea)
6. Gelation. Speaker: José Andrés (ThinkFoodGroup, minibar, Jaleo).
7. Emulsions: Traditional and New Emulsions. Speaker: Nandu Jubany (Can Jubany) and Carles Gaig (Fonda Gaig).
8. Proteins & Enzymes: Transglutaminase. Speaker: Wylie Dufresne (wd~50).
9. Browning Reactions: Culinary Examples. Speaker: Carme Ruscalleda (Sant Pau, Sant Pau de Tòquio).
10. Molecular Differences Between Production Methods. Speaker: Dan Barber (Blue Hill).
11. (Title to Come) Speaker: David Chang (momofuku)
12. Heat Transfer. Speaker: Nathan Myhrvold (former Microsoft CTO; co-founder and CEO of Intellectual Ventures; and author of Modernist Cuisine: The Art and Science of Cooking)
13. Dessert. Speaker: Bill Yosses (White House)
14. Technology and Cooking. Speaker: Ferran Adrià (elBulli)

Below is the 2010 schedule for comparison. Remember that all of these are available on Youtube and iTunes!

1. Science and Cooking: A Dialogue. Speakers: Harold McGee, Ferran Adria (elBulli), José Andrés (minibar by josé andrés, Jaleo, The Bazaar) with commentary/moderation from Professors David Weitz and Michael Brenner (Harvard).
2. Sous-vide Cooking: a State of Matter. Speaker: Joan Roca (El Celler de Can Roca).
3. Brain Candy: How Desserts Slow the Passage of Time. Speaker: Bill Yosses (White House Pastry Chef).
4. Olive Oil & Viscosity. Speaker: Carles Tejedor (Via Veneto).
5. Heat, Temperature, & Chocolate. Speaker: Enric Rovira.
6. Reinventing Food Texture & Flavor. Speaker: Grant Achatz (Alinea).
7. Emulsions: Concept of Stabilizing Oil &Water. Speaker: Nandu Jubany (Can Jubany).
8. Gelation. José Andrés (ThinkFoodGroup, minibar, Jaleo).
9. Browning & Oxidations. Carme Ruscalleda (Sant Pau, Sant Pau de Tòquio).
10. Meat Glue Mania. Wylie Dufresne (wd~50).
11. Cultivating Flavor: A Recipe for the Recipe. Dan Barber (Blue Hill).
12. Creative Ceilings: How We Use Errors, Failure and Physical Limitations as Catalysts for Culinary Innovation. David Chang (momofuku).

For a book about food this is a rather unusual book. The author states in the preface that the goal of the book is to “point out new ways of thinking about the tools” that are found in the kitchen. It’s not a book you’ll pick up for its recipes, even though the 100+ recipes included are fine. And it’s not a book you would pick up because of mouthwatering photographs of food. It is however a book that could trigger a lifelong interest in cooking among those who are scientifically minded. Where an experienced chef can read between the lines of a recipe, the rest of us can turn to books like Cooking for geeks to get hints on how to turn a recipe into a tasty dish.

The book is filled with advice ranging from the obvious (when straining pasta, pour the boiling water away from you) to the interesting and brilliant, such as the best way of cracking an egg. My experience from working in a shared lab is that you can learn a lot from observing how your colleagues work in the lab. A kitchen is not too different from a lab, and Potter has done a good job capturing small, trivial and “obvious” details, the tricks of the trade. For an inexperienced cook the obvious is often the best place to start, and it’s a good thing the author dares to include this kind of advice.

Following tips on kitchen tools and gadgets, how to pick a recipe, how to organize the kitchen and how to calibrate equipment, the book focuses on the basics of flavor. But where many science books leave it with descriptive text about taste and smell, Potter goes on to propose experiments to try out in the kitchen. And the systematic and analytical mind of the authors shines through when he lists typical bitter, salty, sour, sweet, umami and hot ingredients from different regional cuisines.

The chapter which may have the greatest potential of improving your cooking, covers time, temperature and cooking methods. Depending on the meat used the denaturation of proteins occurs at different temperatures. That’s why it’s important to know at which temperature you cook. Combine this with different methods of heat transfer (conduction, convection, radiation) and varying rates of heat transfer in foods, and you’re left with a complex set of equations to solve in order to obtain a steak with a nicely browned surface, an outer layer which is not overcooked and a core with the desired doneness. Luckily there are easy ways to achieve this, and the book includes an introduction to sous vide cooking and the hardware needed for this. Using temperature controlled water baths (not unlike the ones used in chemistry labs), meat is sealed in plastic bags and cooked at the desired core temperature, thereby avoiding heat gradients all together. For better flavor, a quick browning is recommended to get the Maillard reaction going.

