Adventures in fermentation

Fermented foods have taken the food world by storm recently. It really isn’t any surprise. The process is pretty easy to do at home, requiring nothing more than some salt and a Mason jar. The microbes in them are believed to be beneficial for health, and there is increasing scientific evidence to back this up. The process hearkens back to a simpler time. Often, the flavors are more interesting and complex than alternative methods. Like anything that requires a Mason jar and allows people to feel knowledgeable, superior, and healthier than the main stream of American society, it has taken off.

I have been jumping on and off of this bandwagon for years (in some cases, even before it was cool). A couple of months ago, I decided that I would like to try making my own kombucha at home. I could have ordered the necessary culture from an online company, but I know that cultures grow and people are always looking for new homes for the babies. I sent an email to the listserv maintained by our neighborhood organization, asking if somebody had one they could split and share with me. I received a positive response and have been happily brewing kombucha in my kitchen ever since. I also got an email from the woman who runs the neighborhood newsletter, asking if I would write an article about fermented foods. I wrote what I felt was the bare bones of an introduction to the subject. She told me it was so long it would take up two whole pages, possibly bumping the article about kombucha written by my benefactor. We edited it some and I hope she is able to run both pieces. Below is the full version…my idea of a bare bones introduction to fermented foods.

Humans have been manipulating yeast and bacteria to preserve our food, increase its digestibility, and improve flavor for millennia. Some even argue that the chance fermentation of leftover gruel, resulting in rudimentary beer or bread, depending on whether you are talking to a brewer or a baker, was responsible for our ancestors’ choice to settle down into agrarian settlements. More recently, researchers have begun exploring how our intestinal flora can affect everything from our mood to our weight. When Martha Steward is blogging about gut health, it is no longer the province of the radical fringe (http://www.cnn.com/2014/06/18/health/good-gut-bacteria/). Prior to our modern, post-Pasteurian obsession with sterility, human diets contained a lot of bacteria and fungi. Increasingly, we are learning that we may be harming ourselves with our Lysol cleansers and hand sanitizers. Very few people would argue that we should return to a pre-sanitation way of life, but fermented foods are a delicious way to increase the beneficial microbes in our diets.

Whatever you are fermenting, the process is basically the same. The microbes (usually some suite of yeast and bacteria) break down complex molecules into simpler ones. They take starches and break them into sugars, complex sugars into simple sugars, simple sugars into organic acids and alcohols. If there is protein present in any quantity (like when you are fermenting milk, soybeans, or meat), they break proteins into amino acids. These simpler compounds tend to have flavors that are more complex and more pleasant to human taste buds.

In talking about fermentation, of course, we are talking about a process that, when uncontrolled, goes by the less pleasing name, “rot.” The process of fermenting food is about managing the environment to help the “good” microbes thrive and eliminating (or at least out-competing) the “bad” microbes. This is often accomplished by inoculating your culture with a “mother” of the good microbes, giving them a head start on the rest. It can also be done by salting, which creates an environment in which friendly microbes thrive.

Kombucha, which started the process that led to my writing this, is just one of the many non-alcoholic fermented drinks around the world. Kombucha starts with sweet tea, black tea with sugar. A SCOBY (Symbiotic Community of Bacteria and Yeast), or mother, is added and the microbes do what they do. The tea supplies nutrients to the microbes as well as flavor and caffeine to the final result. Like many humans, these particular microbes seem unable to function without caffeine (apparently coffee can also be used, but herbal teas don’t work). Flavorings can be added later after fermentation, though I find the flavors contributed by the microbes to be quite nice all on their own. The SCOBY starts as a pellicle, or thin film of microbes on the surface of the liquid (feared by beer brewers as a sign of infection). This pellicle thickens with each successive batch, forming quite a strong layer. It gets thicker with each successive batch, and can be split to share with others or start a new batch. Water kefir is another popular option, the culture for which looks like those water absorbing polyacrylamide crystals you see in diapers and potting soil. Most people don’t enjoy the flavor on its own and add other flavoring. We did this for several months and gave up after the second time a grape flavored batch showered the kitchen. I much prefer the natural flavor of kombucha, but that is purely a matter of personal preference. A shrub, or “drinking vinegar” is a vinegar (see below) mixed with sweetening and flavorings to produce a beverage or mixer for cocktails.

