It was a night of culture – yoghurt cultures. Vaughn Tan shared his passion for yoghurt with about two dozen captivated future yoghurt makers. He spoke about the biochemistry and microbial ecology of the process – ways to optimize the proteins in the milk, effects of inoculation temperatures, the activities of the different bacterial populations in the culture.
Complex systems
The coolest thing Vaughn explained was about the three key populations of bacteria in yoghurt, their optimum growth temperatures, and how he varied inoculation temperatures to encourage the right populations of bacteria to grow. He pointed out that the usual yoghurt recipes keep the yoghurt culture at a single temperature; this likely diminishes the cultural diversity, reducing the quality of the yoghurt. It was clear that Vaughn’s delicious yoghurt benefitted from a multi-organismal systems understanding.
Ancient cultures
Of course, he brought samples (tasty!) and encouraged everyone to take a bit home. The story around this strain was that Vaughn got it from the Google yoghurt three years ago, and the Google cook apparently got the strain from India, where it was already 500 years old, so we joked that the strain was 503 years old.
But Vaughn mentioned that these complex cultures are always changing, so they really are not the same culture when folks take samples to new places. Also, most cultures come from a previous one unless someone starts one from nature, so it’s highly likely this culture might be even older than we think.
Vaughn was also encouraging us to take some home as an insurance that this strain never dies out. That made me feel that I’ve become part of Vaughn’s network of apprentices, carrying the “flame” of this strain.
Here’s the culturing guide for download.
The cultured crowd
Vaughn led a great discussion, and the audience was quite engaged. Mac posed a great question regarding the copyright of strains, if there were legal ramifications to using strains taken from commercial yoghurts, such as from Vaughn’s favorites Stonyfield and Seven Sins (I think that’s what it was called). I joked that commercial strains could be fingerprinted for copyright protection.
In the spirit of Folk Microbiology, Keegan brought his microbial battery. It also uses a heterogeneous bacterial culture of aerobic and anaerobic bacteria to create a useful electric gradient.
Also, I brought a few bottles of my own home-brew (an IPA) for everyone to enjoy. Alas, my brew was started with commercial yeast, most likely mono-cultural, though, no doubt, itself an old strain. Vaughn urged me to experiment with lambic-style open-air inoculation of my beer, with the potential benefits of a heterogeneous culture. Heh. Could be interesting. And since sometimes I inoculate with a bottle from the previous batch, I could then start my own strain of beer yeast to hand down to future generations of home brewers.
Awesome experience
As an aside: I brought my 15 year old son along. My highlight of the evening was watching his wonder as he met with everyone, saw their demos, read some books off the shelves, and, basically, saw that there are many ways to express one’s curiosity and creativity. From dirt batteries, to electronic poi, to ancient bacterial cultures, his expanding world was pure joy for me.
