Recipe development - Millefeuille of duck

Those of you who are eagerly clinging to my every word may have noticed that I have been foaming lately. I have been (and still am) trying to get my head around foams and writing some rather boring posts about that. How can I make different kinds of foam? I have been following a good class at http://www.chefsteps.com/. This website has a lot of really nice stuff. But nice as it is to read about it, I want to really get to grips with it and develop and understanding of what works and what does not work, so I am testing things out. And there is a specific reason for my foaming. I need a hot duck and orange flavoured foam with the consistency of shaving foam for a recipe I have dreamt up and want to develop.

Millefeuille of duck.

As most of you will know, millefeuille is as dessert consisting of alternating layers of crispy pastry and some form of cream / pastry cream. The picture above is from one we had at the Savoy Grill in London, but it was not served with a rubber duck. I added that "in post".

When we ate at Noma in Copenhagen a few years back, we had one course consisting of crispy chicken skin. It was like a piece of crisp bread, very thin, delicate and crispy. As I was reading about foams a while back I thought "What if I combined equally crispy duck skin with a rich foam?" I love the combination of different textures, it adds a whole new layer to food. Oranges goes well with duck and adds a fresh note. The foam should taste of duck and oranges. And there should of course be duck meat as well.

So this is my vision:

• A rectangle of utterly crisp duck skin at the bottom. 
• A layer of a lush, creamy foam tasting of duck and oranges on top of that (a bit like if you make a sauce from duck stock and flavour it with oranges, but as a creamy foam). 
• Another rectangle of crispy skin.
• Duck meat (breast and/or confit of leg) on top.
• Possibly a duck demi-glace somewhere, either on the plate or on top of the meat.

So I need to work out how to do the foam and how to make the skin crispy and nice. I envision doing the meat sous vide. So this is what you will find in my blog for the oversee-able future. Foams and crisp skin. Wish me luck!

And if anyone have ideas, I am open to suggestions.

In my lab - Foams, part 4, Lecithin

Lecithin is a fatty substance that occurs naturally in lots of animal and plant tissues. It is the lecithin in egg yolk that makes the yolk work as an emulsifier. It also works as a foaming agent. According to this page it is most often used at a ratio of 0.25% - 1%. Let's try it out.

I added 1g lecithin to 300 grams of water. That makes 0.3% of lecithin.

I poured this into a wide, low container and whipped it using an immersion blender. Since the goal here is to add air, I held the blender so that half of it was over the liquid and half of it in the liquid. This may be a bit messy, so you may want to put a cloth or something over the part of the container where the action is. This resulted in a bit of foam that could be spooned out onto a plate, but nothing celebrate, really.

Same thing now, but with 3g of lecithin. This makes 1% of lecithin in the
water. this time there is much more foam, and it seems to be stronger as well. When spooning this out I get a good height on the plate. The foam seems quite stable. Bubbles are of medium to large in size, so the foam is quite coarse. It also feels quite dry and is very light. This is perfect for what is known as an air. The liquid used to make this must have a really strong taste because there is very little of it, the foam is mostly (normal) air. This can be used to add subtle flavour nuances to a dish without drowning the dish in sauce.

So the foam we created above was quite dry. There is very little of the liquid
in it. If we want it to be wetter and containing more liquid, we need to thicken it. I will try to add Xanthan. According to some sources I have found, Xanthan is typically used in a ration of 0.1% to 0.5% to do this. So I mix 300g of water with 3g of lecithin and 0.3g (0.1%) of Xanthan. The resulting foam is more heavy and wetter containing more of the water, but also, because of that it cannot support itself and sits flatter on the plate. It seems quite stable, though.

Let us see what more Xanthan does. 300g of water, 3 grams of lecithin and
1.5g (0.5%) of Xanthan. The liquid is quite thick before whisking, and the resulting foam is very wet, but it is so heavy that it just sits on the plate as a shallow, airy mass. Also, the bubbles seem to be a bit bigger now. Not very exciting.

But what would this be like using a whipping siphon? I mix 300g of water, 3g of lecithin (1%), some red colouring and 1g (about 0.3%) of Xanthan. I mix this with the immersion blender, pour it into the ISI whip, charge with one canister of N2O and shake vigorously. This gives me a quite fine foam with small bubbles, but it is not very strong. Since the foam is quite wet, it cannot hold its shape. It seems quite stable, though.

