This month’s TGRWT is hosted by Le Petite Boulanger, and the foods to pair are chocolate and meat. The recipe for the chocolate beef stock cream is inspired by the Iberian Ham Cream by Ferran Adrià/El Bulli (the recipe can be found on p. 21 in the hydrocolloid recipe collection). I used anis because it brings out the meatiness very well. After mixing in the olive oil I saw that the droplets were not properly dispersed. Addition of some lecithin which solved this problem.

Chocolate beef stock cream
100 g water
2 g beef stock powder
10 g chocolate (70%)
1/4 t anis, powdered
0.5 g xanthan
0.2 g lecithin
20 g olive oil
honey and chili oil to taste

Heat water to dilute beef stock and melt chocolate. Cool. Add xanthan and lecithin. Mix with immersion blender. Add olive oil. Mix until smooth texture. Sprinkle with chives.

Grilled pork tenderloin
pork tenderloin, cut in 3 cm thick pieces
oil
powdered anis
crushed garlic

Marinate meat with oil, garlic and anis mixture. Grill. Serve together with the chocolate meat broth cream.

Verdict: The chocolate beef stock cream has very meaty and almost nutty flavour. Honey is important to round of the otherwise slightly bitter taste of the chocolate. Chili oil gives it a bite, but can be omitted.

You can get an impression of the texture from this video:

I’m happy to finally announce the first edition of a recipe collection devoted mainly to hydrocolloids. Totaling 111 recipes, it’s available for download as a pdf file (29 pages, 433 kB).

Update: The collection has been revised and is now available for download (more than 220 recipe, 73 pages, 1.8 Mb).

The following text is from the introduction I’ve written to the recipe collection:

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 xanthan which is 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.

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 more than 100 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 espumas that do not call for addition of gelatin or other thickening agents have also been included for completeness.
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). As far as possible, brand names have been replaced by generic names. Most of the recipes have been edited and some have been shortened significantly. 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. 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, distribute and further develop the recipes contained in this compilation. The latest version will be available for download from http://khymos.org/recipe-collection.php and will also be announced at http://blog.khymos.org. Feedback, comments, corrections and new recipes are welcome at recipe.at.khymos.dot.org.

Martin Lersch
Oslo, August 2007

6. Learn how our senses work

Prolonged exposure to a flavor causes adaption and habituation, meaning that your brain thinks the food smells less even though it’s still present in the same amount. Back in 1953 Lloyd M. Beidler isolated nerves from the tongue of rats to study these phenomena. The nerves were situated in a flow-chamber through which aquous solutions with salty, sweet, acidic and bitter compounds could be flushed. The electric signal produced by the nerve was then recorded and fed to an amplifier and a plotter. Very simplified, the perceived intensity of the stimulus looked something like this (the curve is not to scale in any dimension and it’s my own qualitative interpretation of the data presented in the article):

After a short initial latency period a transient is followed by a slower prolonged decrement. There is even some nerve activity after the stimulus has been removed. What is interesting from a molecular gastronomy perspective is that the initial burst of taste quickly fades away – some call it fatigue or adaption. If the same stimulus is applied repeatedly, the maximum intensity of the initial taste burst decreases for each time it is applied. This is known as habituation and is illustrated in the figure below. As the time between stimulation of the receptor increases, the receptor recovers from the habituation and the intensity of the second stimulus increases to match the intensity of the first.

Adaption and habituation are also observed with odor. If you have used eau de cologne or perfume you might have noticed that you can smell it very well once applied, but after some minutes or hours you hardly notice it unless you sniff intentionally for it. The same applies for food.

Variation is the spice of life, and variation helps our senses to overcome adaption and habituation. More technically this has been referred to as “increased sensing by contrast amplification” which I think is a good way putting it. An illustrative example is Heston Blumenthal’s potato purée with small pieces of lime jelly (made with agar agar which is heat stable once it has set). The idea was that to avoid the adaption to the flavour and texture of the potatoe purée, small pieces of lime jelly would help “reset” the taste buds and thereby lead to an increased overall perception of the purée. I’m personally very fond of the variation provided by multiple component dishes. A curry sauce for instance is normally not served alone but alongside many other dishes: rice, dal, chicken/meat/fish, chutney, raita, nan, chapati, pakora, lime juice, salt etc. The different components contrast each other and help bring out the most of the meal.

