March 24, 2013

## Wild yeast sourdough starter

As a logical next step in my fiddlings with bread-making, I just baked my first sourdough loaf with home-made wild yeast starter the other day. To eliminate all suspense, it came out great – by which I mean, it reminded me of all the things I like about sourdough bread without introducing any new negative associations. I especially like it because I did it ‘all wrong’, which is what this post will now document.

“Softly now, softly now – try it, you won’t die.” Silkworm, “A Cockfight of Feelings

So, how I went about this is I got on the ol’ internet and googled ‘sourdough starter’. A little reading got me pretty quickly to the further qualification, ‘wild yeast’ – thus distinguishing the truly artisanal starter from the kinds someone else made that you can buy for a whole lot of money from specialty baking stores, if you’re a clueless snob, or Amazon, if you’re even more clueless but at least not a snob. So once I had the correct verbiage for cheap-ass diy starter, I did some more searching and read through some instructions. (I omit the links because I just told you how to diy, get it?)

Well, opinions about exactly what’s happening with sourdough starter seem to vary a bit, starting with where the wild yeasts are actually coming from. Is it the air around us? Is it the flour? Is it the whole grains you must treat with excruciatingly careful reverence to yield Gaia’s bounty of biomagic? With just a slight knowledge of these matters, I decided it was probably all of the above, plus everywhere else, since that’s where yeasts are. So I ignored the instructions that said I had to be careful not to cover the starter vessel with plastic wrap or anything else impermeable. I also ignored the instructions that said I had to hermetically seal the starter vessel, sterilize every instrument that ever came in contact with the starter, wear a hazmat suit, never use stainless steel, always use stainless steel, never use silicon, always use silicon, and so on.

Go Green!

In fact I pretty much ignored every single instruction designed to seal off the wild yeast starter from the environment it had somehow come from. I also ignored all the instructions designed to make my starter a delicate, difficult thing that required constant, meticulous care. I know people whose lives are given a rich sense of meaning by arranging to provide constant, meticulous care to other creatures, but that’s not me and if it was, I’d pick creatures other than yeasts and lactobacilli.

Speaking of lactobacilli, I paid a lot of attention to discussions of the multi-biotic nature of sourdough starter. It’s not the yeasts that are making the sour, it’s the bacteria. But the bacteria don’t make the bread rise, and they also have a tendency to make the ‘spoilt’ version of sour when they get lonely and pig out. So a functional sourdough starter is actually a community of beasties each creating some of the conditions for each others’ happiness, encouraging each others’ strengths and discouraging each others’ excesses, and incidentally each handling part of a fairly complex little biological process that assembles into a tangy leavening. Which of course wasn’t at all what they ‘intended’, but makes an excellent complement to garlicky cream cheese. So anyway, ‘building’ a starter is a process of getting that community together to work out a harmonious relationship under the conditions they enjoy.

“Control is when others’ locked-in interactions generate a flow of collective behavior that just happens to serve one’s interests.” Padgett and Ansell, “Robust Action and the Rise of the Medici, 1400-1434;” see also Padgett and Powell, The Emergence of Organizations and Markets (2012).

Those conditions are: flour and water. We’re talking about fermentation here, after all, which in real life is hard to keep from happening if you’ve got moist sugars around. Which brings up the mold problem, of which there’s plenty in my house, the dominant strain for unmysterious reasons being ‘bleu cheese’. But fortunately, between the acid the bacteria start producing right away, the alcohol the yeasts start producing soon enough, and the natural division of labor among the artistes of organic decomposition, mold is not actually much of a threat if you’re not trying hard to kill the yeast and bacteria somehow.

Mmmmmmm, stinky.

OK, so I read a whole lot about ambient temperature, water temperature, using bottled water, using distilled water and adding minerals back in, using orange juice, using pineapple juice, using white flour, using rye flour, not using white flour, not using rye flour. With just a slight knowledge of these matters, I reflected on the global success under the most extreme conditions of yeasts and lactobacilli, and decided not to sweat any of these factors too much (although, in principle, I wouldn’t have been completely surprised if a chlorine spike in my suburban tap water had set the critters back a bit). I did decide to take some of the chance out of the lactobacilli, mostly because I had an old tub of plain yogurt handy. And no, it was not any particular brand or type of plain yogurt, but it was past its expiration date as it happens.

