Cooking for Geeks: Real Science, Great Hacks, and Good Food (43 page)

PHOTO USED BY PERMISSION OF MARTIN LERSCH

Martin Lersch blogs about food and molecular gastronomy at
http://blog.khymos.org
,
which includes the excellent collection of recipes, “Texture: A hydrocolloid recipe collection,” which demonstrates many uses of food additives. (We’ll cover food additives and molecular gastronomy in
Chapter 6
.)

I see from your online bio that you have a PhD in organometallic chemistry. How did you get interested in chemistry in cooking?

My whole food interest is in no way related to my studies or my work, apart from chemistry. It was when I was a student at the University of Oslo, almost 10 years ago, that I found
On Food and Cooking
by Harold McGee in the faculty library. It was very interesting.

So I started looking for more information, but at that time there wasn’t really very much out there. At university, they often have students visiting from high schools, so at one point I was given the opportunity to talk about everyday chemistry; I think the title was something like “Everyday Chemistry in the Kitchen.” Then I put up a web page, and when I finished my PhD many years later, the page had grown, so I figured I would continue. I moved everything to
http://khymos.org
and started blogging.

The whole time, it’s only been a hobby. I’ve always liked cooking. Every chemist should actually be a decent cook, because chemists, at least organic chemists, are very used to following recipes. It’s what they do every day at the lab. I often tease my colleagues, especially if they claim that they can’t bring a cake to the office for a meeting, I say, “Well, as a chemist, you should be able to follow a recipe!” As a chemist, I’ve always had, in a way, curiosity. I bring that curiosity back home into the kitchen and wonder, “Why does the recipe tell me to do this or that?” That’s really the case.

How has your science background impacted the way that you think about cooking?

I think about cooking from a chemical perspective. What you do in cooking is actually a lot of chemical and physical changes. Perhaps the most important thing is temperature, because many changes in the kitchen are due to temperature variations. Searing meat and sous vide are also good places to start. With sous vide, people gradually arrive at the whole concept themselves. If you ask them how they would prepare a good steak, many people would say you should take it out of the refrigerator ahead of time, so you temper the meat. While you temper it, why not just put it in the sink — you could use lukewarm water? Then if you take that further, why not actually temper the meat at the desired core temperature? Most people will say that’s a good idea, then I say that’s sous vide. It becomes obvious for people that that’s actually a good idea.

I’m very fascinated by the hydrocolloids. One of the reasons I spent so much time putting the recipes together was that when I bought hydrocolloids, maybe one or two recipes would be included, but I found them not to be very illustrative. Everyone is familiar with gelatin, less so with pectin, but all the rest are largely unfamiliar. People don’t know how they work, how you should disperse them and hydrate them, or their properties. The idea was to collect recipes that illustrate as many of the ways to use them as possible. You can read a couple of the recipes and then can go into the kitchen and do your own stuff. That’s what I hope it will enable people to do.

I think it’s a fantastic recipe collection, having used it myself for exactly the purpose that you describe. Out of curiosity, is there a favorite hydrocolloid of yours?

No, I haven’t even tried them all — I don’t have all of them in my kitchen.

Really?

I think the reason is more lack of time. With a full-time job, children, family... there’s simply not enough time. It’s a lot easier to skip the practical part and concentrate on the theory.

Is there a particular recipe from which you’ve learned the most or found interesting or unexpected in some way?

It’s hard to think of one recipe. When talking about molecular gastronomy, it’s easy to focus too much on the fancy applications like using liquid nitrogen or hydrocolloids. It’s important to emphasize that this is not what molecular gastronomy is about, although many people think that; many people associate molecular gastronomy with foams and alginate.

I always try to include basic things to get down to earth. One thing that comes to mind is bread. It is really fascinating the great variety that you can achieve by using only water, flour, and salt. With the flour and water, you already have the wild yeast present, so you have everything set up for a sourdough. Then it depends on how you prepare your starter, the ratios involved, how you proof your dough, and how you bake it. Of course, this is not something new; bakers know this. But from a scientific viewpoint, it’s very interesting to think about that. The no-knead bread illustrates a lot of chemistry; you’re probably familiar with that?

I am, but go on.

Glutamine and gliadin, the two proteins that make gluten, can combine all by themselves once you have a dough that is wet enough. The typical hydration for no-knead bread would be somewhere in the 75% to 77% range. You bake the bread in a preheated pot, where you simulate a steam oven. Moist air is a much better heat conductor than dry air, and the moisture condenses on the surface of the bread. It enhances the crust formation and helps the gelatinization of the starch. It also prevents the crust from drying out and limiting the rise of the bread, so you get a much better oven spring this way. Once you remove the lid, everything is set for the Maillard reaction as the crust dries out. So there is a lot about both the way you make dough and the way you bake the bread that exemplifies basic chemistry and physics.

Mix everything until the flour is completely moistened. This should take only about 30 seconds. Cover and let rest at room temperature for 20 hours.

ADAPTED BY MARTIN LERSCH FROM JIM LAHEY’S
NEW YORK TIMES
RECIPE

Place a medium-sized cast iron pot in your oven and preheat both to 450°F / 230°C. While the oven is heating, transfer the dough onto a floured surface and fold three or four times. Leave for 15 minutes. Shape rapidly into a boule — a round loaf — and place on a generously floured cloth towel. Proof until doubled in size. Dump into the preheated cast iron pot and bake with the lid on for 30 minutes. Take the lid off and bake until the crust has a dark golden color, about 15 minutes.

Milling flour is a lot easier than you might imagine: snag some wheat berries — which are just hulled wheat kernels, with bran, germ, and endosperm still intact — from your local health food store or co-op, run them through a mill, and you’ve got fresh flour.

Why bother? Well, for one, the taste is fresher; volatile compounds in the wheat won’t have had time to break down. Then there are the health aspects. Most commercial whole wheat flours have to heat-process the germ to prevent it from going rancid, but this heat-processing also affects some of the fats in the flour.

On the downside, freshly milled flour won’t develop gluten as well as aged flour. For a rustic loaf of bread, this is probably fine, but it’s not so good if you’re trying to make whole wheat pasta, in which the gluten helps hold the pasta together. Of course, you can always add in some gluten flour to boost the gluten levels back up.

You have a couple of options for mills. KitchenAid makes a mill attachment for its mixers. If you do spring for a KitchenAid attachment, though, be warned that it can put quite a strain on the mixer. Set it to low speed and run your grain through in two passes, doing a first pass to a coarse grind before doing a fine grind. Alternatively, take a look at K-Tec’s Kitchen Mill, which is in roughly the same price range but is designed specifically for the task.

You can run other grains, such as rice and barley, through a mill as well. Too-moist grains and higher-fat items such as almonds or cocoa nibs are a no-go, though: they’ll gum up the grinder.

P.S. Don’t expect to be able to mill things like cake flour. Cake flour is bleached with chlorine gas to mature it.
Maturing
— the process by which flour is aged — would eventually happen naturally due to oxidation, but chlorine treatment speeds it up. It also modifies the starch in the flour so that it can absorb more water during gelatinization (see
Making gels: Starches
in
Chapter 6
for more on gelatinization of starches) and weakens the proteins in the flour, reducing the amount of gluten that can be formed. Additionally, chlorination lowers the temperature of gelatinization, so batters that include solids — nuts, fruits, chocolate chips — perform better because there’s less time for the solids to sink before the starches are able to gel up around them.

Wheat berries.

First pass: coarse grind.

Second pass: fine grind.