Of course, the fermented beverages that contain alcohol are even more popular. Beer, wine, mead, and all of the world’s myriad alcoholic drinks owe their existence to Saccharomyces cerevisiae, the same yeast that rises our bread. When deprived of oxygen, it ferments the sugars (from fruit juice, malted grain, honey…or really anything at all) to alcohol. Different strains of this yeast behave differently, producing the distinctive flavors of Belgian beer, Champagne-style sparkling white wine, or any of a number of other regional delights. It is important to note that alcohol has a lot of energy left in it (which is why it burns when concentrated and contains more calories per gram than fats). If oxygen is reintroduced, microbes will use that energy to grow and convert the alcohol to organic acids, which results in wine or malt vinegar.

Of course, sometimes acetic acid is exactly what you want your microbes to produce. Vinegar is a prime example, which you can make by adding a “mother” culture to nearly any sweet liquid and allowing it to ferment out. Most pickle recipes you can find today start with distilled vinegar, which is dead vinegar. There are no good microbes in most of the vinegar you find in the store. Nearly every culture in the world, however, has a recipe for naturally fermented pickles. Sauerkraut, kimchi, and kosher dills are all examples. In these cases, vegetables are salted or added to a salt solution (called a brine) with flavorings and allowed to ferment. 

I have made kimchi several times . In one memorable instance, the matriarch of the Korean family that owned the produce market where I bought my ingredients recognized recognized the combination and inquired. I brought her a sample of the finished product and received her stamp of approval. My recent attempts at lacto-fermented pickles, using both cucumbers and green beans, have been pretty successful. Recipes recommend adding a source of tannins to keep the veggies crunchy. I had no ready source of grape or oak leaves, so I used black tea. It worked and the flavor is great, but the dark staining from the tea is a little off-putting. In the past year, I have also started making fermented hot sauce, in the style of Sriracha. The short fermentaiton period at the beginning adds a depth of flavor that is not available from just adding filtered vinegar. In my opinion, some of it is lost when you heat it to cook it down and thicken it. I am still refining the technique. I've posted links at the bottom of the page to some reliable sources for recipes in case you want to try it yourself. 

My first love when it comes to fermented foods is homemade bread. In today’s post-Atkins, gluten-intolerant world, eating bread is almost a defiant act. But there is evidence that the long, slow ferment of sourdough bread leads not only to better flavor, but a healthier product as well. For some people with gluten sensitivities, it may even solve the problem without resorting to the gluten-free aisle (http://www.theguardian.com/lifeandstyle/2014/aug/12/rise-sourdough-bread-slow-fermented-health-benefits). Sourdough bread is not easy. It is painstaking and slow, requiring weeks of nurturing and then several days to prepare. Done right, however, the slow-rising wild yeast give the bacteria time to break down the flavorless starch in the flour into sugars, organic acids, and alcohols, which make for a better tasting as well as healthier loaf of bread.

Milk has been an important source of protein in many cultures throughout history and there are a number different ways to ferment it. Yogurt, buttermilk, and sour cream are created by adding a bit of the last batch to new milk and maintaining the correct temperature. My forays into yogurt making have never worked the way I would like, with much runnier results than I wanted. The temperature range for these bacteria is often very small, making them more complicated to manage. There are plenty of commercially available yogurts with active cultures and I generally just buy them. Milk kefir is another fermented beverage, much like buttermilk. The mother culture, like water kefir, looks like grains which are strained from each batch. It can be flavored and sweetened to more closely resemble commercial examples.