I try to double the amount of lecithin, using 6g. The foam i a bit firmer, managing to stay in a lump in stead of just floating out. Nice wetness, but at this concentration I think I can start tasting the lecithin, and we do not want that.

What if we just add another charge to the same siphon now and give it another shake? The foam seems a bit stronger having slightly more height, but I really do not think this is the way to go. I also try adding no Xanthan, only lecithin as we did when whisking up that air. In the siphon that does really not work at all. No foam, just squirting liquid all around.

So let us go over board with the Xanthan. 300g of water, 3g of lecithin and 3g of Xanthan. This time the goo that I pour into the ISI whip is quite thick. When dispersing, I get a nice, wet foam with very fine bubbles. It really has a good mouth feel. It also holds a bit of shape. I sort of like this one. Almost like a foamy sauce.

As a last try, what if we did the same, but without the lecithin? With only 1% Xanthan? Wet slime with bubbles and not really any hold to it.

So I think the conclusion for lecithin so far is:

1% of lecithin for a good "air". Perhaps with a tiny amount (0.02-0.05%?) of Xanthan to give it more wetness, but not so much as to collapse the bubbles. Whisked using an immersion blender.

1% of lecithin and 1% of Xanthan for a very light creamy foam using a siphon.


Below: Pan fried cod with carrots and lemon air.

In my lab . Foams, part 3: Whipping cream in a siphon

So let us make some foam. Here is one of the most widely used foam. Whipped cream. We have all made that. whipping cream in a bowl, add sugar, whisk it until it is finished. Easy. In whipped cream it is fat that sticks to the bubble walls insulating them from each other. Actually, in whipped cream there are both fat and proteins. cream is an emulsion with fat suspended in water (and other stuff). The proteins act as an emulsifier covering the fat so that the fat droplets do not come together and ruin the emulsion. As we whisk, we strip away proteins from the fat droplets while the whisking motion also adds air. The naked parts of the fat droplets stick together to form networks that now cover the air bubbles. In that way the fat droplets work as a foaming agent.

I used the work easy up there. But as any keen cream whisker knows, it is also easy to whisk too much and end up with over whipped cream and even butter. One normally wants a silky smooth product. Actually, one trick to get an even smoother cream is to add just a tiny bit, perhaps 0.1% of Xanthan to the cream before whipping.

I have a brand new whipping siphon, and I am hoping to be able to make foams with it. And these things were actually originally made for whipped cream, so let's try it out. It works like this:

• Mix whipping cream and sugar. (And Xanthan if you want to)
• Pour into the siphon
• Charge with N2O
• Shake
• Disperse

Easy. But over whipping is still a problem. And in the siphon there are several ways of over whipping. If there is too much gas in relationship to the cream, it may over whip. If you shake it too many times it may over whip. So you need to work out how much cream, how much gas and how much shaking works with your siphon. But once you know that, you can repeat that over and over again and have the same result every time.

Here is what I found works in my world. Here in Norway, whipping cream normally comes in cartons of 1/3 litres. So I mix that with the amount of sugar I want and pour it into my siphon. I am using a 1/2 litre siphon. There are more sizes. ISI makes 1/2 and 1/1 litres, and the amount of cream, gas and shaking will be different between them.

So 1/3 litres into my 1/2 litre siphon, charging with one canister of N2O. I read somewhere that one whole canister may be too much for this. If you squeeze the lever half way, you can let some pressure out. I have found that a light squeeze (before placing the siphon upside-down) for 3-4 seconds works for me. 

How many times should I shake it? I tried in intervals of three and dispersed a bit after each time. Here is the result.

It is difficult to see details in the photo, but three shakes was obviously too little giving me slightly thicker but still fluid cream. Number two, after three more shakes, looks like whipped cream, but is a little loose. Number three, after nine shakes total, is the way I like it. After three more shakes, it started to be over whipped, too stiff and not having the smooth surface that I like. The picture to the right shows number three and four.

So that is my recipe for a Norwegian carton of whipping cream in a 1/2 litre siphon. Mix with sugar + 0.3 grams Xanthan. Add to siphon, shake 8-9 times. Disperse.

The great thing about doing it in the whipping siphon is that it is repeatable without the risk of over whipping once you have found the formula, it store well in the siphon in the fridge and the whipped cream is basically fresh each time you disperse it.

Yummy.

