Harold McGee, author of the seminal On food and cooking: The science and lore of the kitchen (which is one of my favorite non-recipe books for the kitchen) has done it again! The book Keys to Good Cooking: A Guide to Making the Best of Foods and Recipes is to appear in October, but is already available for pre-order as I write. The book is one step closer to the kitchen and the actual cooking than On food and cooking. In a mini Q&A with NY Times in 2008 Harold McGee said the following:

“I’ve heard from many cooks that while they value the scope and depth of “On Food & Cooking,” when they need practical help with a specific technique or ingredient it’s often hard for them to locate the information. So my next book will be nothing but practical information and directions, concise and brief.”

I think it’s fair to say that Harold McGee, more than any other person I know of, has been very successful at distilling scientific work into a very readable and accessible form. He did this back in 1984 with the first edition of On food and cooking, and then again in 2004 with a more or less rewritten edition in 2004. A complete book with practical information rooted in science can easily become the single most useful book in your kitchen!

When I wrote about Nathan Myhrvold’s book project in November he estimated the book to reach 1500 pages. But what originally started out as a 300-page book on sous vide has now, with the help of a 20-person team, grown to a total of 2200 pages spanning five volumes! Need I say more? Finally the long wait is over: The Modernist Cuisine: The Art and Science of Cooking is now available for pre-order at Amazon, and the expected release date is December 1st. One could almost be afraid that there will not be anything more to blog about here at Khymos as everything will be covered in Modernist Cuisine (but I know better – every previous talk about “end of science” has turned out to be more a starting point than a final destination)

Ferran Adrià says that “This book will change the way we understand the kitchen”, and according to Heston Blumenthal it’s “A fascinating overview of the techniques of modern gastronomy”. And if that’s not enough – take a look at this 26 minute video which guides you through the almost endless amount of high-tech equipment Nathan Myhrvold and his team have available. Oh boy, oh boy!

Other links:
The lecture “Cooking in Silico: Understanding heat transfer in the modern kitchen” by Nathan Myhrvold and Chris Young is available for streaming/download from University of Washington.

I just received an alert today about a major review article on molecular gastronomy: Molecular Gastronomy: A New Emerging Scientific Discipline (DOI: 10.1021/cr900105w) is a British-Danish joint publication by Peter Barham, Leif H. Skibsted, Wender L. P. Bredie, Michael Bom Frøst, Per Møller, Jens Risbo, Pia Snitkjær, and Louise Mørch Mortensen. Peter Barham is a professor in polymer physics at the University of Bristol, author of The science of cooking and probably doesn’t need further introduction. The Danes are all associated with the Department of Food Science at the University of Copenhagen and have a varied background in chemistry, food science, sensory science and psychology background. Check out the links to their individual profiles more info on projects and publications. Leif H. Skibsted and Michael Bom Frøst head several molecular gastronomy related projects. The Danish scientists also work closely together with Claus Meyer, chef at Meyers madhus and visiting professor at Copenhagen University, and Torsten Vildgaard, assistant head chef at Denmark’s gastronomic shining star Noma (which Claus Meyer started together with René Redzepi in 2004 – they were ranked 3rd in Restaurant magazines top 50 list for 2009, only surpassed by el Bulli and The Fat Duck).

Considering the impact factor of Chemical Reviews (ranked as a clear no. 1 among chemistry journals), this review will likely remain the review on molecular gastronomy for years to come – so you can just as well go ahead and read it. It’s got a whopping 53 pages and more than 350 references, and will be very useful for further studies and research. Oh, and the authors have opted for sponsored access, meaning that you can download the whole review for free!

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Some curiosa as a post scriptum: Even though the above mentioned review is the most comprehensive academic treatment on molecular gastronomy to this date, the very first mention of “molecular gastronomy” in Chemical Reviews was in a review on platinum chemistry in 2005 (check out the full text search). When writing a review on platinum C-H activation chemistry some years ago with my supervisor I mentioned in the short author bio that besides my research activities I had “a strong interest in molecular gastronomy”. My supervisor prof. Mats Tilset then added to his bio that he had “a strong interest in practical gastronomy”. Even in serious journals there is room for a little fun

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

Nathan Myhrvold giving a TED talk about some of his many interest (click image to see video). Photo by Neil Hunt from flickr.com (CC BY-NC 2.0).