Contrasts also help us smell better. When we sniff there is an abrupt change in the amount of air passing through our nose. More molecules pass the receptors and the sudden change in their concentration makes it easier to sense them. It has been shown that sniffing in fact gives an optimal odor perception.

Our senses are not unrelated, and there are many interesting articles illustrating this. For instance, adding color to make white wine darker or even red influences the perception of the wine aroma. Along the same lines, consider crystal pepsi which wasn’t a great success after all, probably due to the lack of color. With juice and soups it has been demonstrated that odors smelled through the mouth are perceived differently than those smelled through the nose. Similarily colors can either enhance of suppress the intensity of odors depending on whether they are smelled through the nose or through the mouth.

There are a number of odor-taste interactions. For example, through repeated pairing with sugar, odors become “sweeter”. We become better at detecting sugar solutions if strawberry aroma is added to them, but worse if ham aroma is added. And you shouldn’t be to surprised that both perceived and imagined odors influence taste (that’s right – think of strawberries, and sucrose will taste sweeter!). Heston Blumenthal uses this in the savory ice creams he makes. We associate the cold and rich mouthfeel of ice cream with something sweet, and this influences our perception of the flavour, making it sweeter. In general, the “sweeter” an odor is perceived, the more it enhances tasted sweetness and the more it suppresses sourness. Preliminary experiments suggest that even pure tastants have a smell.

A thing to consider when eating is that our body position influences olfactory sensitivity. And don’t forget that your emotional state also has an effect on the olfactory perception. Emotionally labile people are more sensitive to certain smells and less sensitive to others.

The examples of how our senses are not independant has some practical implications for cooking and eating:

Presentation is paramount, and it is worthwile to consider the art of food presentation. There is a lot to learn from food photography blogs and food blogs with good photos: still life with…, matt bites, 101 cookbooks, la tartine gourmande too mention but a few. Also check out the pictures submitted to the monthly food photography blogging event does my blog look good in this (google DMBLGiT to find out which blog hosts this month’s event).

Taste, smell, texture, mouth feel, temperature and appearance will all contribute to the overall experience when eating and drinking. But also the room, the atmosphere and the people present have an influence. I have previously mentioned the five aspects meal model which has been developed for restaurant settings and takes all of this into account.

Many of the ideas found in this blog post can be expressed in appetizers. With small, well prepared amuses bouche there is variation with every bite, creating excitement and anticipation.

And remember that average food eaten in the company of good friends while you’re sitting on a terrace with the sun setting in the ocean will taste superior to excellent food served on plastic plates and eaten alone in a room with mess all over the place.

Update: I submitted the picture of the cherries in the heading to the monthly “Does my blog look good in this” (or DMBLGIT for short) photo competition for food blogs – and guess what – the picture was the winner of the August 2007 round. This is a great honour, because there are so many good photographers out there with food blogs. Click to view the complete gallery of the August 2007 round.

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Check out my previous blogpost for an overview of the 10 tips for practical molecular gastronomy series. The collection of books (favorite, molecular gastronomy, aroma/taste, reference/technique, food chemistry, presentation/photography) and links (webresources, people/chefs/blogs, institutions, articles, audio/video) at khymos.org might also be of interest.

Previously I had only tasted sliced strawberries with a fresh coriander leaf, just as a very basic illustration of this pairing. I must say I liked the combination, even though it’s dominated by coriander (or cilantro as it’s called in North America). But I figured that once the strawberries are processed into a dish, one would probably have to reduced the amount of coriander, so I did quite a lot of tasting as I proceeded with this combination for the third round of “They go really well together” (previous rounds: TGRWT #1, TGRWT #2). And I was surprised how well the coriander came through, even when using as little as 0.5 g! So start with a small amount of coriander if you decide to try this. Several have commented that they’re not to fond of coriander or the strawberry/coriander combo, and I wonder if this could be because they used too much coriander?