In my lab - Foams, part 2: Sience

So what is foam? Foam is gas suspended in liquid. The gas may be air, CO2, N2O or just about anything, but these are the ones you will usually find. Whipped cream contains air. Foams created with a whipping siphon contains N2O. Carbonated sodas like Coke (yes, it is a foam according to the definition of gas suspended in liquid) will contain CO2. So, sodas and beer are foams, too. And, from what I read, so is bread. Bread is a set foam. I do feel that this is stretching is a bit, but who am I to judge?

Basically foam is like an emulsion between liquid and gas. If you mix oil and water, they will soon start to separate with the oil going to the top and the water going to the bottom. But if you add an emulsifier like egg yolk in there, some components (lecithin) i the egg yolk will make the two stay together.

So foam is an emulsion between liquid and gas, and as such it needs an emulsifier or foaming agent to be able to stay as a foam and not go back to liquid and gas separated. The foam forms when molecules from the foaming agent start coating gas bubbles forming a network that prevents the individual bubbles from coming together to form bigger bubbles. If you add detergent to water and then add air by whisking, the air that is blended with the water will stay there as bubbles because the foaming agent in the detergent keep the bubbles separate. Now, in this kind of foam the water actually fall downwards and out of the foam, making the foam very light and dry and thin. If you wanted a thicker and wetter foam, you could do that by thickening the liquid with for instance Xanthan. This is called stabilising the foam, and Xanthan is a stabiliser in this respect.

So you need a foaming agent and possibly a stabiliser to thicken the foam. In addition, you need to add the gas. This may be done by whisking, blowing air into the solution or suing a whipping siphon to add gas. Natural foaming agent may be protein (for instance in milk), fat droplets (in whipped cream) lecithin (from egg yolk or soy) etc. The stabiliser may be anything that makes the liquid thicker, such as, as I mentioned, Xanthan that I wrote about in an earlier post here. Ordinary gelatin is great for foams because the proteins both act as a foaming agent and it makes the liquid thicker, so it is also a stabiliser. But since gelatin melts when heated, it can only make cold foams. If you want to make hot foams, you can for instance use lecithin as the agent. This will make a quite thin and delicate foam, so you may want to thicken it with Xanthan which also works when heated.

Basically what I want to find out is which foaming agents to use when, what kind of foams they make and how I can change the appearance of that foam with stabilisers and the like.

Here is a good page on foams:

http://www.modernistcookingmadeeasy.com/info/modernist-techniques/more/culinary-foams-technique

In my lab - Foams, part 1

I have a food geek friend who does not read my blog because the posts in here are too long. Laziness, that's what it is. So I have decided to please him by doing more and SHORTER posts for a while. I will be spending a bit of time researching some modernist techniques, and I will hold you updated on the proceedings in SHORT and frequent posts. The first topic will be foams.

Foam has become one of the defining icons of Modernist Cuisine. Foam in all shapes and sizes. My Modernist-doubting friends hate it. As one of them told me after eating in a restaurant steeped in modernism: "There was foam on everything! Terrible!" This series of posts will make them foam at the mouth. Pun intended.

I think foams are wonderful elements in dishes. As a slight kiss of a taste in a thin "air", almost as a very light sauce or like a light puree in thicker versions. As a small element to complement something else, or as the main event on the plate. Often I consider foams as being quite equal to sauces. And, mind you, in many cuisines there are sauces on just about everything, but no-one complains about that, do they. I think it is all about what you are used to.

But what are foams? How do they work? How can I control the thickness, density and stability of them? That is what I want to find out. In the next series of (SHORT) posts, I will try to research this.

I actually have dreamt up a new dish that I do not know how I am going to make and it contains a foam. I will be working towards finding out how to solve that. There are also other elements in this dish that I will need to research later on. So there will be a number of posts coming your way reporting on this.

SHORT posts.

So read them!