If you’ve played around with sous vide cooking there’s a good chance that you’ve visited the massive eGullet thread on sous vide (currently spanning more than 100 pages and 3000 posts), and in that case you’ll be familiar with Nathan’s many well informed posts on sous vide. There have been rumours about an upcoming book for quite some time, and things are getting more and more exciting. The last I heard was that he had a team of 5 people working on a book about sous-vide. This has now increased to a team of 15 people, including 5 professional chefs, a photographer, an art director, writers and editors. And there’s more:

“The project has grown in size and scope. Originally planned as a 300-page discussion of sous vide, an increasingly popular restaurant technique of cooking food in vacuum-sealed bags in warm water baths, the book has swelled to 1,500 pages that will also cover microbiology, food safety, the physics of heat transfer on the stove and in the oven, formulas for turning fruit and vegetable juices into gels, and more.”

Wow! Let’s hope that Nathan’s “one year left” statement is actually true this time. I’m really looking forward to see this book!

In New York the Experimental Cuisine Collective has been arranging regular seminars since 2007, in Paris Hervé This’ monthly seminar has been running for many years – and now finally the London Gastronomy Seminars are about to launch. To their upcoming event on November 30th they have invited Hervé This, Tony Conigliaro and John Forbes to speak about on Flavor extraction. You might remember that I’ve blogged about the wonders of extraction here previously (focusing on water, ethanol, oil and more specifically on espresso and walnut liqueur) – it’s a really fascinating topic and I wish I could take part in the seminar! If you’re in London or live nearby I would strongly recommend you to visit the seminar

After 7 days of feeding my sour dough starter “took off” and was ready for baking. Even with a water bath set to 28 °C it took longer than expected. I started off with 100% hydration as this is convenient when you have to feed your starter frequently. Using only whole grain rye flour and water, I fed my starter every 12 hours (I’ve included details of the “feeding schedule” at the end of this post). This time interval is based on the growth cycle of yeast, where the yeast after an exponential growth phase reaches a plateau after 8-12 hours. This is the best time for feeding the starter.

There seems to be a consensus that a wet starter (i.e. 100% hydration) favors growth of lactic acid bacteria (LAB) which in turn produce acids. The low pH after 2 days in my starter suggests plenty of LAB activity, so the main challenge for me was to get the yeast growing. Considering the fact that the yeasts found in sourdoughs prefer areob conditions for growth, I should have whisked in more air with each addition of water. And I wonder if this is the origin of the widespread myth that you “catch wild yeasts from the air”. I’m quite sure whisking helps, but what you do is not to catch yeast, but rather feed oxygen to your starter. This needs testing though! Most starter recipes call for discarding of half or even more of the starter before each feeding. Even though it seems wasteful I wonder if an important effect of this is to dilute the acid produced by the LAB (the flour may also act as a buffer). This acid will to some extent slow the growth of yeasts (even though the sourdough yeasts are far more acid tolerant than the conventional brewer/baker’s yeast Saccharomyces cerevisia).

Bubbles indicating that the starter is active

Regarding temperature the growth optimum for LAB lies around 32-33 °C whereas the growth optimum for yeast is somewhat lower at 28 °C. The sourdough FAQ has further temperature recommendations which are illustarted in the graph below (data from sourdough FAQ). Holding this together with the notion (see for instance p. 272 in “The handbook of dough fermentations”) that lower temperatures (20-25 °C) favor acetic acid production (= stronger flavor) and higher temperature (> 32 °C) favors lactic acid production (= milder flavor) it immediately becomes clear why a starter kept at roomtemperature has little yeast activity and smells of acetic acid. It need not be ruined, but is desperately in need of dilution, aeration and higher temperature.

Effect of temperature on growth of lactic acid bacteria and yeast based on data for optimum growth and no growth from the sourdough FAQ

I’ve kept the starter alive since August and baked with it at least once a week. I make sure that I keep 50-100 g which I store in the fridge. I’ve also frozen a sample just in case. I’ve changed from 100% hydration to 67% hydration, as this simplifies the calculations a little. On the evening before baking day I feed the starter to a total starter weight of approximately 900 g. The next day I bake bread as follows (the exact numbers were calculated using an internet sour dough calculator with the following input: 3200 g total dough weight, 25% starter, 67% hydration of starter and final dough and 1.8% salt):

Sour dough bread
949 g water
1417 g flour *
800 g starter (67% hydration, 25% of total dough)
34 g salt

* for instance 300 g rye whole grain, 200 g rye fine, 300 g whole grain wheat and then plain all-purpose wheat flour up to 1417 g.

