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.