Culture is Science

Well, on my way home on the bus just now I was the one responsible for the strange smell. Guilty as charged.

Let me explain.

This morning, a colleague, one of our teaching lab managers Joe, came by with a surprise gift. It was in a black bag, which I opened. Inside was a transparent bag with a quantity of mysterious looking goop in it. From it came the strong and very familiar smell of yeast. Along with it was a piece of paper with instructions.

yeast_cultureYes, it was/is a living yeast culture that Joe wanted to share with some friends. It was this that was with me in my bag on the bus just now. The idea is that you let it grow over ten days or so, and then you either make it all into a batch of bread, or you leave some over to make new cultures that you hand on to others after ten days and/or bake another batch of bread. What a remarkably unusual (these days) gift! (Thanks Joe!)

I’d actually been planning to start up my bread-making again (I used to do it a lot as a student, postdoc, and young professor-with-more-time-on-his-hands), and had intended to blog a bit about it, and so this has come along at an interesting time. Joe actually thought of giving some to me since he noticed from the blog that I am often engaged in cooking one thing or another. So… I’m going to follow the instructions for this “Amish Friendship Bread” and see what happens. I will report. I expect I’ll have two batches of yeast to give away in ten days, so get in touch fast if you want me to hook you up (as all the clever young things are wont to say).

The blog post title? Well, as you know from reading here, I’m a big promoter of the idea that “Science is Culture” in my efforts to put more science (and scientists) “out there” in the public domain. (The excellent SEED magazine have also adopted that as their motto, and they go about the whole business rather well.) This is a play on that. This is a yeast culture we’re talking about, used in the preparation of lots of familiar food and drink. But it is a living organism (or collection) that, through its consuming of the flour and sugar that it is fed, produces, through fermentation, lots of carbon dioxide (among other things) in the form of handy bubbles that make the bread dough rise. Understanding that this is what is going on can make a lot of difference to the quality of your bread-making. You can speed up and slow down the process of rising by changing the temperature of the yeasty dough’s surroundings. You can kill the yeast or severely deplete it by not looking after it very well (not feeding it, or giving the wrong food…).

So this is some of what it said on the paper that Joe printed out to go with the bag (well, close to it… I cut and paste from a slightly different version on the web to save typing):

Day1 This day you receive the batter. Do nothing.
Day 2 Mush Bag
Day 3 Mush Bag
Day 4 Mush Bag
Day 5 Mush Bag
Day 6 Add one cup Flour, one cup Sugar, one cup Milk
Day 7 Mush Bag
Day 8 Mush Bag
Day 9 Mush Bag
Day 10 Mix in large bowl with one cup flour, one cup sugar, and one cup milk. Stir and pour 4 one-cup starters in large zip-loc bags. Keep one starter for yourself and give three other to friends with these instructions.

Hmmm…. you have questions: Wait, isn’t fermentation the same process that is going on in making tasty alcoholic beverages, the main product of interest there being ethanol? Yes. So how come I don’t get all drunk from my bread? Well, the main reason is that you bake off the enthanol, so it is all gone by time it comes out of the oven. I’m guessing that a secondary answer is that there is not an awful lot of alcohol in the dough, given the relatively small quantity of yeast used for a batch of bread. My guess is based on the observation that I was not in a drunken stupor every weekend when I was a small boy after customarily munching on a bit of dough from the batch my mum was preparing for the oven when I was growing up. (Well, as far as I recall… but – maybe my not recalling is a sign! Hmm…).

So now you see the point of the playful title. A little bit of science about the culture, you see.

-cvj

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