I also looked at a lot of instructions about getting a kitchen scale, getting one that measures in grams because they’re more precise, calibrating hydration ratios, using a tall, straight-sided vessel with a dedicated lid, sterilizing this vessel and your hands before handling it, scraping down the sides so that, gosh, I don’t know. So anyway, here was my beginning recipe for my wild yeast sourdough starter:

Some flour
Some water
Some plain yogurt.

Roughly the same amount of each, by eyeball, probably a bit less yogurt because I thought of that as a ‘supplement’.

“My friends always say, the right amount’s fine. Lazy people make rules.” Silkworm, “A Cockfight of Feelings”

All of this went in a plastic bowl (with sloped sides because it has sloped sides) I also eat cereal, pasta, and curry from sometimes; with some plastic wrap loosely draped on top to keep it from drying out too fast. This then went on a corner of the kitchen table I wasn’t using for anything else right then. I am woefully ignorant of the exact temperature of this spot, but I can guarantee it was neither hot enough to bake nor cold enough to freeze my arse. I started with bread flour, I think, but I ran out of that before the next feeding so I switched to rye for awhile because I had a bag of that open and it kept getting mentioned in the instructions. Then for awhile what I had open and easy to get at was some white whole wheat flour, so I used that.

And speaking of feeding, I read all kinds of instructions about pouring out exactly [some ratio I forget] of the starter before each feeding, adding back [another exact ratio I forget] of flour and water, doing this once a day at first and then every 12 hours, carefully swabbing down the sides of the container, adding strips of tape to allow precise measurement of the starter’s expansions and contractions, holding the container between your knees and counting to 6,327 by perfect squares, and checking carefully for ‘hooch’, which is such a precise technical term that at least half of the folks using it have no idea it’s why there’s NASCAR.

Medicinal purposes only, of course.

What I did instead was pour some out and add some back, roughly the amount it had expanded in the interim; when I remembered it, which was anything from a couple times a day to every couple of days. I tried to keep it pretty soupy because I read the beasties like to be wet, and I’ve found this to be true. I did this for something between a week and two weeks – I did not keep track. About day 2 or 3 it got that sourdough smell, then it settled into a kind of sweet peachiness I had not expected. I got back onto the internet and found a long forum thread on the many, many different permutations of ‘sweet peachy’ smell ranging all the way to ‘spiced apple’ that can be expected from a properly harmonizing community of yeasts and bacteria. Reassuring. So when I got sick of waiting any longer, although I think I was supposed to, instead of pouring out the extra I poured it into a bowlful of the flour I happened to have handy and open right then. Whole wheat, rye, and kamut as I recall – kamut btw is fun stuff, an heirloom grain that has a lovely buttery flavor and adds amazing elasticity to a dough.

Here was the ‘recipe’: salt in the right amount for the flour, bit of sugar to be friendly, touch of olive oil and enough warm (tap) water to make a wet dough just drier than a batter. Because the beasties like to be wet. Once they’d fermented that up for most of a day, I stretched, folded, smeared, punched and kneaded in enough more flour that it would stay in a loaf shape (not doing this is how you get ciabatta); let it think about that for maybe an hour longer; threw it in a hot oven on the pizza stone; dumped some water in the bottom of the oven to get some steam to keep the crust from setting too quickly (thank you internet); and some time later there was delicious whole wheat / rye / kamut multigrain sourdough bread.

Through all this I was aware that by failing to control for every possible variable the project could go horribly awry rather than pleasantly a rye. I reflected on the \$.50 of flour and aggregate 10 minutes of work that would be irretrievably lost, and decided to roll those dice.

