Dutched Chocolate

My sister recently asked me "Why is cocoa processed with alkali in so many chocolate flavored products?"

First what is alkali processing or dutching? A solution of alkali (a base), usually potassium carbonate, is added to the cocoa nib before roasting. It's also possible to dutch cocoa liqueur or powder. Most of the cocoa liqueur used for making cocoa powder is dutched but the majority of liqueur used for making chocolate is not. Alkalising was developed in the 19th century in the Netherlands by Coenraad Johannes van Houten1. He was trying to develop a chocolate powder that dissolved better in milk or water. Whether or not dutched cocoa dissolves better is still disputed but what the process definitely does do is change both the color and flavor of the cocoa.

The trick is to add just the right amount of base not too much because too much base will cause the triglycerides found in the cocoa butter to saponify thus giving it a soapy flavor. To avoid these off putting flavors small amounts of ethanoic or tartaric acid added to neutralize the high pH.

Some cocoa nibs are very acidic and the alkalising greatly helps flavor of the final chocolate product. Another thing that the base does is promote the formation of Miallard products (see another great article about how bases catalyze the Miallard reaction here.) Miallard products are those great flavors that form when proteins and sugar react.

The color change in the cocoa is due to reactions of the tannins in the cocoa. Tannins are polyhydroxyphenols, which means they are aromatic compounds (as apposed to an aroma compound) with several alcohol (-OH) groups. In the figure you can see a common one in cocoa, epicatechin. Depending on how the nib is fermented, dried, and roasted the tannins can join together, oxidize, and react with other chemicals in the cocoa to form color-giving molecules. This makes the cocoa much darker in color. By varying the pH, moisture content, and processing conditions it is possible to make cocoa of many different colors.

So when should you use alkali unprocessed cocoa? Well that depends on your leavening agent. Baking soda needs an acid to make it form CO2 and cause your cake to fluff up nicely. Adding acidic unprocessed cocoa will cause it to rise. Further more, baking soda is a base and if added to the already basic dutched cocoa it can cause the cocoa butter to saponify and give soapy flavors to the dish. But because baking powder is a mixture of an acid and baking soda you want to use dutched cocoa so that it doesn't taste too acidic.

1Casparus van Houten, Coenraad's dad, figured out how to easily remove cocoa butter from the nibs enabling the creation of cocoa powder. The nib contains about 54% cocoa butter by weight and this butter makes it difficult to mix into water or milk to make a drink. By pressing the beans, either with a hydraulic press or with a screw press, about half of the butter is expelled from the bean and the cocoa mass that is left can be ground into cocoa powder. This then allowed others to combine cocoa powder and sugar together and then remixing it with some of the cocoa butter thus forming something very close to the of chocolate of today.


DB Lavash and dips.

During this challenge Marcelle asked me to take a turn kneading the dough. A little while later, she gave me some constructive criticism on how I knead dough. It turns out that while I thought that I was kneading the dough, I was really just folding the dough in half and smashing it flat time and time again. What I was not doing was pulling and stretching the gluten molecules into a nicely aligned mass.

Harold McGee informed me that wheat flour is special in the grain family because it is the only grain whose endosperm proteins will interact strongly enough to form a gluten (most simply, a combination of gliadin and glutenin) that will support a raised bread. It is true that some other grains (like rye) will form gluten, but the formed gluten is weak and can't support the raising of the bread. To form a good bread the dough must be both plastic and elastic. Able to stretch out of shape when pressure is applied (plastic) and able to pull back to its original shape after the stress is removed (elastic). If the dough were just plastic, all of the carbon dioxide produced by those hard-working, fermenting yeasts would just flow to the surface and escape, making something very like bricks or hockey pucks. On the other hand, if the dough were completely elastic, the CO2 would be crammed into a few very pressurized pockets and the bread would come out looking like swiss cheese: a very dense mass with a few pressurized pockets of gas.

Unkneaded gluten is a coiled up protein that you can visualize like a Slinky. Unlike a slinky, the reason gluten stays coiled up is that there are chemical bonds (disulfide bonds) holding the spiral layers together. Kneading stretches the "gluten-Slinky" until those disulfide bonds break. Once stretched the disulfide bonds can reform with other broken disulfide bonds in the new stretched position to keep the gluten all aligned. After reading about kneading gluten doughs I realized that the disulfide breaking and forming is a lot like what is happening during a permanent wave, but this explanation will have to wait for another post. So even with my poor kneading technique the lavash was delicious, the dips were delightful (mostly), and best of all I learned some new chemistry.

I didn't find this project very challenging. My cracker experience is not vast, but I did make whole-wheat saltine/"wheat thin" type crackers once a week for our baby for about 8 months after he started eating solid foods and before I wanted to expose him to long-ingredient-list store-bought crackers. I have made a lot of pita bread--with a variety of outcomes and a ton (almost literally) of pizza dough, so flatbreads are not altogether foreign to me. The recent lavash challenge was fun and easy and made for a nice snack when we had some friends over to play games one evening.

I followed the instructions exactly, but I had a few problems; here they are, in no particular order. Despite using an oven thermometer and switching the lavash from top to bottom rack and front to back partway through baking, one pan was much darker brown than the other. The paler pan also made lavash that were puffed and chewy. I'm sure this has reference mostly to the cheap oven in our rental home, but other bakers I conferred with confirmed my experience. I used sea salt on one pan and poppy seeds on the other, but despite spraying water, 70% of them fell off before they were eaten.

For the toppings, we decided to try to the Tahitian almond spread recipe provided and also made a basic pico de gallo (tomatoes from our garden, onion, serrano chile, cilantro, salt). I also served some olivada (see Moosewood Restaurant Cooks at Home) I had made with green olives a few days before. The olivada is a long-time favorite and the pico disappeared quickly; when all the chunks had been dipped out of the bowl, the juices were very nearly drunk by our friend. The almond spread was a little weird. I love almond butter and eat it almost every day on toast for either breakfast or on an apple for a maternity snack, but putting it with garlic, cilantro, honey, orange juice and pine nuts did nothing to further endear me to a food I already enjoy as it is. I'm really looking forward to next month.