Archive for the ‘hydrocolloids’ Category

TGRWT #15: Smoked salmon in cocoa gel with lime

Sunday, March 1st, 2009

The TGRWT #15 challenge was to pair smoked salmon with dark chocolate. I decided to encase a piece of hot-smoked salmon in a cocoa gel and serve it with sugared slices of lime. But as you can see from the pictures quite a lot went wrong… But it tasted quite nice!

TGRWT #15: Dark chocolate and smoked salmon

Wednesday, February 4th, 2009


This month’s round of “They go really well together” (TGRWT #15) is hosted by Mexmix and foods to pair this time are dark chocolate and smoked salmon. As usual you can find instructions on how to participate in the announcement post. Don’t forget to check out Rob’s summary of the malt and soy sauce round.

TGRWT #14: Beer sorbet with soy marinated melon

Saturday, January 31st, 2009


tgrwt-14As malt was one of the foods to pair for this month’s TGRWT I decided to do something with beer. I first considered making a beer gel since the Alinea book has a nice recipe (with potassium citrate and kappa carrageenan – I included the recipe in the hydrocolloid recipe collection), but since I didn’t have carrageenan at hand I decided to try a sorbet. A quick search gave me 4 recipes (links in the table below) and in order to compare these I decided to calculate sugar/beer and sugar/liquid ratios as these are quite crucial in order to obtain the desired consistency of a sorbet. The results are shown in the table below. (more…)

Hydrocolloid recipe collection v.2.2

Friday, December 19th, 2008

An updated version of “Texture – A hydrocolloid recipe collection” is now available for download (version 2.2). There are two file sizes available: screen resolution (~1 MB) and high resolution for printing (~5 MB). Some recipes have been added bringing the total number up to about 270 recipes. Apart from this the version includes corrections of typos and updates of indexes and the supplier list. There is a new index for alcoholic preparations plus a small glossary. Again I should mention that I’m very grateful for feedback from readers and users of this recipe collection. Thank you very much with helping me improve the document! If you find typos, wish to comment on something or have suggestions on how to improve the collection, please do not hesitate to write me an email at webmaster (at) khymos (.) org or just write a comment in the field below.

Cherry jams with a twist

Sunday, August 3rd, 2008

We have a small garden with a single tree. It’s a sweet cherry tree and this year must have been one of the best ever. In May it was overthrown with flowers. Last year I made some jam which came out OK, but the drawback with sweet cherries is that their taste doesn’t really compare with that of sour cherries. They’re good to eat, but not as good for cooking and jam as their sour cousins. The summer last year was quite wet and cold which could explain the fad taste, but this year however has been quite hot and the cherries grew darker and sweeter as summer proceeded.

I decided to give cherry jam another try. To improve the flavor even further, I was pondering on adding spices. My mom has previously added cloves and cinnamon to plums when making jam. The first place I looked was under cherries in the book “Culinary artistry”. Among the numerous suggestions for flavor pairings it was black pepper and lemon that caught my attention. Who would have thought? I made a small test batch and was quite pleased by the “bite” provided by pepper so I proceeded with a full batch. I used a pre-mixed gelling sugar from Danisco sugar (which contained sugar, pectin, a preservative and an acid), but you could use whatever pectin you have at hand. Just follow the instructions on the pack (more on the science further down).

Having added pepper and a little of the sugar to get an idea of how it would turn out, it almost felt as if ginger was already there so I added a little more to accentuate that. The other spices were added to round everything off. The pepper taste is quite noticeable if you eat the jam by itself, but on buttered bread or toast it’s really nice. I also suggest that you try it with different semi-soft and hard cheeses such as Emmentaler, Jarlsberg, Prästost, Parmesan or Pecorino. My wife thinks it’s a little to much pepper, but for me it’s just perfect. In German this jam would be known as a Herrenmarmelade (a gentleman’s jam). If you’re not very fond of pepper however it’s a good idea to start with half the amount of pepper.

