Khymos » hydrocolloids

“Texture” to be updated with pictures

Martin Lersch — Sun, 03 Jan 2010 00:03:24 +0000

Do you think “Texture” would benefit from some pictures? Now you are invited to contribute with your very own pictures to illustrate the recipes! (A big thank you to Chad Galliano who let me use his picture of foamed garlic oil!)

A picture is worth a thousand words, and this is also true for recipes. Several of you who have downloaded “Texture – A hydrocolloid recipe collection” have asked for pictures and now it’s time to do something about that! A picture can illustrate texture well and is an excellent supplement to the descriptions. I therefore invite to you to contribute to the recipe collection by taking pictures to accompany the recipes. But before you run to grab your camera, please take a note of the following:

Pictures should clearly show the component described in the recipe. If you take a close up picture against a neutral background it’s good if one still has a feeling of what the scale is.
Only send a picture if you actually followed the recipe! This way the picture can also serve as an indication that the recipe as been tested. However, if you for some reason have modified a recipe for a better or different result I would also be very interested in hearing about this.
Pictures should be in focus and well lit. But remember that Photoshop can do wonders, so please do send pictures even though the colors seem a little dull.
Pictures will be cropped to a 1:1 aspect ratio as shown above
Preferred minimum resolution is 450 x 450 pixels
It’s a requirement that the picture is taken by you and that you are willing to provide it for use in “Texture – A hydrocolloid recipe collection” under a Creative Commons Attribution – Noncommercial-Share Alike 3.0 Unported License since the whole recipe collection is published under such a license
I reserve the right to crop pictures and do color/brightness/sharpness adjustments
I reserve the right not to use pictures received (and I only intend to include one picture for every recipe)
Pictures will be attributed to the photographer as shown in the above illustration.

If you have read the above and agree you’re ready to send your texture pictures to me at this email address: texture.pictures (at) gmail.com. Remember to include the name of the recipe photographed and your name as it should appear under the picture. Thank you very much for helping me make this collection even more useful

Help needed with densities of hydrocolloids

Martin Lersch — Wed, 30 Apr 2008 21:25:25 +0000

Photo by Mel B via flickr.com (CC).

Measuring powders by volume has serious limitations (more on this later in an up-coming post), but one great advantage is that for small quantities going by volume can sometimes be more accurate than weighing them. At least when you work in a kitchen and don’t have access to professional lab scales. When a scale shows 0.1 g, the true weight could be anywere from 0.05-0.149 g due to rounding (that’s ± 50%!). Not to mention the fact that cheap balances aren’t always very accurate for such small amounts, even though they feature a 0.1 g resolution.

I’m currently working on a major revision of the collection of hydrocolloid recipes. One thing I would like to include is a table with densities of the hydrocolloids and chemicals used. When the densities are known, it’s possible to give some rough advice for what volume to use (this on-line conversion calculator has the densities of many common ingredients). This could ease small scale preparations. It will also make it easier to calculate the percentage of hydrocolloid used in recipes where the amount is given by volume. I’ve measured the hydrocolloids I have at hand, but I need your help to fill out the table and repeat the measurements I’ve done. With enough measurements I could also do some statistics and make a plot. I’m also interested to see if there is much variation between different brands.

How to determine the density:

Find a suitable measuring spoon, cup, shot glass, container – whatever you have – with a volume of at least 10 mL (I used one of about 30 mL).
Put the empty container on the balance and use the tara function.
Fill completely with water and weigh again. The difference gives you the exact volume (for water 1 g = 1 mL).
Dry the container, put it on the balance and use the tara function.
Spoon the hydrocolloid into the container, tap the side gently once or twice with the spoon and level off.
Weigh the container again and write down the mass of the hydrocolloid.
To calculate the density of the hydrocolloid, divide the mass by the volume you obtained for your container. This gives you the density of the hydrocolloid with units g/mL.

Repeat steps 4-7 for each hydrocolloid you have at hand. I would very much appreciate if you email your results directly to me at webmaster (@) khymos (.) org. Please include the volume you measured (larger volume means more accurate measurement) and which brand you used. It will be interesting to see if the brands differ a lot.

I should add one coment about the products from texturePro: this picture indicates that all (?!!) the texturePro hydrocolloids are mixed with maltodextrin (please correct me if I’m wrong – it could be that this only applies to the cocktailPro kit). And I think the same is the case for several of the Sosa products. This increases the volume and eases the use of a measuring spoon (which comes with every texturePro kit), but unless the exact proportion of hydrocolloid to maltodextrin is known, following other recipes than the onces included with the kit is more or less impossible. Let me know if you have further details on the hydrocolloid/maltodextrin ratio in texturePro or Sosa products.

In advance: Thank you very much for your help!

