Tech rundown: The magic of everyday chemicals

Agar agar

Although some of the ingredients used in avant-garde cuisine are hard to find, expensive and have short shelf lives, some of them can be easily found in major grocery stores, health food stores and ethnic markets. Here are a few of the more readily available “everyday chemicals,” where you can get them, and what they can do:

Gelatin

In the modern age of alginate, carageenan and gellan, gelatin remains one of the best gelling agents around. It has a fairly narrow range of uses, but its melting point of around 100F/40C means it literally melts in your mouth, giving it excellent flavour release. It also has a very satisfying texture, as long as you don’t use too much, which can make your gel rubbery. Plus, of course, it has the benefit of being available in nearly every grocery store. (Get it in sheet form if you can, but powdered will do under most circumstances.) One of my favourite tricks with gelatin, picked up from the Alinea cookbook, is to lay down a layer of a flavourful gelatin gel in a pan, chill it until it’s just set, then place some kind of garnish on the gel, and pour the rest of the (still liquid) gelatin base on top, covering it completely or most of the way. Once the whole thing is thoroughly set, you end up with garnish that is completely encased in a flavourful gel.

Citric acid and baking soda

Have you ever mixed baking soda with vinegar? Maybe as a grade-school science experiment involving a volcano? It makes lots of bubbles, right? Well, you can do the same thing in the kitchen. Vinegar has two problems, though: first, it’s a strong flavour. Second, it’s a liquid, which makes it difficult to delay the reaction. Enter citric acid: a relatively flavourless, granular acid. Mix it with a little baking soda, and maybe a pinch of sugar to mitigate the baking soda’s bitterness, and sprinkle it on some food. Once that food hits the moisture in your mouth, voilà! Instant bubbles. It’s a fun trick that mixologist Eben Freeman uses in his “Jellied Gin and Tonic”. Incidentally, it’s also the underlying chemistry of baking powder: a powdered acid and powdered base combine in the presence of water to make carbon dioxide bubbles that make your cake rise.

Agar agar

After gelatin, agar agar (sometimes called simply agar) is the next most common gelling agent around. If you’ve never seen it for sale, the chances are you haven’t spending enough time in your nearest Asian market. Derived from several types of algae, it’s traditionally used in Asian desserts. To my palate, agar has one big drawback: the texture of the resulting gel just isn’t very pleasant. It’s brittle, and agar’s high melting point (185F/85C) means that it doesn’t melt as you chew, so that brittleness never really goes away. Moreover, unlike gelatin, you can’t change the texture of an agar gel by varying the amount of agar you put in it. However, agar does offer two real benefits: first, that high melting point means that you can warm agar gels before serving. Second – and more important – if you make an agar gel, then break it up and blend it thoroughly in a blender, it produces what’s called a “fluid gel.” That is, it’s thicker than the liquid it was made from, but it’s no longer rigid, so it can be put in a squeeze bottle and used as a thick sauce to garnish a plate. My second favourite use of agar is to put it in a squeeze bottle while still warm and liquid, then drip it into a container of cold oil, producing small spheres of gel that make a beautiful garnish or can be served on their own as a “solid” cocktail, for example.

Lecithin

This product, derived from soy and commonly found in health food stores in either liquid or granular form, is an excellent emulsifier; it’s commonly used in salad dressings to keep the oil and vinegar mixed. It can also be blended with a liquid, usually at less than 1% of the total weight, to make bubbles from things that don’t usually make bubbles. Some people object to the appearance of these lecithin-based “airs,” but they can be a very dramatic way to present intensely-flavoured ingredients. (It’s not really a great technique for mild flavours, since the bubbles lessen its impact.) Lecithin’s biggest drawback is that it’s somewhat perishable, so keep it in your fridge and use it promptly.

Xanthan gum

Xanthan gum is a thickener that can be easily found in most health-food stores. (It’s a common ingredient in gluten-free baked goods.) It thickens in very, very small amounts, and the resulting mixture is “thixotropic.” That means it’s thinner when it’s moving than when it’s not (like how ketchup won’t come out of the bottle, then suddenly comes out all at once), which means that it clings well to whatever you put it on. Xanthan gum dissolves very easily in cold liquids, which lets you thicken delicately flavoured liquids that might be damaged by heating. Xanthan’s biggest problem is that, if you use too much of it, it can become… snotty. Not a nice texture, so use a light hand.

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3 Responses to “Tech rundown: The magic of everyday chemicals”

  1. Nicely stated. You could even do a part II to help people understand where all this trans-fat stuff is heading. I have experienced a minor miracle from using n-kinase (soy lecithin) to cure my corpal tunnel. The key to using it is to complement it with a good fish oil, like krell oil. Also, I use Omega 3-6-9, yet I just heard we don’t need to supplement our 6’s and 9’s.

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