Spicy cherry jam with pepper
3.7 kg depitted sweet cherries
7.0 g black pepper, ground
0.8 g cloves, ground
0.7 g ginger, ground
1.3 g anis seeds, ground
0.8 g star anis, ground
zest and juice from 1/2 lemon
2.2 kg gelling sugar (with pectin and preservative)

Place enough jars in a cold oven and heat to 120-130 °C to sterilize them (this is more convenient than in boiling water). Depit cherries (conveniently done with a cherry stoner) and cut in four (helps you discover those stones that eluded the cherry stoner). Add spices and bring to boil. Remove any remaining pits that float up to the surface. Pureé with immersion blender (hopefully you will not hear the sound of cherry pits being crushed at this stage). Add gelling sugar. Let boil and skim of foam. Fill the hot jars immediately. And remember – as all chemists know – hot glass looks just like cold glass! Use a canning funnel to avoid spilling jam on the sealing surface of the jars. Leave to cool for 10-15 minutes and then screw on lids. I usually wipe the inside of the lids with 40-60% alcohol and then screw them on tightly before the alcohol has evaporated. There’s more at the end regarding the procedure for closing the jars.

This way of canning is very convenient and the jam will keep for several years in closed jars if kept in a cool, dark and dry place. This is due to the high sugar concentration (sugar binds water, and unless water is available, molds won’t grow), the low pH and – if added – the presence of preservatives. A more tedious way is to sterilize the jars after filling by boiling in water. This is no doubt the best way to sterilize the jars, but for jams with a high sugar content and a low pH it’s a little overkill. The National Center for Home Food Preservation in the US has more information about this (but notice that there are different traditions – I wonder if there is a divide between Europe and North America?). There are also many books about this and good place to start would be the “Ball Blue Book of Preserving”, better known as BBB among home canners. If you chose this method you should probably use a little more pectin as the additional heating at low pH will degrade some of the pectin making the jam more runny.

Using black pepper in a jam worked really well so I googled this and found Clotilde’s recipe for a strawberry jam with pepper and peppermint. She got it from Christine Ferber, author of “Mes confitures: The Jams and Jellies of Christine Ferber” which has recipes organized according to season. As mint was also mentioned as a good flavor pairing for cherries in “Culinary artistry” I thought I’d give pepper and peppermint a try.

Cherry jam with pepper and peppermint
2.2 kg depitted sweet cherries
1.3 kg sugar
2.4 g fresh peppermint leaves
2.8 g black pepper, ground
zest and juice of 1/2 lemon
1 pack of Certo fruit pectin*

Depit cherries and cut in four. Add pepper and peppermint and bring to boil. Remove any remaining pits that float up to the surface. Pureé with immersion blender. Add pectin and stir until dissolved. Add sugar. Let boil and skim off foam. Sterilize and fill jars as in the previous recipe.

[ * The Certo pack weighs 70 g and contains sugar (for easier dispersion of the pectin), citrus pectin, citric acid to get the right pH for gelling and a preservative (ascorbic acid). ]

This jam was dominated by peppermint and the pepper could barely be noticed. I found it very refreshing and there is a surprise element as the red color does not suggest the presence of peppermint. Apart from the obvious use as a bread spread, I can imagine that this jam would be very nice with roasted meat, especially lamb, reindeer, elk and perhaps also wild game.

Having experimented with different spices and peppermint, my wife asked me to also make a batch of plain cherry jam which I happily did. But next year I would like to try making cherry jam with red wine!

As you can imagine, I couldn’t do all this without offering the chemistry behind some thoughts. Pectin chemistry is quite complicated though and there are several types available (low methoxyl, high methoxyl and amidated – so far I’ve only included the two first in “Texture – A hydrocolloid recipe collection”). Commercial packs of pectin for home use do normally not specify which type of pectin they contain, but I assume that it is the high methoxyl which gels in the presence of sugar and at low pH (as opposed to the low methoxyl which requires calcium ions to gel). The easiest is probably to follow the instructions that come with the pack you chose. Always add pectin before you add sugar (unless you premix them). The reason for this is that the gelling of high methoxyl pectins is promoted by sugar. If you add sugar before pectin, it will be very diffult to get the pectin properly dispersed and dissolved (it can be done with an immersion blender though – I’ve tried that once). Ready to use pectin is often pre-mixed with an acid to get the pH below 3.5 which promotes gelling. Citric acid is often used, and plain lemon juice will also do the job. Lowering the pH is especially important when using ripe or over ripe fruit as these can be less acidic and also contain less pectin if we are talking about pectin containing fruit. After the pectin and sugar have been added, the jam shouldn’t boil for more than a couple of minutes as pectin is not very heat stable.