Onion fluid gel

Ok, so I remembered it wrong. And had to improvise. But it actually turned out quite good. There is a video on youtube called The Fat Duck - Masterclass (Part 1 of 2) that I had seen a while ago, and they mentioned an onion fluid gel. As we did our shopping for the Sunday dinner, I wanted to try that with the meat we bought. But I could not remember the details. I knew they cooked onions sous vide and then made a fluid gel out of that. So I bought two red onions. As I came home, I found the video and the spot where the chef says "and we cook these sous vide for 96 hours". And this was on the Saturday with no 96 hours to be had. So I sliced the onions thinly and sealed them with a bit of olive oil and some baking soda in a ziplock sous vide bag. Since I do not have a chamber vacuum machine but one that sucks the air out from the edge of the bag, I cannot use it when there is liquid in there. One solution to that is to freeze the liquid, but this time I chose the ziplock bag using water immersion to try to get as much air out as possible. This, of course, leaves a bit of air in there causing the bag to float, especially as the air is warmed by the heat, so it has to be weighted down. Bit of a nuisance, but it works.

Why the baking soda? Just a whim. Baking soda makes stuff more alkaline. That makes the Maillard reaction accelerate. This reaction is responsible for the dark colours on browned meats, but it also gives rise to a wealth of flavour compounds. Normally this does not start to happen until the food hits 100-120 degrees, but perhaps the added baking soda would help. I do not know, but I tried. Did it help? I still don't know.

I cooked the onions in the water bath at 85 degrees for as long as I could before dinner on Sunday. That turned out to be a out 24 hours. When taking the bag out, the contents was quite brown, and quite a bit of liquid had gathered. I should have taken a picture, but I forgot. Anyway, I strained the liquid and also pressed some of the soft onions through a sieve. This gave me 170 grams of dark fluid. I gave it a simmer and added some salt and pepper and 1 gram of Gellan. Than comes out at about 0.6%. This set into a quite firm gel. After running my immersion blender through it, it came out as a rather thick and very tasty fluid gel. it may be that 0.6% Gellan was a bit much, perhaps 0.4 would be better. The fluid gel turned out as a quite thick pure. I will be looking more into fluid gels at a later stage.

But it was good, and that is the most important thing. 

In my lab - Xanthan gum

So I am trying to learn about Modernist Cuisine. I am currently (and will for some time be) reading the gigantic 5 volume book Modernist Cuisine as well as numerous blogs and articles on the web. So I am getting all the theory, but to learn something, you really need to get your hands dirty. Well, that is perhaps not a term that works well in the kitchen, but you know what I mean. Try things out myself. Do stuff. See what happens. So I will be doing a series of posts where I investigate modernist techniques and ingredients. I will do this first and foremost to learn from it myself, but if other find it interesting as well it will be an added bonus.

I started getting interested in modernist food several years ago. I owe this interest to a Canadian friend of mine who lived here in Oslo at the time. So we talked about it and even tried out a few things, but it sort of died away. We had no real knowledge and we did not really know where to get it. But what I did manage to do was to buy stuff. I am quite good at buying stuff. So I ended up with a few cans of powders in my basement, tried to use it a couple of times without much success and then the spark died. Until now. Time to dig up those strange products again and see what I can do with them.

First out is my can of Xanthan gum. I got all my cans of mystery from Texturas back then. This is a company owned by Ferran Adrià, the famous chef who used to run the restaurant ElBulli and his brother selling modernist ingredients. They market their products with special brand names, so their Xanthan gum is called Xantana. You can find their website here:

http://www.albertyferranadria.com/eng/texturas.html

So, Xanthan gum, what is it? According to Wikipedia

Xanthan gum (/ˈzænθən/) is a polysaccharide secreted by the bacterium Xanthomonas campestris,^[2] used as a food additive and rheologymodifier,^[3] commonly used as a food thickening agent (in salad dressings, for example) and a stabilizer (in cosmetic products, for example, to prevent ingredients from separating).

So it is a thickener and stabiliser. It makes liquids thicker. According to Nathan Myhrvold, the author of Modernist Cuisine, it is one of the most versatile food additives developed over the past years.

"Xanthan gum is one of the most useful food additives around; it is effective in a wide range of viscosities, temperatures, and pH levels. It is easy to use, has no taste, and generally works quite well. And it can thicken liquids at extremely low concentrations —as little as 0.1% by weight can yield a thick liquid, and 0.5% by weight can make a thick paste..."

Time to do a bit of testing. I measured up 200 grams of cold water and slowly added 1 gram of my Xanthan while whisking. I ended up with lots of small lumps. By the way, this is how I like to weigh small amounts on my fine scales, using a paper to place the powder on. This makes it easy to add it to the food, and also all of my cups or other stuff is too heavy for the scales.