Then, of course, there is cheese, which has been called “milk’s leap toward immortality.” This is literally true, since cheese is far less perishable than milk. Figuratively, of course, the flavor of aged cheese is much more complex than that of the best milk. Again, bacteria and fungi break down complex molecules (which taste bland to our tongues) into simpler sugars, organic acids, and amino acids. A variety of other microbes can be added or simply introduced from the environment to create a variety of flavors. Washes with wine or salty water, storage in wax or cloth, and aging while controlling humidity and temperature encourage different microbes and produce different results. While I have not yet tried to make cheese, a cheese cave in the basement is something I hope to build soon. I have read that it can be as simple as a plastic box in a cool location to manage temperature and humidity. Hopefully I will be able to write about it soon…

Beer, wine, mead, and all of the world’s myriad alcoholic drinks owe their existence to Saccharomyces cerevisiae, the same yeast that rises our bread. When deprived of oxygen, it ferments the sugars (from fruit juice, malted grain, honey…or really anything at all) to alcohol. Different strains of this yeast behave differently, producing the distinctive flavors of Belgian beer, Champagne-style sparkling white wine, or any of a number of other regional delights. It is important to note that alcohol has a lot of energy left in it (which is why it burns when concentrated and contains more calories per gram than fats). If oxygen is reintroduced, the yeast will use that energy to grow and convert the alcohol to organic acids, which results in wine or malt vinegar.

Of course, sometimes acetic acid is exactly what you want your microbes to produce. Vinegar is a prime example, which you can make by adding a “mother” culture to nearly any sweet liquid and allowing it to ferment out. Most pickle recipes you can find today start with distilled vinegar, which is dead vinegar. There are no good microbes in most of the vinegar you find in the store. Nearly every culture in the world, however, has a recipe for naturally fermented pickles. Sauerkraut, kimchi, and kosher dills are all examples. In these cases, vegetables are salted or added to a salt solution (called a brine) with flavorings and allowed to ferment. See below for recipes.

Meat can also be fermented. Many cultures have fermented fish dishes. Cured meats are flavored by the production of lactic acid by microbes. Meat, like milk, has a lot of protein. This results in the production of amino acids when fermented. One of these, glutamic acid (when purified for use as a food additive, it is known as monosodium glutamate*) produces the flavor known as umami. This accounts for the popularity of fish sauce, its vegetarian alternative developed by Japanese Buddhists, soy sauce, and dry cheeses like parmigiana reggiano. Unlike many of the things I have listed above, improperly fermented meats can cause serious illness. I haven’t yet tried my own charcuterie and may continue to leave that to the professionals. I know people who do it and love to eat at their houses.

Since prehistoric times, humans have been manipulating microbial populations to preserve and flavor our food. Louis Pasteur began the process of removing microbes from the equation entirely, which has increased the safety of our food supply. However, it has also limited the flavors available to us and there is increasing evidence that it has made us less healthy. I have focused on the flavor compounds that fermenting microbes create as byproducts of growth, but we shouldn’t forget that they also are growing and multiplying in there. There is increasing evidence that we increase our own health by eating these foods and introducing probiotic organisms into our digestive systems. So often, eating for health means giving up flavor. Not so with fermented foods. They taste good and are good for us. To get started making your own fermented foods, you can check the cookbook section of your local bookstore. There are several excellent books that have been published recently. For a more 21^st century solution, I have included several links below.

Safety note:  It is important to remember that fermentation produces carbon dioxide. If you seal your jars, while fermentation is active, explosions are a real possibility. An airlock, topping the jar with a cloth, or simply leaving the lid somewhat ajar are all solutions to this problem.

For more information:

For a list of examples of fermented foods:  http://www.chowhound.com/food-news/54958/that-coffees-rotten/

http://www.culturesforhealth.com/ is a great source for information on fermented foods as well as products and cultures. They have several recipes, including a good one for kosher dill pickles, which I have used.

For the adventurous, who would like to try kimchi at home, this is a good recipe:  http://www.epicurious.com/recipes/food/views/traditional-napa-cabbage-kimchi-233839. Korean Korner on Veirs Mill Road is a good local source for ingredients.

*A note on monosodium glutamate:  Glutamic acid, or monosodium glutamate, is one of the first things that humans taste. It is present in mother’s milk in high concentrations, which may explain why we find its umami flavor so pleasant. Its bad reputation is largely due to some very questionable science performed in the late sixties and early seventies. The truth is that it naturally occurs in many foods we eat every day such as fish and soy sauce, parmesan cheese, and mother’s milk. There is plenty of information available and I have no interest in what you choose to eat. If you are interested, here is one such source of information:  http://greatist.com/grow/why-msg-has-a-bad-rap