Microbial Terroir

Last week was Beer Week in Philadelphia and was therefore a week of many fermentation-related events for me! On Sunday I was part of a panel of fermentation artisans who spoke about the beauty and bouty of the wild, microscopic beasts that make our fermented foods so very tasty. Obviously I’m not an artisan, but my favorite Philly fermentery, Food & Ferments, is so they provided the goods and I provided the words to accompany them in the vegetable fermentation category.

The question at hand was one of Microbial Terroir.  If you’re a fan of food microbiology, you’re probably aware of Rachel Dutton’s lab at Harvard where she and others, notably Ben Wolfe, do incredibly interesting work surrounding the microbial life in and on food. They write a lot about this question of “microbial terroir.” The simplified idea is that microbial life can be wildly different in different climates, even if those climates are very near to each other (think of your skin and your gut, for instance) and that the microbes in a given area have the potential to greatly impact the taste of fermented foods. So for instance, Philadelphia might have its own particular flavor, and when we use wild yeasts and bacteria to cultivate our food, we’ll have a uniquely Philly product because of that terroir.  In the Dutton lab they’ve studied the microbes responsible for making certain foods very distinctive, with a focus on cheese.  I highly recommend reading as many of their articles as you can.  They make it their business to be readable and accessible to everyone, not just the scientific community, and it’s difficult to read anything they’ve written without saying, “Wow!” a lot. For my husband’s benefit I may start wearing a sign that says, “CURRENTLY READING BEN WOLFE. ANY GASPS SHOULD BE IGNORED.”

A plate full o' Food & Ferments

A plate full o’ Food & Ferments

At the Beer Week Microbial Terroir event I participated in, Nick Bokulich, a microbiologist at New York University’s Langone Medical Center moderated an impressive number of sessions from a group of very talented producers who all use some natural yeast or bacteria (e.g., not pre-harvested or grown in a lab somewhere) in their production. The event highlighted Philadelphia’s artisan fermented food and beverage producers and asked the question: is there something special in our microbes here? 

Wild brews for tasting

Wild brews for tasting

Here are the folks who presented, each with his own answer to that question:

Gerald Olson – Owner/ Brewer at Forest & Main Brewing
Mike Fava – Brewer at Oxbow Brewing
Kirk Schillinger – Sour/Saison Homebrewer
Alex Bois – Head Baker at Fork / High St. on Market
Ezekial “Zeke” Furguson – Manager of Valley Shepherd Creamery
Amanda Feifer O’Brien – Y’all know me
Charcuterie maker  – Chef Andrew Wood of Russet

The room was packed, the talks were interesting, the drinks and food samples were copious and packed with the flavors of wild (but decidedly not lazy) fermentation. The answers to the question at hand were, shockingly, not conclusive. This may be a question for microbiologists to answer, but personally I found hearing it from the producers who depend on these microbes for their livelihoods very compelling!

Philly Homebrew Outlet is selling sourdough starter these days. They brought some to share.

Philly Homebrew Outlet is selling sourdough starter these days. They brought some to share.

The Brewers seemed the most drawn to the concept that there was extra special stuff that made their sour beers taste right. You can understand why. Wild beers, like the very famous Lambic, tend to be difficult or impossible to reproduce outside of their limited geographical reasons. That could be for a variety of reasons, but most brewers don’t take any chances. Brasserie Cantillion, the renowned Lambic brewery in Belgium, famously kept all of the roof tiles in the building when the roof was replaced in 1985.  They weren’t going to risk throwing the baby out with the bath water, or the wild yeast out with the ceiling tiles, to be more precise.

The baker, aka the best bread baker in the universe, Alexandre Bois, had worked in bakeries that had actually tested the stability of wild microbes in their sourdoughs.  What was discovered (and what is also mentioned in some studies I’ve seen) is that there isn’t generally a whole lot of diversity in the microbes present in global sourdough cultures.

Sourdough English Muffins from Philly Bread on the potluck table!

Sourdough English Muffins from Philly Bread on the potluck table!

Zeke, cheemonger extraordinaire and manager of the Valley Shepherd Creamery at Reading Terminal Market, was even less convinced about the importance of wildness in our cheese.  While there are a very few cheesemakers using wild cultures, most rely on specific cultures to produce specific results. There are a few rare examples of wild cheeses, even some local versions from Bobolink Dairy, but the many, many cheese cultures in the world tend to do specific things in cheese and most cheesemakers like to go for a particular end product over the mystery of what will come of wild versions.

Krauts at the potluck table.

Krauts at the potluck table.

I, as mentioned, talked veggies.  Food and Ferments’ beet kvass and assorted pickles were wonderful examples of the goodness that happens with wild bacterial fermentation of vegetables. Since I’m not a commercial producer, I don’t have as much to worry about. My stuff is wild and crazy and if a batch doesn’t turn out as desired, I can start over without too much of a loss. For fermenty businesses, this is a more interesting dilemma. I personally love to believe that there is something special about the terroir of my South Philadelphia row home.  That maybe it began with the Italian family who made their own wine in the basement 100 years ago and continues with me today.

What do you think? Are your microbes special? Does your kraut taste like no other? Does your sourdough rise more perfectly than it would at your neighbor’s house?


  1. Kelly says

    You know, my grandma was commenting on my sourdough recently. She’s of course been maintaining a sourdough starter for decades, and mine is only about a year old, but there’s definitely something good going on in mine. I’ve lived in this apartment for four years, but the woman who lived here before me was here for a very long time. Maybe she was a bread baker too?

  2. Allie Caulfield says

    Where are all of Wolfe’s and Dutton Lab’s papers for reading? I’ve looked at their sites, but I can’t seem to find any sort of repository of literature from them.

    • Amanda says

      Yeah, academic papers of all types can be very difficult to access, a pretty scandalous fact, IMO. Google Scholar is one place to find some good stuff. I also read extracts if I know what I’m looking for. Rachel Dutton and Ben Wolfe are so popular right now, though, that their work is often featured in mainstream magazines and often freely available online. Ben Wolfe in particular writes a lot for laypeople. So it’s definitely worth checking out their links or just googling them to find what’s freely available.

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