So whisking by hand in cold water is not a good idea. I repeated the same thing, but this time using my Bamix immersion blender. This worked out well. The powder was fully mixed with the water, but the blender added quite a lot of air bubbles that did not seem to go away by itself. After 30 minutes they were still there (or most of them). I tried sifting it 4 times. This removed some of the bubbles, but the mixture still had quite a lot of them.

Viscosity wise, the Xanthan had made the water thicker. A bit like saliva. This was 0.5% Xanthan by weight. According to Myhrvold, 0.5% could make a thick paste. This is not a thick paste. Could it be that the Texturas brand is weaker in any way? I need to buy another brand to test as well.

Next up, simmering water. I added the same concentration of Xanthan to simmering water, whisking by hand. This time there were no lumps. The powder mixed fully, and because I only mixed by hand, the amount of air bubbles was much less. The thickness seemed to be the same as with cold water. I added another gram of Xanthan powder to the same batch making a 1% mix. This gave me a rather thickish result, like a weak gel. I also added a little bit of yellow food colouring to be able to see it better and spooned a bit of it on a plate, see picture left. As you can see, it stays as a sort of low lump on the plate. It is very clear, but yo can also see some bubbles.

I then tried the immersion blender in this 1% solution. This gave med a very frothy solution with lots of well sized air bubbles. The colour was now quite opaque because of the bubbles. This can be used as a foam, but it feel kind of heavy in the mouth and a bit slimy, not as a light foam. 

But how should one mix Xanthan in a cold liquid? I tried mixing the powder with sugar and added this to the cold water. I made sure the powder was completely distributed and blended with the sugar. The outcome was perfect. Whisking by hand left no lumps. So we need to separate the powder into individual specs as much as possible before adding it to the water. This way it will not lump together. I also found that if the powder is first mixed with oil and the oil is then mixed with water, the final mix is lump free. 

I had some chicken stock in the fridge. I divided it in two times 2 dl and added 1.5 grams (0.75%) of Xanthan to one of them while simmering. This gave me a nice sauce thickness. The I started adding corn starch to the other batch until I had about the same consistency. That took about 10 grams. Since it took so much corn starch to thicken it, that one came out much more cloudy and opaque than the Xanthan one. My broth was not quite clear, and the Xanthan batch is as clear as the broth. Also, the Xanthan one tastes much more of the broth. It seems that the corn starch one has lost more flavour than I had anticipated. Since the amount of Xanthan is so small, neither taste nor clearness has suffered. So thickening with Xanthan keeps the taste better and also will give you a clearer sauce or whatever you are making.

We are having a salad with dinner tonight. I make two vinaigrettes, both at 3:1 totalling 1 dl. To one of them I add 0.3 grams of Xanthan in the oil before adding the Balsamic vinegar. Both are mixed using the immersion blender. After a couple of hours, the one without the Xanthan is clearly dividing into vinegar at the bottom and oil on top. The one with Xanthan seems to stay well mixed and is slightly thicker. Nice! But as Xanthan does not swell in oil, but only in water based liquid, I will guess that thickening oil based liquids does not work.

Also, for the same dinner I cooked the meat sous vide and then seared it in the pan. After searing I deglazed with water and a bit of red wine vinegar, salt and pepper and added about 0.75 grams of Xanthan. This turned out beautifully, the Xanthan thickening the gravy to a nice, thin sauce consistency.

Food from the Fat Duck - Hot and Iced Tea

Finally I got round to it. Heston Blumenthal's Hot and Iced Tea. This is one of his most famous concoctions, even though it is not really a dish. It is more like a small comment or minor happening that he uses as an overture to the sweet portion of the menu. For the uneducated out there who do not know what this is all about, let me enlighten you. At the Fat Duck restaurant, Heston Blumenthal serves a cup that contains hot tea in one half and iced in the other, divided vertically with no visible divider in the cup. Here is a video on youtube showing Heston doing this.

http://www.youtube.com/watch?v=N7i4F6vqOlc

I know this will be fuel to the fire for those of my friends that think the whole Modernist thing is just a stupid game for men and that it only is about making food look or feel differently than it should. Yes, ok, so this one is just a bit of fun. Or to produce a new and sensational feeling. Or even a laugh. So what? Why should we not allow food to be fun and playful as well? That is what I like most about Mr. Blumenthal. His playfulness. In addition to trying to make "ordinary" food taste, look and feel better, he also has fun with food. Great!