The chapter “Playing with chemicals” may frighten the average consumer, but certainly warms the heart of chemist who is well aware of the many pure chemicals and polymers found in the kitchen. Sugar, salt, acids and bases are well known, hydrocolloids perhaps less so. But they are even more fun to play around with. Ranging from well known starch and gelatin to more exotic gelling agents such as agar, carrageenan and sodium alginate to mention a few, Potter explains the science and gives practical tips on how to succeed with the recipes.

In between the many fact boxes, recipes and tables there are also more than 20 interviews with scientists, food professionals, and bloggers to be found. Again, not very common for a cook book, but it fits in nicely with all the other bits of information. At this point I should also mention (in the interest of full disclosure) that as a food blogger I was one of the lucky persons to be interviewed for the book.

Jeff working on an ice cream maker made with Legos. (Photo © 2009 Atof Inc.)

Jeff Potter is a computer scientist and makes no attempt at hiding this in the book, for instance when he wants to overclock an oven to make a perfect pizza. The book is strewn with “hacker lingo”, and what some may term a good sense of humor others frown at as geeky jokes and unnecessary references to software engineering. In my opinion the book could have reached an even greater audience without the references to computer science. Apart from this my main objection against the book is the lack of color photos, and the minuscule size of the b/w photos. Some of the pictures are available in color and high resolution through flickr.com though, and the author also encourages users to post pictures tagged with “cookingforgeeks” at the same site.

Despite these objections it is a well researched book, and the wide range of topics and the number of fun facts, hacks and tips is amazing. Jeff Potter succeeds in bringing popular food science to a broad audience, and I’m convinced that the book could even find its place in science education and as a source of inspiration for science projects. The book also encourages a work methodology that is familiar to every chemists: experiment and observation. This is obvious in the lab, but just as useful in the kitchen. And in case you’re still curious about the eggs: Crack them on a flat surface. This will result in larger pieces that aren’t pushed into the egg. Since I read this tip I’ve tried it several times, and it works very well!

Review by Martin Lersch
Based in Norway, organic chemist Martin Lersch blogs about food and chemistry at Khymos (blog.khymos.org) besides his day time work in R&D at a biorefinery.

Copyright Nature Chemistry. This review was first published in Nature Chemistry as “Kitchen hacks for better cooking” (Lersch, M. Nature Chemistry 2010, 1001. DOI: 10.1038/nchem.879).

Cooking for Geeks
by Jeff Potter
O’REILLY MEDIA: 2010.
432 pp. $34.99

It came as no big surprise that NOMA defended its no. 1 position in April. A lot of the press coverage of NOMA and René Redzepi focuses on foraging (some even claim that we are in The Era of the ‘I Foraged With René Redzepi Piece’). It is all about nature and natural ingredients. Many would probably claim that NOMA is as far away from molecular gastronomy and science as you could possibly come. In March René Redzepi attended The Flemish Primitives in Oostende. I was there, and the one question I asked René at the press conference was this:

ML: The Flemish Primitives aims to bring together chefs, scientists and artists. There is also a co-operation between Noma and the University of Copenhagen. What have you learnt from from working with scientists?

RR: A lot! A lot! There is an incredible amount of knowledge to be gathered. Chefs are caretakers of flavor whereas scientists care about why things happen. But they don’t care about flavor. Torsten Vildgaard, one of my chefs, has been working 4 months every year on the project at Copenhagen University.

In a recent interview with WSJ René also said that “a lot of the techniques developed during the molecular phase have now been incorporated even into our style of cuisine because of their practicality”. I find it very fascinating and reassuring that René sees no contradiction between a modern approach to cooking, utilizing science and technology for what it’s worth, on the one side and his own cooking on the other. He is truly open minded and lets modern equipment and techniques coexist with his foraging approach.

During the interview René also mentioned the Nordic food lab, a non-profit organization founded by René Redzepi and Claus Meyer that aims to scientifically explore the New Nordic Cuisine (manifesto, 40-page booklet). They promote open sharing of their results, and contrary to food research in universities the Nordic food lab is “committed to show tangible results on a more frequent basis and on a slightly lower academic level than would be expected from e.g. a university.” I really recommend checking out their news section (which is more or less in a blog format – unfortunately I could find any funtioning RSS link on the page, but http://www.nordicfoodlab.com/feed seems to work!)

Of course René also talked about other stuff than food science and molecular gastronomy. One thing that he’s particularily focused on now is the new food festival MAD foodcamp (MAD is “food” in Danish). It takes place on August 27 & 28 (the last two days of the Copenhagen Cooking festival). The topic this year will be vegetation, there will of course be chef & food, but there is also an International symposium and they have announced that Harold McGee is coming! René mentioned that the most challenging part is in fact to find writers and scientists who want to contribute to the symposium.