Since The fat duck and El Bulli were announced “Best restaurant” in 2005 and 2006 respectively by Restaurant Magazine, molecular gastronomy has received increased attention. This has also resulted in a greater demand for the ingredients used, especially various thickeners, stabilizers and emulsifiers. In Europe, these have been given E-numbers ranging from E400-E499. The other ranges include colours (E100-199), preservatives (E200-E299), acidity regulators, anti-oxidants and anti cacking agents (E300-E399, E500-E599) and flavour enhancers (E600-E699). The European numbering is a sub-set of an international list of food additives, the Codex Alimentarius.

The Alchemist’s pantry - an early predecessor to that of the modern cook! (picture source)

Some of the most used ingredients in restaurant kitchens are listed below:

E322 Lecithin
E327 Calcium lactate
E331 Sodium citrates
E400 Alginic acid
E401 Sodium alginate
E402 Potassium alginate
E403 Ammonium alginate
E404 Calcium alginate
E406 Agar
E407 Carrageenan
E407a Processed eucheuma seaweed
E410 Locust bean gum (Carob gum)
E412 Guar gum
E413 Tragacanth
E414 Acacia gum
E415 Xanthan gum
E416 Karaya gum
E417 Tara gum
E418 Gellan gum
E422 Glycerol
E425 Konjac
E440 Pectins
E441 Gelatine
E461 Methyl cellulose
E463 Hydroxypropyl cellulose
E464 Hydroxy propyl methyl cellulose
E466 Carboxymethyl cellulose
E473 Sucrose esters of fatty acids
E474 Sucroglycerides
E621 Monosodium glutamate
E631 Disodium inosinate
E636 Maltol
E953 Isomalt
E1103 Invertase
E1400 Dextrin
Transglutaminase (no E-number as far as I know)

(click here for the full list)

Unfortunately these ingredients are not available in normal stores (with one exception: gelatine). Of course they are readily available in large quantities to the food industry, but lately suppliers of sub-kilogram amounts have appeared. I have collected a list of these suppliers - if you’re not on the list, drop me a note at webmaster((a))khymos((dot))org). Recent additions to the list include Kalys, texturePro and DCDuby.

One challenge with the different shops is that some products come with little or no technical specification. For cellulose ethers for instance, Dow provides an extensive range to industrial customers (more on this in a previous blog post on cellulose ethers), just to give you an idea of the product range available.

I should also add a closing remark om tools: some companies sell syringes, measuring spoons etc in “nice boxes”. However, these tools can most often be obtained for a fraction of the price at any drug store, pharmacy or kitchen hardware store.

Once you have stocked up with your cooking chemicals, the next question is - how do you use them? I would recommend the information provided by INICON on molecular gastronomy and textures (MANY pdf’s to download). Also, many of the suppliers have recipes on their homepages.

Videos from the MG seminar in Belgium held on November 20th last year have generously been made available for free on the net. There are four videos to watch: presentations by Prof. Peter Barham (‘Molecular Gastronomy? The science of taste and flavour’) and Prof. Jorge Ruiz (‘Methods in the kitchen: the science behind’) plus demonstrations by Kobe Desramault and Sang Hoon Degeimbre.

Also, Bernard Lahousse (who is in charge of food for design and a co-organizer of the MG smeinar) has let me know that the next seminar will be held on March 16th with the title “A world of Pinot noir” - focus is on wine, but with live MG demos. Stay tuned!

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):

My fellow blogger on molecular gastronomy, Göde Schüler (check out his German MG blog Gourmetrics) found a great video on YouTube. The video shows how a red beet paste mixed with alginate solidifies when dripped into a solution of calcium lactate (this solution is normally clear, the yellow colour comes from extensive use).

Chef Simon (French, click here for babelfish translation) has a nice page on alginates as well. Another french page here (with english translation by babelfish). You can find links to more technical information (free pdf’s) on alginates in the static pages of khymos.org.

The chemical principles put simply are as follows:
Sodium alginate is water soluble and can be mixed with many different fruit/vegetable juices and purés. When dripped into a solution containing calcium ions, each calcium ion (which holds a charge of +2) knocks away two sodium ions (each holding a charge of +1). The alginate molecule contains loads of hydroxyl groups (OH’s) that can be coordinated to cations (that’s ions with a positive charge such as sodium and calcium).

When alginate is coordinated to sodium, it’s a very flexible chain. When sodium is replaced by calcium however, each calcium ion (black dots in the image below) coordinates to two alginate chains, linking them together. The flexible chains become less flexible and form a huge network - a gel. The fun thing is that this happens within seconds after the alginate mixture is dripped into the water bath with the calcium ions.

Approximate concentrations:

• Fruit/vegetalbe juice/puré with 1-2% sodium alginte
• 2% calcium chloride solution (approx. 10g in 1/2 L of water) - because calcium chloride has a slightly bitter taste, it is a good idea to rince these pearls with water before consumption. This is also the reason why calcium lactate is often used in stead (as shown in the video).

Update: The Frog Blog has nice posts with pictures showing how Jay Veregge and Joel Robuchon utilize alginate gels. Also, check out this “caviar” maker for dripping 96 drops of sodium alginate solutions into calcium chloride at once.

Every now and then I end up explaning to friends how they can make good pizza at home. One of the main issues is how to obtain the nice, crisp crust. And of course I’m referring to Italian pizza now, not American pan pizza. The simple answer to this is: use a baking stone (pizza stone) (assuming of course that the dough and filling is home made). Or if you like going to extremes: get a wood fired baking oven made from stone. But with a simple baking stone, you can achieve prette good results even with an electric/gas stove. There is a simple explanation: When a pizza dough is baked on a metal plate, the evaporating moisture is not able to escape from underneath the pizza. The result is a soggy, unappetizing crust. Also, the cold dough will let the temperature of the metal plate/sheet drop relatively quickly. As a result, the yeast dough will not rise as much before the gluten network solidifies and prevents further rising of the dough.

A baking stone is made from a porous ceramic material. It’s heat capacity is good (much higher than that of a metal plate/sheet) and as a result, when the cold dough is placed on the baking stone, it still has enough heat to make the pizza rise immediately. Secondly, the fact that the baking stone is porous lets it absorb moisture from the pizza. This is what gives the nice crisp crust as it transports moisture away from the pizza.

I also recommend to set your oven at the highest temperature possible - preferebaly in the range 250-300 °C (480-570 F). At this temperature, the pizza will be ready in less than 10 minutes. And remember - don’t use soap when cleaning your baking stone. Remember that it’s porous and you definitely don’t want your next pizza to taste like soap. Just scrape of residues of cheese once they have turned to carbon dust. If necessary, you can wipe it of with a moist paper towel.