Mix water and flour mixed until all flour is wetted. Leave for 15-20 minutes (during which the autolyse proceeds – this eases subsequent mixing). Mix (see more comments below regarding method/machine for this) until dough is smooth, and while mixer is running add sour dough starter. Once the starter has been properly incorporated into the dough, add the salt. Cover and leave to rise until volume has increased 30-100% (I know – this is not very accurate…). I have left it in on my bench top, but while this worked well on warm August days, it seems to be less than ideal on colder October days. Leaving the dough to rise on top of the fridge might be a conventient compromise here as my current waterbath is not large enough to hold the mixing bowl with dough. The reason I use a starter with a 67% hydration is that I can be more sloppy when adding the starter to the sourdough as it will not change the hydration of the dough. After proofing and slashing I bake the breads on a baking stone which is preheated to 250 °C. Right beneath the baking stone I have a small oven proof dish that I fill with boiling water. This helps to moisten the air in the oven and it simulates the steam injection port of professional baking ovens. There are several reasons why this is important. Moist air is a better heat conductor than dry air, and it prevents the surface from drying out too early while baking, resulting in a better oven spring. Furthermore the moist air condenses on the cold surface of the dough which improves gelatinization of the starch. This in turn gives better crust formation. After 10 min at 250 °C I open the oven to let the moisture out, take out the dish with water, turn the heat down to 220 °C and close the oven door. I bake the breads to a core temperature of about 93-95 °C.

Here I bake two 800 g loaves on a baking stone. Notice the dish with water for steam generation.

I should comment on mixing. When kneading by hand I’ve had a tendency to add to much flour. In fact I think this is one of the reasons why I quit baking bread several years ago – I found that the breads I made generally were a little to dry with a poor crumb, and at that time I didn’t really sit down and think about these matters. In retrospect however there’s no doubt that baking bread and adding flour ad lib until the dough feels good to touch is NOT recommended. Well anayway not unless you stop adding flour while the dough is still quite sticky. The thing about doughs with a high percentage rye is that they are quite sticky, and they should be. This is the best argument you’ll ever get for buying a kitchen gadget: bread doughs are too sticky to be kneaded by hand! There you have it! I’ve settled with the Assistent from Sweden. It was formerly sold under the Electrolux brand, but is now marketed indepentendly, yet it is still produced at the very same factory as always. In the US the machine is known as the Magic Mill. It has a huge 7 L bowl that rotates. The roller is attached to a flexible arm, so if the dough is to hard to work the arm just moves to the middle of the bowl. This significantly reduces the chances of overheating the motor. There are of course other alternatives from Kitchen Aid, Hamilton Beach and Viking Range which seem robust, but I have no experience with these. However, I doubt that the average Kenwood can cope with more than 3 kg of bread dough (but please correct me if I’m wrong ).

Unlike most other machines, the bowl of the Magic Mill/Assitent rotates while the roller pushes the dough to the sides of the bowl

Sources for further reading

I’ve read quite a bit about sourdoughs, and what I’ve been looking for a simple correlation between temperature, hydration and fermentation time. An excellent source of information with lots of practical advice is the FAQ from rec.food.sourdough.

I think the best resource I’ve found sofar is Lorenz and Bruemmer’s chapter “Preferments and Sourdoughs for German Breads” and Teija-Tuula Valjakka, Heikki Kerojoki and Kati Katina’s chapter “Sourdough Bread in Finland and Eastern Europe” in “The handbook of dough fermentations”. I will have to study these more carefuly.

There are quite a number of academic publications which also touch upon the effect of temperature on acid development. Here are some snippets:

“Controlled production of acetic acid in wheat sour doughs”:

…temperature has no significant effect, and that fructose is more efficient in influencing the FQ than dough yield.

FQ = fermentation quotient = lactic acid / acetic acid

“Volatile compound and organic acid productions by mixed wheat sour dough starters: Influence of fermentation parameters and dynamics during baking”:

… Low temperature (25 degrees C) and sour dough firmness (dough yield 135) were appropriate for LAB souring activities but limited yeast metabolism. Raising the temperature to 30 degrees C and semi-fluid sour doughs gave more complete volatile profiles …

“Sourdough: a tool for the improved flavour, texture and shelf-life of wheat bread” (Ph.D. thesis of Kati Katina):

The production of acids depends also on other things such as fermentation temperature, time and dough yield. Optimum temperatures for the growth of lactobacilli are 30-40 °C depending on strain (Stanier et al. 1987) and for yeasts 25-27 °C. In general, a higher temperature, a higher water content of sourdough and the utilisation of wholemeal flour enhances the production of acids in wheat sourdoughs (Brummer and Lorenz 1991, Lorenz and Brummer 2003).