Anyway, I decided to go for a warm strawberry foam and be carefull with the amount of coriander. I started out without sugar, but found that sugar was essential for the strawberry coriander pairing (unless I would have taken it all in a savory direction like M did). Balsamico vinegar emphasizes the strawberry aroma and adds acid which I find important. If you plan to prepare this dish, I would suggest to add coriander, sugar and vinegar a little at a time, just to make sure it fits your taste.

Foamy strawberries with coriander and balsamic vinegar
200 g strawberries
0.5 g fresh coriander leaves
30 g sugar
14 g balsamic vinegar
150 g water
1 g xanthan

Make a purée of strawberries, coriander, sugar and balsamic vinegar with an immersion blender. In a separate container, mix water and xanthan using the same blender and add to the strawberry mix. Xanthan gives a viscous solution and helps retain the bubbles. The nice thing with xanthan is that it dissolves in cold liquid and requires no heating, but is stable at higher temperatures if you should want to heat the mixture. The immersion blender can be used to whip in some air, but for an even more airy texture, use an ISI whipper (many models available: cream, easy, gourmet, dessert, thermo) and charge with a cream charge (N₂O). Important: you must filter out ALL the small stones from the strawberries using a cheese cloth or a towel, before transfering the mixture to the whipper, as these will clog the nozzle of the wipper (mine got clogged!). For a warm foam, heat the whipper in a water bath at 60-70 °C, but only do this if you have the ISI gourmet or thermo whippers which are designed for higher temperatures.

Verdict: I was very satisfied and my wife liked it too! There’s a good balance between the strawberry and coriander aroma. Sugar rounds of the taste and the balsamic vinegar balances the sugar with it’s tangyness. I served the foam warm together with plain vanilla ice cream – delicious! At room temperature the sugar/acid balance was perfect according to my taste, but when served warm the foam was perhaps a little on the sweet side (which comes as no surprise as sweetness decreases when lowering the temperature).

Closeup of a larger air bubble below the surface! Who can resist to taste this?

A while back I saw Evelin’s post on how to make marshmallows for Valentine’s day, and I knew immediately that I would like to give it a try. With TGRWT #2 coming up (that’s the second round of the food blogging event “they go really well together”), I thought I’d make marshmallows with a banana parsley twist. I figured that the banana flavour should fit very well with the soft and airy, yet elastic texture of marshmallows. And I was very curious to find out how the parsley would fit in!

Marshmallows were originally made using egg whites and the sap of the root of the marshmallow plant which were cooked with sugar and whipped into a foam. Today the marshmallow sap and egg white have been replaced by gelatin which is a protein produced from collagen in the connective tissue of animals. Proteins are good at stabilising foams (see previous post on how to make a Vauqelin). Addition of sugar increases the viscosity which stabilizes the foam even more. In marshmallows this is taken to an extreme. A large amount of gelatin is added to a concentrated solution of sugar (and corn syrup). This mixture is whipped for about 10 minutes to incorporate air and to break up larger air bubbles into smaller ones.

The first challenge was to find a suitable recipe. There are recipes that call for sugar only whereas others call for sugar and corn syrup (this recipe also gives a hint on how to substitute fruit purree for water). Corn syrup is added to prevent crystallization. Also some recipes use egg whites which are said to give a lighter texture. I decided to go for a simple recipe and used only sugar. I would also need to substitute mashed bananas for some of the water. Addition of parsley shouldn’t need any special adjustments of the recipe. I ended up with a recipe which is more or less a mixture of all these.

If you’re unsure about the process of how to make marshmallows, Cooking for Engineers has a detailed step-by-step description with pictures. The pictures at the end of this post should also give you an idea of what the texture is like. If you’re still lost, check out this video (the first in a series of six) on how to make mango marshmallows.

