For those of you who aren’t in “the know”, the Third Annual Boston Fermentation Festival is happening this Sunday, October 4 (and it’s free!). Aeronaut will be there pouring beer samples, demonstrating sour beers and fermentation science in the “Science Corner”, and sharing knowledge at the “Fermentation Help Desk”. We are also excited to be hosting the official After Party right in the Aeronaut Tap Room. We’ll be serving our beer, giving fermentation-focused tours, and Tasting Counter will be sharing some fermentation-focused foods, like miso-cured duck with pickled veggies. As we gear up for this exciting Sunday, those of us who make a living out of feeding microbes take some time to reflect on the power and appeal of fermented foods.
Shit where you eat. Please.
As most Fermentation Fest attendees will attest, the best foods are those that have already been partially digested. Farm-fresh plants are appealing to humans and microbes alike. When yeast and bacteria gain access to fresh foods like cucumbers, barley or juice they immediately go to work eating whatever sugars they can get at. If this is set up correctly, what they will create is a soup of their own waste products blended with undigested bits of food. In the case of pickled vegetables, this usually takes the form of a sour, more limp and pungent version of the starting material. With wines and beers, we get a mix of undigested complex sugars and alcohol. In all of these cases, the microbes typically only cease their feeding frenzy when they are either out of food, or when they are literally drowning in their own waste. Acids and alcohols are toxic for these microbes, even at middling concentrations. Fortunately for us, this results in some balanced, highly palatable foods and it’s in large part because the microbes, complex as they are, have still not figured out how to avoid shitting where they eat.
And it’s not just acids and alcohols that infuse these fermented products. In fact, microbes also generate other more sparse chemicals like phenols and sulfur compounds that contribute complex aromas and flavors. Beyond giving these foods sourness or intoxicating qualities, they provide character. Sometimes this takes the form of a bubblegum smell. Other times, it’s like rotting flesh. Achieving the right balance and ratio of these compounds takes knowledge and years of experience. Practitioners of fermentation strive to know how to choose the right starting products in right amounts, and how to keep them under the right conditions for the right amount of time. This is the art of fermentation.
Our place in fermentation history
On the most superficial level, humans have an aversion to the smells of fermentation, at least at first. It’s likely that this has a basis in natural selection, since in uncontrolled settings, fermentation usually accompanies putrefaction and the generation of toxins. Eating spoiled foods is not generally good for you. It’s historically been safer to just avoid things that have certain “off” smells. But over time, as humans are apt to do, we’ve engineered the risk out of this situation. Generations of beer- and cheese-makers have figured out how to let microbes get involved in the process without putting the consumers at risk. We know, for example, that the blue mold on a ripe Roquefort is not only harmless, but adds a delicious spiciness to the cheese. We’ve known for centuries that the vigorous bubbling produced by the yeast cultures transferred from batch to batch of beer, is a sign that alcohol is being produced, which prevents harmful bacteria from growing. Generations of trial and error have given humanity the recipes for fermented products that are tasty and safe.
Viewed from a microbiological standpoint, what we’ve learned is how to empirically set up culture conditions that select for specific microbes. Salty brine is the perfect environment for the exotically named Leuconostoc mesenteroides, which kicks off the pickling process for cabbage and cucumbers. Roquefort’s blue mold, Penicillium roqueforti, needs a bit of oxygen but not too much, in order to grow. So cheese-makers have learned to poke holes in the pressed curd prior to aging. Lactobacilli do well in warm temperatures and then produce acid, which blocks the growth of other microbes. Thus, our yogurt makers keep milk warm to help with the process.
Though humanity owes many of its achievements to trial-and-error, tradition and empiricism, as we mature we demand to know the underlying truth. Over time, we’ve started putting the pieces together and now know the identities of many of the individual microbes involved, as well as the metabolic pathways of the relevant processes. This has had some unintended effects. In the beer world, the works of Pasteur that led to the isolation of individual Saccharomyces colonies resulted in highly reproducible and very “clean” fermentations. This made brewing possible at immense scales. The resultant 20th century dominance of macro-breweries left us (particularly here in the USA) with a rather boring and flavorless understanding of beer. In time, as we grew more worldly and some of us sampled the lambics of Belgium and the Stock Ales of England, we became aware that something was missing. There was a complexity that was seriously lacking in our beers, due to the absence of other microbes, thought of as contaminants during the age of classical microbiology. It has only been in the last decade or two that non-Saccharomyces microbes have made a significant comeback in our beers. The story of cheeses in this country is surprisingly similar.
There’s a common theme here. Industrialization increased the reproducibility and uniformity of our products and our belongings. Importantly, this increased access to these products, but as we’ve grown used to these things and become more sophisticated in matters of aesthetics and flavors, we’ve increasingly yearned for strangeness and heterogeneity. This story is eloquently told in the book “Salt: a world history”, by Mark Kurlansky. He writes of the advent of table salt by Morton’s, which was celebrated for its uniformity and purity. This salt was so uniform that it could be poured. While this product is still on everyone’s dinner table today, there is a growing market for Himalayan pink salt and fluer de sel, which are distinctly different and non-uniform. Today, more and more people demand foods with character–foods that aren’t “clean”.
Something smells rotten
The first time someone put a bowl of kimchi in front of you, I would wager that you were not immediately salivating at the smell. “Garbage” or “barnyard” were not in your then-juvenile lexicon of things epicurean. But for many of you, your curiosity outweighed your reluctance and you tried a bite. At that moment, you were greeted by a strange mix of flavors–sour, spicy, salty…and you reserved judgement. This was too odd to dismiss or accept just yet. Over time, more opportunities presented themselves and you found yourself wanting to try more. Somehow, the odd smell of decay and the accompanying feeling of uncertainty gave the whole experience a depth wholly absent from your daily meals. Those hours spent alone at McDonald’s, wolfing down Big Macs and fries now seemed even emptier. You found yourself craving fermented cabbages. This feeling didn’t end there, though. It spread to items like washed-rind cheeses and sour ales. Fermented foods elevated your eating experience to something almost spiritual.
A mix of disgust and desire now attend you as you devour these foods. Consuming these not-quite spoiled foods is an act of hedonism with curious parallels to the erotic. Indeed, spankings, hair-pulling and the smell of sweat were probably not things you thought you’d ever enjoy when you were young, but here we are. And it’s not just you: there is a growing public consensus that fermented foods are desirable. Now, we are entering a time when our love of fish sauce (which, incidentally, is derived from barrels of pressed dead anchovies) can be declared as boldly as our love of nipple clamps. We’ll see you at the Fermentation Fest.
We’ll be reporting back after the festival for part 2 of this article. Stay tuned…