Does this mean none of the variables all that internet fussing is trying tightly to control don’t matter? On the contrary, I’m sure they do. But my little experiment suggests most of them other than flour, water, a container, and temperatures somewhere between freezing and baking are conditions of the ‘inus’ variety:

“The inus condition is an insufficient but non–redundant part of an unnecessary but sufficient condition” [quoting Cartwright, Nature’s Capacities and their Measurement, 1989, citing Mackie, The Cement of the Universe, 1980]. It’s best to read that backwards: you identify causal conditions sufficient to produce a given effect, but know that there are other conditions that could have produced the same effect. Within the sufficient conditions you’ve identified is a condition that couldn’t produce the effect by itself, is separate from all the other conditions that along with it could produce the effect, but must be among them for the effect to be produced through the causal pathway that’s been picked out. The inus scenario (any scenario containing an inus condition) shows up frequently in attempted causal analyses, and has to be accounted for somehow in any comprehensive causal theory (Chuck Dyke aka Dyke the Elder, “Cartwright, Capacities, and Causes: Approaching Complexity in Evolving Economies,” draft-in-progress).

There are lots of ways to skin a cat. Which means there’s an interesting sociology of popular science lurking in the internet’s various treatments of wild yeast sourdough starter. There are many strategies on offer, each presenting a series of essential steps to success. And each of the strategies will in fact result in a successful culture, while adding procedures that may be important only to offset the sabotage added by other procedures, or to create an outcome distinguished only by the specific way it was achieved; or not important at all except for attention focus or ritual (which, by the way, are not trivial considerations). Apparently when a thing happens to work one way, we can be inclined to leap to the conclusion that this is the one best way to make it happen; ignoring all evidence to the contrary, for example all the other ways described in their own loving detail by other practitioners just as convinced of the robust essence of their accidental triumphs.

Incidentally, this is also how I think about education in general, and general education in particular.

January 24, 2011

## Lattice Model of Information Flow

I am caught in a maelstrom of work and so I decide to play.

I have an excellent textbook on discrete mathematics on my shelf  from a course I took as a student a few years ago [1]. Its always useful to review such books to remind oneself of certain foundational principles used in computer science [2]. My thesis work concerns, among other things, the study of information flow and in the course of my work I found myself consulting this book to review the mathematical concept of a lattice [3]. Looking through the index of this text I found an entry reading ‘Information flow, lattice model of, 525’. Naturally, I was intrigued.

Funnily enough, the three paragraph section on the lattice model of information flow is only of tangential relevance to my thesis work; yet it was interesting enough. It discussed the uses of lattices to model security policies of information dissemination. Rosen presented a simple model of a multi-level security policy in which a collection data (the authors use the word information) is assigned an authority level A, and a category C. The security class of a collection of data is modeled as the pair $(A,C)$. Rosen defines a partial order on security classes as follows: $(A_{1},C_{1})\preceq (A_{2},C_{2})$ if and only if $A_{1} \leq A_{2}$ and $S_{1} \subseteq S_{2}$. This is easily illustrated by an example.

Let $A = \{A_{1}, A_{2}\}$ where $A_{1} \leq A_{2}$ and $A_{1}$ is the authority level secret and $A_{2}$ is the authority level top secret. Let $S=\{diplomacy, combat ops \}$ [4][5]. This forms the lattice depicted in figure 1.

Figure 1

The objective of such a security policy is to govern flows of sensitive information. Thus, if we assign individuals security clearances in the same way that information is assigned security classes, then we can set up a policy such that an item of information i assigned a security class $(A_{1},C_{1})$ can only be disseminated to an individual a having security clearance $(A_{2},C_{2})$ if and only if $(A_{1},C_{1})\preceq (A_{2},C_{2})$.

Without looking at the literature [6], it seems that the obvious next step is to embed this into a network model. Supposing that one has a network model in which each node is classified by a security clearance there are a variety of useful and potentially interesting questions that can be asked. For example, one might want to look for connected components where every node in the connected component has a security clearance $(A,C)$ such that $(A,C)\succeq (A_{j},C_{k})$ for some j and k. Or if one were interested in simulating the propagation of information in that social network such that the probability of a node communicating certain security classes of information to another node is a function of the security class of the information and the security clearances of those two nodes.

So far this discussion has limited itself to information flow as dissemination of information vehicles, contrary to the direction I suggested in my last post should be pursued. One easy remedy might be to have minimally cognitive nodes with knowledge bases and primitive inference rules by which new knowledge can be inferred from existing or newly received items of information. This would have several consequences. Relevant items of novel information might disseminate through the network (and global knowledge grows), and items of information not originally disseminated, for example because it is top secret, may yet be guessed or inferred from existing information by nodes with security clearances too low to have received it normally.