Banana marshmallows with parsley
65 g water
200 g sugar
10 g gelatin, bloomed in plenty of water
65 g banana, mashed
parsley (see comment below on why it shouldn’t be finely chopped)

Bring water and sugar to boil while stirring. Remove from heat when temperature reaches 110-115 °C (230-240 F). Add bloomed gelatin sheets and mashed bananas. Whip for 10 minutes (much longer than you think!). Add parsley to taste. Grease a pan, sprinkle with powdered sugar and spread mixture in pan. When set, invert pan on a surface dusted with plenty of powdered sugar and starch. Cut up in desired pieces and coat every cut surface with powdered sugar and starch.

What about the taste? I tasted the mixture before it set and was surprised by how well the banana and parsley blended together. To be honest, it tasted really nice! The next day however, after I had cut the marshmallows into squares, they tasted quite different. The parsley aroma had changed significantly and was more reminiscent of hay, so I was quite disappointed. The banana flavour was still intact, but I felt it was somewhat weaker than in the fresh mixture. Nevertheless, some guests I served it to reached out for both a second and a third piece of my banana marshmallows with parsley, so they couldn’t have been that bad after all. Perhaps it had to do with the texture which was really, really nice!

It turns out that the hay like off flavour of parsley is well known and described in the litterature! See for instance “Hay-like off-flavour of dry parsley” or “Evaluation of the effect of drying on aroma of parsley by free choice profiling”. The molecule responsible for the hay-like off flavour is 3-methyl-2,4-nonanedione. And apparently vacuum-microwave drying of parsley gives less hay flavour.

It is suggested that the hay like off flavour is formed by oxidation of unsaturated fatty acids or polyenes. As a consequence, I would suggest not to chop the parsley (or at least leave large pieces intact) to limit the exposure to oxygen. After parsley has been added, the mixture should be mixed carefully to keep the leaves intact. I used finely chopped parsley when I made the marshmallows in order to increase the release of volatile compounds from the parsley, and I think this is the main reason why I got the hay like off flavour.

Whip until you get a thick, creamy texture.

Spread in a pan greased with butter/fat and sprinkled with powdered sugar.

For the food blogging event They Go Really Well Together (TGRWT #1) I decided to used baked garlic. Baking gives garlic a slightly sweet, mellow taste and I figured this might work well with the soft texture of an espuma. Just make sure you get fresh garlic without green sprouts – they will give a bitter taste.

4 cloves of baked garlic (baked whole, 30 min @ 150 °C)
3.5 dL strong coffee
30 g sugar
40 g chocolate (70% cocoa)
ground cardamom
3.4 g gelatin (= 2 sheets)
1.5 dL heavy cream (38% fat)
1 iSi cream charger

Mix garlic cloves and coffee with blender or hand-held mixer. Add chocolate, a pinch of cardamom and heat while dissolving sugar. Stir in pre-soaked gelatin. Cool, add heavy cream, sift through fine mesh to remove remaining pieces of garlic and fill 0.5 L iSi gourmet whipper. Charge with 1 cream charger and leave in fridge over night. Serve with a drizzle of instant coffee.

How it tastes? In the finished espuma served cold, the first aroma noticed is coffee accompanied by a sweet taste on the tongue. This is followed by a faint chocolate aroma which then gives way for an aftertaste dominated by garlic. It’s quite surprising and the aromas blend well together. I used 30 g of chocolate, but I’ve increased it to 40 g in the recipe since the cocolate aroma was a little weak. As for uses, I think it would go well with a steak for instance. If used as a dessert I would perhaps reduce the amount of garlic to 2 or 3 cloves so as not to overwhelm the guests (unless they frequent the restaurant Garlic & shots in Soho, London where even the beer is served with garlic!).

Were you told by your mom to chew each mouthful 20 or 32 times before swallowing? Her rationale was perhaps to prevent you from choking. But it turns out there is a link between chewing (or mastication) and release of aroma molecules. A group of French researchers have studied model cheese systems with varying hardness (J. Agric. Food Chem., 2007, 3066, 10.1021/jf0633793). Their key finding was that in hard cheese, more aroma is released, and it happens at a faster rate than in softer cheeses. It is slightly counter intuitive, because one would expect that volatile aroma molecules would have a harder time escaping from a hard surface than from a soft surface. The reason however is that when chewing a hard cheese our chewing pattern automatically adopts and we chew more intensely. Furthermore a hard cheese will break down into several pieces when chewed, resulting in a greater surface area from which the aroma components can escape into the air.

