Daily Archives: December 22, 2013

Salt and bread making


Salt is one of the four essential ingredients in making bread, along with flour, yeast and water. Nothing more is needed, although often a lot more is added.

Salt is listed in all the recipes. Only one bread I’ve ever read about is salt-free (a Tuscan specialty mentioned in William Alexander’s book, 52 Loaves).

We tend to assume salt is simply for flavour, but it is also part of our basic biology:

I find it easiest to think of salt as one half of the body’s water-regulation system, the other half being potassium. The membranes of every cell in the body allow water to flow through in direct proportion to how much sodium and potassium are present in the immediate area. Too much or too little sodium in the body affects everything from digestion to blood pressure to brain function.

Since proper sodium levels are so important, the body uses the kidneys to maintain a precise balance. The system is very efficient, which means that if you eat more sodium than the recommended daily allowance, you’ll simply excrete whatever you don’t need (within reason). That also means that we tend to crave more salt than we actually need to eat, which might explain its flavor-enhancing properties.

Salt, as the site above tells us, suppresses bitter flavours, which means some foods taste better salted (at least in my cultural background, which favours sweet and salty over sour and bitter). Because it suppresses bitter, which in turn suppresses  sweet and sour flavours, these flavours come across as stronger in the presence of salt.

Which suggests that a bread with a sweet factor – say raisins, coconut or cranberries – can have a higher salt content than a plain bread, because the salt will enhance the sweetness. So less sugar, more salt? (Okay, I don’t cook with processed sugar because I try to avoid it in my diet…)

Read this food science piece in Nature about salt, food and flavour. Very interesting.

Taste and flavour are not quite synonymous, as the National Institute of Health reminds us:

Taste and flavor are terms that are often confused. The word “taste” has two meanings, one technical and the other as commonly used in the English language, which encompasses the larger concept of flavor…

The sense of taste, one of the five major senses, is defined based on anatomy. In mammals, it is the sense subserved by taste receptor cells located primarily on taste buds in the oral cavity. These taste receptor cells are innervated by branches of the seventh, ninth, and tenth cranial nerves that synapse first in the brainstem prior to sending messages to other parts of the brain…

Virtually all foods and beverages impart sensations in addition to taste. For example, a complex food such as soup not only has taste properties (e.g., it is salty, sour, or sweet) but also has volatile compounds that give it its specific identity (e.g., pea soup compared to potato soup), and it may also have burning properties, such as those caused by hot peppers… In common parlance, the entire sensation elicited by this food is called its “taste.” However, most scientists would instead use the term “flavor” to refer to this total sensation, and that is how it will be used here. It should be noted that many also include the texture of a food as a component of flavor. Taste molecules such as salt can influence flavor in many ways, some of which are described below.

Of course, salt plays other roles in the baking, fermenting and gluten development stages. According to the Wild Yeast blog:

  • Salt affects dough texture, making it stronger and less sticky, as the commenter noticed.
  • Salt reduces oxidation of the dough during mixing. Oxidation causes the degradation of carotenoid pigments in the flour that contribute to flavor and crumb color.
  • Salt regulates yeast activity, causing fermentation to progress at a more consistent rate.
  • Salt affects shelf life. Because it attracts water, it can help keep bread from staling too quickly in a dry environment. However, in a humid environment, it can make the crust soggier.

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How hot is your oven?


Oven thermometerSeems like a silly question: the answer would be it’s as hot as I set it to be. Isn’t it? Well, no, it may actually be rather different from what you expect, based on my recent tests.

I was reading on several bread-baking forums about oven temperatures and the effects on baking. Specifically on the crust: higher temperatures (450F and up) lead to crunchy crusts as the sugars caramelize rapidly. Then there’s “non-enzymatic browning:” the Maillard reaction that happens at a range of temperatures:

The reactive carbonyl group of the sugar reacts with the nucleophilic amino group of the amino acid, and forms a complex mixture of poorly characterized molecules responsible for a range of odors and flavors… In the process, hundreds of different flavor compounds are created. These compounds, in turn, break down to form yet more new flavor compounds, and so on. Each type of food has a very distinctive set of flavor compounds that are formed during the Maillard reaction. It is these same compounds flavor scientists have used over the years to make reaction flavors.

The Maillard reaction is what makes bread become toast. Caramelization is different, as Wikipedia also tells us:

Caramelization is an entirely different process from Maillard browning, though the results of the two processes are sometimes similar to the naked eye (and tastebuds). Caramelization may sometimes cause browning in the same foods in which the Maillard reaction occurs, but the two processes are distinct. They both are promoted by heating, but the Maillard reaction involves amino acids… whereas caramelization is simply the pyrolysis of certain sugars.

The following things are a result of the Maillard browning reaction:
Caramel made from milk and sugar, especially in candies: Milk is high in protein (amino acids), and browning of food involving this complex ingredient would most likely include Maillard reactions.
Chocolate and maple syrup
Lightly roasted peanuts

When cooking, the Maillard reaction can be achieved at lower temperatures (for example, when using the sous-vide method or when searing meats) by increasing the pH of the item being cooked. The most common method for accomplishing this is by using baking soda as a catalyst to facilitate the reaction.

Some complex chemistry going on there (which is one of the reasons bread making intrigues me: it’s science in the kitchen!).

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