Moving away from issues of security policy, we can generalize this to classify nodes in social networks in other systematic ways. In particular, we may be interested in epistemic communities. We might classify beliefs and/or knowledge using formal tools like formal concept analysis, as I believe Camille Roth has been doing (e.g. see his paper Towards concise representation for taxonomies of epistemic communities).

Fun stuff.

[1] Rosen, Kenneth H. Discrete mathematics and its applications. 5th edition. McGraw Hill. 2003.

[2] Some undergraduates joked that if they mastered everything in Rosen’s book, they would pretty much have mastered the foundations of computer science. An exaggeration, but not far off.

[3] A lattice is a partially ordered set (poset) such that for any pair of elements of that set there exists a least upper bound and a greatest lower bound.

[4] According to Wikipedia such the US uses classifications like the following:

1.4(a) military plans, weapons systems, or operations;

1.4(b) foreign government information;

1.4(c ) intelligence activities, sources, or methods, or cryptology;

1.4(d) foreign relations or foreign activities of the United States, including confidential sources;

1.4(e) scientific, technological or economic matters relating to national security; which includes defense against transnational terrorism;

1.4(f)USG programs for safeguarding nuclear materials or facilities;

1.4(g) vulnerabilities or capabilities of systems, installations, infrastructures, projects or plans, or protection services relating to the national security, which includes defense against transnational terrorism; and

1.4(h) weapons of mass destruction.

[5] An interesting category of information is information about who has what security clearance.

[6] Where fun and often good ideas go to die.

December 15, 2010

## Diffusion of Informational Contents

Research into diffusion processes permeates disciplines as diverse as computer science, anthropology, sociology, economics, epidemiology, chemistry, and physics[1]. Much recent work, in the last fifty years or so, has been explicitly network oriented and has sought to better understand how network topology and transmission mechanisms determine properties such as the rate of diffusion and the various thresholds at which diffusion processes become self-sustaining.

Despite the many apparent similarities between different diffusion processes, it is important to be attentive to the particulars of each kind of diffusion process. Commercial products diffuse among consumers in ways different than do news articles or news topics in the blogosphere (see Dynamics of the News Cycle). Behaviors like smoking spread across networks of friends in both similar and contrasting ways as those of sexually transmitted diseases. And routing information in a sensor network propagates differently than routing information in a mobile phone network.

### Diffusion of Semantic Content

The diffusion of information or more generally semantic content has been a cross-disciplinary concern, and has been treated in a variety of ways, depending on the domain of application. It is generally recognized that such content exhibits properties that distinguishes it from the diffusion of other phenomena. For example, it is recognized that the sharing of semantic content, unlike commodities, does not necessarily incur a consequent loss of that content for the sharer, and that information is often shared preferentially with those for whom it may be of interest or desired[2].

Nonetheless, in more general settings the implications of the properties of semantic content for its diffusion has to my knowledge not yet been formally investigated. Content is typically treated as a non-relational item whose diffusion-mechanism is essentially content-neutral, except perhaps in its differential transmissibility or mutability. Furthermore, it frequently restricts its models to the diffusion of isolated pieces of content in an otherwise content-less context. Consequently, it confounds the diffusion of content vehicles with the diffusion of the semantic content itself, treating content vehicles as having an intrinsic meaning or significance.

It is true that the transmission of content vehicles is easier to understand, and that this simple approach probably does a fair job of approximating the diffusion of semantic content at a unit of content or level of abstraction at which the applicability of a more rigorous approach may not be either readily apparent or especially necessary. Yet it has the unfortunate effect of potentially blinding us to the way in which the relation between contents and cognition (or computation) can generate a second, more leaky, means of content diffusion, or can inhibit or transform content. For example, it is entirely possible for  multiple agents in a network to independently infer the same piece of information without that  piece of information ever having been explicitly communicated to them. It is also, I might add, entirely possible for two agents to receive the same communications and infer entirely different things, or fail to interpret the message correctly, as anyone who has had to try to collaborate with others by email can readily attest.

[1] See my recent blog post Processes of Diffusion in Networks

[2] Unlike disease, which neither the giver or receiver desires!