I must admit that I’m a little confused as some of these snippets seem to contradict. It might be that I’m overlooking something important though and that I’m taking results out of their context. Any insight from my readers on this will be greatly appreciated!

Starter details
Here’s the details from my notebook on how I fed my sourdough starter. As I mentioned above, I wonder if discarding dough in the process actually does make sense after all.

• July 29, evening: 50 g rye + 50 g water
• July 30, morning: 25 g rye + 25 g water, evening: small bubbles (!), 50 g rye + 50 g water
• July 31, morning: 50 g rye + 50 g water, evening: pH measured to 3-4 with strips, fed with 50 g rye + 50 g water
• August 1: morning: 50 g rye + 50 g water, tested for bread baking, result: not active enough, feeding continued evening: 50 g rye + 50 g water
• August 2: morning: 50 g rye + 50 g water, evening 50 g rye + 50 g water
• August 3: morning: 50 g rye + 50 g water, evening: no bubbles, discarded all except ~100 g, fed with 50 g rye + 50 g water
• August 4: morning: 50 g rye + 50 g water, evening 50 g rye + 50 g water
• August 5: morning: 50 g rye + 50 g water, evening: big bubbles, the starter is active, CO2 production evidenced by tickling in nose, fed with 60 g rye + 60 g water and 2 x 100 g samples taken for fridge and freezer as fallback points
• August 6: morning: 50 g rye + 50 g water, first successfull bread made with the starter

I show my raw data to illustrate that it’s not straightforward, even with temperature control.

A fool proof starter – is it possible?
What I’m hoping to achieve can be summarized as follows: A “fool proof”, robust and quick method to obtain a sourdough starter that’s as simple as possible, using only flour and water (possibly with addition of some fruit) without having to waste anything of the starter. Temperature is maintained using a thermostated water bath. Preferably it should be possible to adjust the fermentation quotient (ratio of lactic acid/acetic acid) and the total titrable acid content by means of temperature, time and hydration/dough yield.

Last year’s book bonanza (Remember The Big Fat Duck Cookbook, Alinea and Under pressure right? Not to mention BakeWise, The Flavor Bible (not science, but I love their systematic approach), Cooking – The Quintessential Art, A day at el Bulli, the bilingual Sous-Vide, the German Verwegen Kochen and the Danish Molekylær gastronomi – did I miss any?) will be difficult to beat, but several interesting books will appear this fall as well. It’s as if this field is exploding with books now. When I first set up the webpages which later evolved into Khymos only a handful of books were available (you can travel back in time and view the single page from 2003 – only in Norwegian, sorry), but even I have a hard time now keeping track with all the books which cover the interesting intersection between cooking and science, aka molecular gastronomy. Sometimes I think – is this book really necessary? Do we need it? What does it add? But addicted as I am, I can’t help it – so I’ll probably get hold of most of these books as they become available

Hervé This is a pionéer of molecular gastronomy and has an impressive publication list in French. Fortunately more and more of his books are now becomming available in English as well. In recent years we have seen Building a meal, Cooking – The Quintessential Art, Kitchen mysteries – Revealing the science of food and Molecular gastronomy: Exploring the science of flavor. His latest book The Science of the Oven is scheduled to appear in September/October. According to the publisher Hervé This unravels “the science behind common culinary technique and practice” and “translates the complex processes of the oven into everyday knowledge for professional chefs and casual cooks; demystifies the meaning of taste and the making of flavor; describes the properties of liquids, salts, sugars, oils, and fats; and defines the principles of culinary practice, which endow food with sensual as well as nutritional value”. As usual I haven’t been able to identify the original title in French, maybe someone can help?

For the first time ever, every single dish served at elBulli has been collected in a single book. The book Food for tought: Thought for food explores the creativity of Ferran Adria and his team and features a ” lively dialogue between the most potent critics and creators of the art and gastronomic worlds, including Heston Blumenthal, Bill Burford, Jerry Saltz, Massmiliano Gioni, Anya Gallaccio, Peter Kubelka, Antoni Miralda, Carsten Holler, Bice Curiger, Adrian Searle, Davide Paolini”. -Professionally, I can die after this book, says Ferran Adria. In case you wondered about the cover drawing – yes it’s Ferran Adria drawn by Simpson creator Matt Groening. (If you’re not famous enough to have him portray you check out the website simpsonizeme in stead.)