There are also a couple of claims found in jam recipes which I have been wondering about:

Skimming: Almost all recipes I have seen for jams call for rapid skimming of the foam which formes when the jam mixture boils. One explanation I’ve seen is that this is done to prevent growth of mold, as these apparently grow more easily in the foam. There are certainly airborn molds, but the bubbles in the foam come from the jam as it boils, so it’s been very hot and presumably sterilized. So I’m simply wondering if the whole skimming is about esthetics – which is is still a good enough reason to me (but then I wish the recipes could state that!).

Turning jars upside-down: One thing that has puzzled me for a time is why recipes recommend that the jars should be turned upside-down. I’ve googled and checked several books and have come up with a couple of explanations (but most recipes only state that it should or shouldn’t (!) be done, without giving any reason). The fun thing is that the suggested time for how long the jars should remain turned upside-down varies from 2 minutes to several hours when the jam is cool and has set.

  • One site claims it is done to prevent larger pieces of fruit from settling to the bottom. This does make sense, and in that case there is no reason to do it if the fruit has been puréed.
  • A blogpost commenter suggests that turning the jars upside-down for 5 minutes makes sure the inside of the lid gets sterilized too. The temperature of the jam at this time is probably somewhere around 95 °C, so it does seem reasonable that it might kill some molds residing on the lid. I’d give this a thumbs up. Any microbiologist who could confirm this?
  • Personally I have speculated whether turning the jars upside-down would allow water (or jam to be precise) to be drawn into the seal by capillary action and that this helps to make a perfect seal, but several sites emphasize that this should not be done to prevent the seal from being broken (these sites assume that a canner has been used – i.e. sterilizing the filled jars with lids in boiling water for 5 to 10 min). I’m not sure, but I wonder if there is a difference here between screw caps and glass lids with rubber bands?
  • A last reason to turn jars upside down would be to prevent the water evaporating from the hot jam to condensate on the lid. If the jars are left to cool upside-down for 10-15 minutes, but turned back before the jam sets this will prevent water to condense on the lid and drip back to the surface of the jam. This water could potentially mean better conditions for growth of molds. This theory is also supported by the suggestion found in old cookbooks where the jars are left to cool completely without lids to let the surface dry and form a skin, and then covered with a filter paper dipped in alcohol before tying them up with pergament paper and string.

The conclusion so far regarding turning the jars upside-down can be summed up as follows. You should chose of the three methods:

  • Cover with lid immediately and turn upside-down until cool enough to handle (~40-50 °C). Then return to upright position. This will prevent condensation of water on the lid, it might help create a better seal and it could possibly knock out some molds on the lid. The jam however will most likely not have set yet.
  • As above, with the only difference that you leave the jars upside-down until cool and set. This means that the air pocket will not be below the lid but at the bottom of the glass when turned back to the upright position.
  • Allow the jam too cool without lids until a skin has formed and the jars are cool enough to handle. This prevents condensation of water on the lid. Wipe the inside of the lids with the highest percentage alcohol available (but do NOT use denatured alcohol!) – typically it would be 40% or 60% – and screw on the lid before the alcohol evaporates. The skin formed will be less suceptible to growth of mold because there is less water present and because of the presence of alcohol.

Hydrocolloid recipe collection v.2.1

Wednesday, June 25th, 2008

An updated version of “Texture – A hydrocolloid recipe collection” is now available for download (version 2.1). The version includes corrections of typos, minor additions to the property tables plus an important update in the gelatin section and a recipe for agar filtration. Read on for details!

I’m grateful for feedback from several readers pointing out that the size of gelatin sheets is made to compensate for different bloom strengths. In other words, one gelatin sheet will gel a given amount of water, regardless of the size of the gelatin sheet. To the best of my knowledge, this convention seems to have been adopted by most gelatin producers.

All gelatin based recipes have been updated to reflect this and most of them now give the amount of gelatin both in grams (for a platinum type, 240 bloom gelatin) and in number of sheets. I’ve also included a formula for conversion between different bloom strengths. This formula differs from what has been published earlier (no square root), but by testing the formula for given gelatin sheet bloom strengths and weights I got better results by simply multiplying the mass by the ratio of the bloom strengths. If you know more about these formulas, please leave a comment or email me.