First experiments with sodium alginate

Martin Lersch — Fri, 30 Mar 2007 20:54:30 +0000

Here’s some pictures and a video of my first experiments with sodium alginate and spherification. I used sodium alginate from the Texturas series and calcium chloride from a drug store. Needless to say, I’m very fascinated by the texture and the whole process. I have blogged about the chemistry behind previously.

Materials used:
2.0 g sodium alginate
200 g water (with low calcium content!)
50 g blueberry syrup

2.5 g calcium chloride
500 g water

Procedure:
2 g sodium alginate and 200 g water were mixed vigourously in blender. The mixture was then left to stand for some hours to get rid of the air bubbles. 50 g blueberry syrup was then added to the sodium alginate solution. A calcium chloride bath was prepared by dissolving 2.5 g calcium chloride in 500 g water. The sodium alginate/blueberry mixture was dripped into the calcium chloride bath using a plastic syringe with a steel cannula. After 1-3 min the pearls were removed and rinsed with water.

More detailed procedure with pictures and video:
I had to obtain a scale with a 0.1 g accuracy to weigh out 2.0 g of sodium alginate (my first experiments using a normal kitchen scale failed). The model I got cost about $100 and is inteded for school laboratories. Amazon provides several scales with this accuracy.

I used a blender to dissolve sodium alginate in water. This incorporates a lot of air in the mixture which we don’t want. It could possibly be avoided by using an immersion blender/mixer. However, I just left the alginate solution on the bench and after 3-4 hours the air bubbles had all escaped from the solution.

Plastic syringes and cannulas can be obtained from your local drug store or pharmacist. I found it was easier to produce evenly sized drops with a sharp cannula (CAREFULL!) than with just the plastic tip of the syringe. This of course depends on the viscosity of the solution. By thickening (with xanthan for instance) you can produce larger drops.

After 1-3 min the spheres were removed from the calcium chloride solution and rinsed with clean water. I dried the spheres carefully using a kitchen towel or paper.

Definitely looks like caviar when presented on a spoon like this!

Larger spheres were made by filling a small measuring spoon with the alginate mixture (I used a syringe for this so the outsides of the spoon would not be covered with alginate solution) and carefully emptied it into the calcium chloride bath. It takes some trial and error to achieve good results.

The spheres are suprisingly robust and can be handled without rupturing.

If cut with a knife, the spheres rupture and the liquid contents flows out.

The small spheres didn’t taste much, so I could have added more blueberry syrup. The large spheres however had a nice taste. The surprise element when they rupture in your mouth is very nice!

Practical molecular gastronomy, part 4

Martin Lersch — Sat, 17 Mar 2007 22:00:14 +0000

(Photo by vintage_patrisha at flickr.com)

4. Learn how to control the texture of food

Taste and flavour normally get more attention when food is discussed, but the texture of food is equally important and our tongue is very sensitive, not only to taste and temperature, but also to the texture of food. The texture of food determines it’s mouthfeel and it is related to many physical properties of the food. Wikipedia lists the following aspects of mouthfeel (click to see the full description of each aspect) which can be useful when analyzing food:

Adhesiveness, Bounce/Springiness, Chewiness, Coarseness, Cohesiveness, Denseness, Dryness, Fracturability, Graininess, Gumminess, Hardness, Heaviness, Moisture absorption, Moisture release, Mouthcoating, Roughness, Slipperiness, Smoothness, Uniformity, Uniformity of chew, Uniformity of bite, Viscosity, Wetness

I will barely scratch the surface of how texture can be controlled by highlighting a couple of topics and point you to further resources. Hopefully it will spark your interest and give some new ideas for you to play with in the kitchen. Those interested in a comprehensive review of food texture are referred to the CRC handbooks on food texture (volume 1: semi-solid foods, volume 2: solid foods).

What determines the texture of food?
Put very simple, it’s the relative amounts of air, liquid and solids that determines the texture of food. This is complicated by the fact that liquids have different viscosities. Furthermore the air, liquid and solid ratio is not necessarily constant. A liquid can solidify or evaporate, solids can melt or dissolve, and air bubbles can escape during cooking or storage. An elegant but quite abstract way of describing the complicated mixtures of air, liquids and solids found in food, is to use the CDS formalism (CDS = complex disperse systems), introduced by Hervé This.

(Photo by Subspace at flickr.com)

How can texture be controlled and changed?
Texture can be controlled by temperature, pH, air/liquid/solid ratio, osmosis, hydrocolloids and emulsifiers – to mention a few. Here’s some examples:

Heating induces a change in the structure of proteins referred to as coagulation or denaturation. Typical examples are the boiling of eggs and the cooking of meat. When proteins denature they contract and become firmer. There are several helpful tables relating the doneness of different meats to temperature.

At around 70 °C (160 °F) collagen, the connective tissue in meat, turns into gelatin. As a result the meat becomes more tender, which is desireable in stews and other slow cooked meats.

Heat causes air/gas to expand and water to evaporate to give a foamy/airy texture. For example, experiments have shown that it is mainly the evaporation of water that causes a soufflé to rise.