And now to the tea. The secret behind this piece of food magic is that in stead of being a liquid, the tea is what is called a liquid gel. Or actually two liquid gels, one hot and one cold. A liquid gel is really a more or less thick liquid, normally it is as thick as a sauce or a pure. It is generally made by adding a gelling agent to a liquid, let it set and then destroying the gel by mixing it with an immersion blender or by pushing it through a fine sieve. In this case, however, the liquid gels are very weak so that they can pass as liquids, but still so thick that they will not mix in the cup.

The preparation starts with making the tea. I used half of the recipe in the Big Fat Duck Cookbook page 283. I really do not know how copyrights work in these cases. Can I copy a recipe from a book and publish it in a blog? I would guess not, so I choose not to disclose details here.

Since I did this in the Christmas holidays, I used a Christmas tea instead of the prescribed Earl Grey. The recipe states that the water needs to have between 100 and 400 parts pr million of calcium. I took a chance on my Norwegian tap water, and it seemed to work fine.

The tea is made using cold water and the leaves are soaked for an hour. After the tea is brewed, I divided it in two, one for the hot part and one for the cold part. Now the fun starts. The fluid gel is made with Gellan F. Gellan is a modernist ingredient that is used for making gels. Obviously. It comes in two varieties, Gellan F and Gellan LT100. We want Gellan F here, and I have established that the Gellan variety that my local pusher at Sous Vide Norge sells is just that. The other ingredients needed are

• Sodium citrate - often used to heighten the pH value of a liquid, but here it is used to help the Gellan "hydrate without the impediments of ions" as it is stated in the forum on chefsteps.com. I am unsure how this works, but it looks like Gellan cannot hydrate properly with calcium ions present, and sodium citrate takes care of that. I will look into this when I research Gellan and other gelling agents in a later post.
• Calcium chloride - often used to add more calcium to a liquid, for example when doing spherification. It seems that for Gellan to set, it needs calcium, but since we took care of those ions while hydrating the Gellan, we need to supply new ones for it to be able to set. In other recipes with Gellan, all this is not done, and I do not know why it needs to be done here. It may be because of the rater low concentration of Gellan to make a weak liquid gel.
• Malic acid - this is an acid found in many fruits. It has a mouth watering effect in that it makes your mouth produce more saliva. This is used in an ingenious way here. The tea that we will produce is thicker than normal tea, but the presence of malic acid makes you produce more saliva which will dilute the tea in your mouth making it appear thinner. And since the cold brew will be thicker than the other one, the cold brew gets more acid. Ingenious.

I got these ingredients from Modernist Pantry at http://www.modernistpantry.com/. Buying stuff there and have it sent to Norway worked like a breeze. 

So we have one portion of tea for the cold part and one for the hot part. I added sugar, Gellan and sodium nitrate to both and brought them to a simmer while whisking. This will hydrate the Gellan. Then I made the calcium chloride and malic acid parts for the hot and the cold and added them. This will make the Gellan start to set. At this point I let the two parts rest in the fridge for almost 48 hours. 

When I got them out, they had both set into gels. At this stage, I pushed both gels through my finest sieve. This loosened up the gels and they became liquid like, but the cold one was quite much less liquid than the hot one. My sieve is not the finest there is. It may be that I should have used a finer one. 

Anyhow, I put both semi-liquids in suitable plastic bottles. Before use, I put the hot one in my sous vide water bath and the cold one was taken out of the fridge where it had been for some time and put into ice water. 

Now for the problem of a cup and divider. I have a glass with double sides so that when holding it, you will not feel the difference in temperature and have the surprise spoiled. Chris Young who worked with Heston on the tea project and now works at chefsteps.com (which I highly recommend, lots of classes, recipes and info) has revealed that they were using cardboard that were cut to fit in the cups and then covered with many layers of cling film, making them bot water resistant and more tight fitting. I poured the hot and cold parts into the glass and carefully took out the divider. The two parts stayed separated, oh joy! 

Success. The only negative thing was that the cold side felt considerably thicker than the hot side. I do not know why. I think it was supposed to be a bit thicker than the hot one, but the difference seemed to large and gave the thing away a bit. Even though the cold part had more malic acid, it did not manage to produce enough saliva to dilute it. I did this on January 1st, and we had quite much wine the night before. It could be that I was just too dry in the mouth after that... But all in all, the effect was good. 

A food magic trick, just for the fun of it.