Checking the gelatin recipes I discovered that the recipe “Strawberry spheres” originally called for “Sosa vegetable gelatin” which is not gelatin but a mixture of carrageenan and locust bean gum which are dispersed with maltodextrin. Since the exact amount of carrageenan and locust bean gum are not known I’ve deleted the recipe (but I’m sure you could achieve the same coating effect with plain gelatin, perhaps a 3-4% solution to render it viscous so it will cling the the spheres).

Thanks to feedback from a reader there is also recipe now for agar filtration (based on a Spanish forum post). This works just like gelatin filtration, but is much faster. Apparently you get more or less the same results with regard to clarity, flavor and color.

If printing the collection, make sure the hydrocolloid properties table is rotated so it prints correctly. This table is presented in landscape format. The right most column of the first page is gelatin – if you don’t see it, try printing these pages again. The pages are optimized for printing on A4. If printing on Letter sized paper, make sure you check the “resize” or “fit to paper” option in your pdf reader.

Thank you for comments, corrections, recipes and other feedback! As always, I can be reached at webmaster a t khymos d o t org.

Hydrocolloid recipe collection v.2

Wednesday, May 21st, 2008

Texture – A hydrocolloid recipe collection
It’s a pleasure for me to announce that an updated version of the hydrocolloid recipe collection is available for free download as a pdf file (73 pages, 1.8 Mb).

What’s new?
Several new recipes have been added (now counting more than 220 in total), including recipes with cornstarch, guar gum, gum arabic, konjac and locust bean gum. All in all 14 different hydrocolloids are included (plus lecithin which technically isn’t a hydrocolloid). In each section recipes are now sorted according to the amount of hydrocolloid used. The appendix has been updated with tables for comparison of hydrocolloid properties, hydrocolloid densities and synergies. The perhaps biggest change is that all recipes have been indexed according both to the texture/appearance of the resulting dish and according to the hydrocolloid used. Let’s say you want to make spheres, this index will show you which hydrocolloids can be used (that’s right – there are other possiblities than sodium alginate) and list the example recipes.

A hydrocolloid can simply be defined as a substance that forms a gel in contact with water. Such substances include both polysaccharides and proteins which are capable of one or more of the following: thickening and gelling aqueous solutions, stabilizing foams, emulsions and dispersions and preventing crystallization of saturated water or sugar solutions.

In the recent years there has been a tremendous interest in molecular gastronomy. Part of this interest has been directed towards the “new” hydrocolloids. The term “new” includes hydrocolloids such as gellan and xanthan which are a result of relatively recent research, but also hydrocolloids such as agar which has been unknown in western cooking, but used in Asia for decades. One fortunate consequence of the increased interest in molecular gastronomy and hydrocolloids is that hydrocolloids that were previously only available to the food industry have become available in small quantities at a reasonable price. A less fortunate consequence however is that many have come to regard molecular gastronomy as synonymous with the use of hydrocolloids to prepare foams and spheres. I should therefore emphasize that molecular gastronomy is not limited to the use of hydrocolloids and that it is not the intention of this collection of recipes to define molecular gastronomy.

Along with the increased interest in hydrocolloids for texture modification there is a growing scepticism to using “chemicals” in the kitchen. Many have come to view hydrocolloids as unnatural and even unhealthy ingredients. It should therefore be stressed that the hydrocolloids described in this collection are all of biological origin. All have been purified, some have been processed, but nevertheless the raw material used is of either marine, plant, animal or microbial origin. Furthermore hydrocolloids can contribute significantly to the public health as they allow the reduction of fat and/or sugar content without loosing the desired mouth feel. The hydrocolloids themselves have a low calorific value and are generally used at very low concentrations.

One major challenge (at least for an amateur cook) is to find recipes and directions to utilize the “new” hydrocolloids. When purchasing hydrocolloids, typically only a few recipes are included. Personally I like to browse several recipes to get an idea of the different possibilities when cooking. Therefore I have collected a number of recipes which utilize hydrocolloids ranging from agar to xanthan. In addition to these some recipes with lecithin (not technically a hydrocolloid) have been included. Recipes for foams that do not call for addition of hydrocolloids have also been included for completeness. Some cornstarch recipes have been included to illustrate it’s properties at different consentrations. Recipes where flour is the only hydrocolloid do not fall within the scope of this collection as these are sufficiently covered by other cook books.