Heat will cause certain hydrocolloids to solidify (for exaple methyl cellulose) whereas it will cause others to melt (such as gelatin).

Brining meat can greatly improve it’s texture and juicyness. This is done by immersing the meat in a 3-6% salt solution from anyhere between a few hours to two days before cooking.

Frozen water in the form of tiny ice crystals are important for the smooth texture of sorbets and ice cream. Ice cream that has been partly melted and frozen again will grow larger ice crystals that impart a coarser texture to the ice cream.

Acidic solutions (low pH) can cause proteins to denature. This allows fish to be cooked without the use of any heat. An example is the use of lime juice in ceviche.

Emulsifiers, thickeners and gelling agents have almost become synonymous with molecular gastronomy for many. They can greatly alter the texture of foods and typically only a very small amount is required. Where gelatin was the only gelling agent videly available to cooks in Europe and America only a decade ago, this has changed with the advent of many internet suppliers of speciality ingredients.

Cooking under vacuum can create new and exciting textures. First of all it’s a way of removing excess water without having to raise the temperature all the way up to 100 °C. When the water is removed, this will create pockets of air in the food, and when the pressure is released, the liquid surrounding the food that is prepared will rush in and fill these pockets. There is a commercially available vacuum cooker, but a DIY version can be made from a pressure cooker and a vacuum pump.

(Photo by Trinity at flickr.com)

Green leaf vegetables such as lettuce loose water upon storage. As the pressure inside the cells drops, the leaf becomes softer. By immersing the leaves in cold water for 15-30 min, thanks to osmosis, water will enter into the cells again. As the pressure increases, the leaves become crisper.

Air bubbles can greatly modify textures, and foams really are ubiquitious (which becomes obvious if you read the book “Universal foam – from cappuccino to the cosmos”). Ferran Adria’s espumas have become very popular, as has his recent invention, the Espesso. Air bubbles are also very important for the texture of ice cream, in fact ice cream is nearly 50% air (just consider the fact that ice cream is sold by volume, not by weight!).

A very recent addition to the modern kitchen pantry is the enzyme transglutaminase. The enzyme acts like a meat glue and Chadzilla has nice blog post on his transglutaminase experiments.

There are also enzymatic counterparts of transglutaminase available: proteolytic enzymes also known as proteases. You can find them in pineapple (bromelain/bromelin), papaya (papain), figs (ficin) and kiwi (actinidin) – and they are capable of degrading proteins and muscle tissue. Despite this, they have only found limited use in marinades, as their action can be difficult to control (as Nicholas Kurti experienced, look for the “But the crackling is superb” link).

When mixing flour and water, glutenin and gliadin react to form gluten which gives bread it’s elasticity and plasticity. Addition of 1-2% salt to bread tightens the gluten network and increases the volume of the finished loaf. Similarly, addition of 1% oil to the dough (after the first kneading) can further increase the volume. Larger amounts of fat added before kneading will interfere with the formation of long gluten strands, hence the name shortening.

The no-knead bread that recently hoovered around in the blogosphere challenges the conventional wisdom that bread needs kneading to get a good texture.

Once bread is baked, the staling process starts. Staling does not necessarily involve loss of water from the bread and is caused by crystallisation (or retrogradation) of starch. In this process water molecules are trapped. The process proceeds fastest at 14 °C, but is halted below -5 °C. This is the reason why bread should be stored at room temperature. The staling process can be slowed down by addition of an emulsifier such as lecithin which is abundant in egg yolk.

A way of turning high fat foods and oils into powders is by the use of tapioca maltodextrin. Hungry in Hogtown has shown how Nutella can be turned into a powder.

Check out my previous blogpost for an overview of the tips for practical molecular gastronomy. The collection of books (favorite, molecular gastronomy, aroma/taste, reference/technique, food chemistry) and links (webresources, people/chefs/blogs, institutions, articles, audio/video) at khymos.org might also be of interest.

Chow: Behind the scenes at Alinea

Martin Lersch — Mon, 26 Feb 2007 21:34:13 +0000

The red sheet (in the not yet finished dish) is made by heating Campari, beet root juice, salt and sugar, followed by addition of agar agar. The color and texture look marvelous!

Chow has a nice picture-by-picture guide (featuring photos by Stephanie Willis) to the dish “Short rib – beets, cranberry, Campari” served at Alinea.

…If only it were that simple. Chef Grant Achatz says the actual ingredients are “short rib, beet-Campari juice, roasted baby golden beet, beet-green marmalade, braised beet greens, beet pâte de fruit, beet chips, three different types of fennel garnish, cranberry sauce, caramelized fennel purée … man, I guess that is a lot.” A colleague reminds him about fennel pollen, cranberry powder, and Murray River salt.

Ingredients for molecular gastronomy

Martin Lersch — Sun, 14 Jan 2007 00:15:02 +0000

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.