The no-knead bread has been a craze on the internet since the 2006 article in NY Times. From a chemical perspective two things are particularily interesting about this bread. First, by using a wetter dough the mobility of glutenin and gliadin increases, allowing sufficient gluten to form without kneading. Second, by baking the bread in a preheated pot with a closed lid one emulates the effect of a professional steam oven – the higher humidity gives a more efficient heat transfer, better crust formation and ensures a proper oven spring. There are several other books which ride the wave of “no-knead artisan breads”, but it’s probably worth lending an ear to Jim Lahey who (to the best of my knowledge) pioneered this. His book My Bread: The Revolutionary No-Work, No-Knead Method is scheduled for release in October.

When reading up on sourdougs I was a little disappointed by The bread bible (but what more is to expect when one of the best books I’ve found on the subject is the much more technical-not-for-the-general-audience Handbook of dough fermentations by CRC?). However, the books by Peter Reinhart have been more rewarding. I own Crust and crumb and I’ve learnt a couple of things from that book. As the title of his latest books suggests, Artisan breads every day, Reinhart incorporates the latest no-knead, no-fuzz trend in this book. The publisher promises that the book will teach you how to bake the “highest quality loaves”, and I’m quite sure you will if you follow the recipes carefully. But that you’ll be able to do so “in a fast and convenient fashion” is perhaps a little too optimistic. When did artisan breads become fast and convenient?

As the title of Modern Gastronomy: A to Z by Ferran Adria suggests, the book has a lexical format and covers the terminology used to describe “the nature of ingredients and why these ingredients produce certain reactions”. It’s written in plain language and even claims to teach the readers “everything they need to know about the science of cooking”. I seriously doubt that claim, but the book is probably quite useful anyway as a starting point and a handy reference guide. And one more thing – it’s published by CRC, a publisher that normally addresses a professional audience. Too me it suggests that the book is quite different from The Science of Good Food: The Ultimate Reference on How Cooking Works (which is OK, but not superb).

And finally, for those who didn’t fork out a fortune to buy Heston Blumenthal’s monumental The Big Fat Duck Cookbook last year, now is your chance to buy a cheaper version of the same book! Seriously – if you’re only buying one book this year, get this one. You get the complete content of the book that was published last year, minus the luxurious box, silver edged pages, colored ribbons and a couple of pounds! The book is in fact three books in one – you get an autobiography of Heston and the history of The Fat Duck, you get 50 signature recipes and in the third section a number of essays on the science behind it all.

I think I’ve covered the most relevant “sciency” foodbooks appearing this fall, but feel free to fill me inn if there are books I have overlooked.

The Canadian sommerlier François Chartier (he has an extensive website featuring several blogs, including a section named Sommellerie moléculaire) is out with a new book on food and wine pairing. It’s not just another (superfluous) book on the subject. As the title Papilles et molécules (= Tastebuds and Molecules, unfortunately not available in English) suggests there is some science involved. It turns out in fact that he has applied the principles of flavor pairing to food and wine. With help from Richard Béliveau from Agriculture and Agri-Food Canada and Martin Loignon from PerkinElmer he has analyzed wines and food and comes up with the following suggestions for lamb, as described in the article “Chemistry-set wine pairing”:

Having roast lamb? Don’t waste it on an ill-advised red Bordeaux, the old standby trotted out by generations of sommeliers. Lamb’s characteristic flavour comes from thymol, an aromatic compound found in the oil of, yes, thyme. It’s also a flavour note associated with red wines from the southern Languedoc region of France, such as Minervois, Corbières or St. Chinian.

Other combinations mentioned in the article include:

rosemary – white wines from northern Alsace
pork – oaked red wines
curries – viognier
cinnamon – pinot noir, grenache, ice cider, oloroso sherry

François Chartier also introduces “bridge ingredients”. Mint, which goes well with sauvignon blanc, shares aroma compounds with parsley, fennel and tarragon. Based on this he theorizes that sauvignon blanc should also pair well with dishes based on these ingredients.

As far as I can see (with my very limited high school French) there are no links or references to all the other activities in the field: Heston Blumenthal’s pioneering of the concept together with François Benzi from Firmenich, the Food pairing website – not even to the TGRWT food blogging event Nevertheless it’s nice to see that the concept has now been applied to food and wine as well. As I don’t own the book yet I can’t tell whether François Chartier includes odor activity values in his discussion or not (but I certainly hope he does!).