All recipes have been changed to SI units which are the ones preferred by the scientific community (and hopefully soon by the cooks as well). In doing so there is always uncertainty related to the conversion of volume to weight, especially powders. As far as possible, brand names have been replaced by generic names. Almost all recipes have been edited and some have been shortened significantly. To allow easy comparison of recipes the amount of hydrocolloid used is also shown as mass percentages and the recipes are ranked in an ascending order. In some recipes, obvious mistakes have been corrected. But unfortunately, the recipes have not been tested, so there is no guarantee that they actually work as intended and that the directions are complete, accurate and correct. It appears as if some of the recipes are not optimized with regard to proper dispersion and hydration of the hydrocolloids which again will influence the amount of hydrocolloid used. It is therefore advisable to always consult other similar recipes or the table with the hydrocolloid properties. The recipes have been collected from various printed and electronic sources and every attempt has been made to give the source of the recipes.

Since recipes can neither be patented nor copyrighted, every reader should feel free to download, print, use, modify, and further develop the recipes contained in this compilation. The latest version will be available for download from the static Khymos site and will also be announced here. I would like to thank readers for giving me feedback and suggestions on how to improve the collection. Feedback, comments, corrections and new recipes are always welcome at webmaster (a t) khymos ( dot ) org.

Help needed with densities of hydrocolloids

Wednesday, April 30th, 2008

Photo by Mel B via (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:

  1. 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).
  2. Put the empty container on the balance and use the tara function.
  3. Fill completely with water and weigh again. The difference gives you the exact volume (for water 1 g = 1 mL).
  4. Dry the container, put it on the balance and use the tara function.
  5. Spoon the hydrocolloid into the container, tap the side gently once or twice with the spoon and level off.
  6. Weigh the container again and write down the mass of the hydrocolloid.
  7. 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!

Khymos marketplace

Saturday, March 29th, 2008


I just wanted to let you know that the Khymos marketplace is operative. You can now shop books, hydrocolloids, thermometers, scales, whippers, syringes, tubes, squeeze bottles, knives and more directly from this site. I’ve selected products that should be of particular interest for amateur cooks and professional chefs that are intersted in molecular gastronomy, molecular cooking and popular food science. The marketplace is powered by

TGRWT #7: Cocoa frico with cauliflower cream

Sunday, October 28th, 2007


For this month’s TGRWT I wanted to make a cauliflower cream and serve it with something crispy. Considering the fact that cocoa and parmesan are also a good match I googled for parmesan crisps and found a nice recipe for “frico” – Italian parmesan crisps. The cauliflower cream was invented in the process of making it.

Cocoa frico
40 g parmesan, grated
2 t cocoa

Mix parmesan and cocoa. Divide into six portions on a parchment paper (use cake rings with a diameter of approx 9 cm). Bake for 4 min at 175 °C. Leave to cool. If made to thick, the fricos will be chewy rather than crispy.

Grate parmesan and mix with cocoa.

Transfer to parchment paper.

After baking the fricos look like this – let them cool for a couple of minutes before handle them.

If you want to make “baskets”, invert them over a wine cork or something similar.

Cauliflower cream
1/2 cauliflower, in slices
2.5 dL water
1.5 dL sour cream
2 t salt
1 t xanthan

Cut cauliflower in pieces and spread on aluminum foil. Bake for 40 min at 175 °C. Add water to cauliflower and pureé with immersion blender until smooth. Add sour cream, salt and xanthan and blend. Pass through a fine sieve and transfer to a 1/2 L whipper and charge with nitrous oxide. Note: To use up this portion of cauliflower cream makes you’ll have to make 20-30 cocoa fricos!

Caramelized cauliflower with nicely browned edges.

To serve, place frico on plate, fill with cauliflower cream and sprinkle with pepper.
The baskets were a little to large to grab, and impractical to eat with a knife and a fork. The flat half-moon pictured at the top of this post was easier to eat just using the fingers.

Verdict: A nice appetizer! Fricos have a strong parmesan flavour with a hint of cocoa. Aromas blend well, but the dish could need some kind of freshness added to it – Any suggestions?