(Photo by kurafire at flickr.com)

Heston Blumenthal has investigated how sound affects chewing, but I didn’t know that sound was so important for how we perceive the taste of apples. Studying particularily crisp apples, named Jazz apples, researchers found the following:

Professor Povey said, “When you munch a Jazz apple you create pulses of sound containing large amounts of ultrasound which our brains interpret differently from ordinary sounds such as speech. The pulses are so intense that if they were sustained as a tone, they would destroy our hearing.”

“It appears that ordinary hearing is short-circuited somehow and the greater the number of pulses of sound, the crisper we think the food is. Ultrasound is sound that is beyond the range of normal human hearing but it helps shape the noise into pulses that sound quite different.

“Our group of subjects were culturally diverse but all were able to identify crispness similarly. So perhaps there is a genetic disposition to the appreciation of crispness which has evolved as a sign of freshness in food.”

In a comment to my post on making carbonated fruit the iSi way, JoJo at eat2love made me aware of a company, FizzyFruit, that actually sells carbonated fruit in pressurized containers. The fruits currently available are grapes, honeydew and cantaloupe. Turns out that their homepage features some recipes by – surprise, surprise – Homaru Cantu! Here are some of the recipes:

Proscuitto and melon
150 g carbonated melon
12 slices proscuitto ham
1 dL balsamic vinegar, frozen, shaved to snow
salt
olive oil

Wrap melon pieces with proscuitto, season with salt and drizzle with olive oil. Scatter balsamic “snow” over the top just before serving.

Champagne and Crab
150 g carbonated grapes
350 g picked crabmeat
1/4 bunch of chives, chopped
1 diced shallot
1 orange, juiced and zested
1/2 dL mayonnaise
1/2 dL fennel, shaved thinly
salt

Toss crab with shallot, fennel, mayonnaise and orange juice/zest. Season with salt and leave in refridgerator for 1 hour. Add carbonated grapes, toss with crab mixture and chives. Serve immediately.

Orange Sangria
2 L fresh squeezed orange juice
150 g carbonated fruit (grapes, melon)
8 sprigs of crushed mint
5 dL of crushed ice

Combine ice, orange juice and mint. Add carbonated fruit and serve immediately.

Fresh Fruit Trifle
150 g carbonated fruit (grapes, melon)
2.5 dL fresh whipped cream
1/2 vanilla bean scraped

Add vanilla bean scrapings to cream and whip until stiff peaks are formed. Layer carbonated fruit with whipped cream and serve immediately.

Ants on a Log
150 g carbonated grapes
2.5 dL of chunky peanut butter
4 long ribs of celery

Rinse and dry celery. Fill celery with peanut butter. Stud the celery with the carbonated grapes. Serve immediately.

(The recipes were made generic and converted to metric units)

Based on some googling of espuma and foam recipes (including Ferran Adria’s coffee espuma), I figured that the following should work:

2 dL coffee
2 sheets of gelatine
3 dL heavy cream
sugar/vanilla sugar

Soak gelatine in cold water. Strain. Dissolve gelatin sheets in the hot coffee and stir in sugar while heating. Cool. Add heavy cream. Filter through a fine meshed sift (just in case there should be any undissolved sugar, gelatin or particles) into a 0.5 L iSi gourmet whipper. Screw on top and charge with a cream charger. Shake 2-3 times and leave in fridge for a couple of hours. Hold whipper upside down, shake once to displace mixture towards the nozzle in case it is stuck and dispense. Texture is soft and silky. Tastes delicious!

Some more chemistry: The cream chargers contain dinitrogen oxide (N₂O) which is less polar than carbon dioxide (CO₂), and hence more soluble in fat (such as heavy cream for instance). Another reason why carbon dioxide is not used in this recipe is probably that when it dissolves, some carbonic acid is formed which could curdle milk based products if pH drops to much and also influence taste (but carbonated milk has actually been marketed!). The idea of using dinitrogen oxide for soda/beer has also been explored.