Yeasts and stuff!
Are you ready for a lesson?

What's a biga?

A biga is a fermented mixture of flour and water that was used to maintain a culture of yeast in days of old. There are many recipes and traditions to making bigas but the history goes something like this. In the old days, bread was something that was made almost every day. Since a source of active (let alone pure) yeast was not generally available from the corner store people cultivated yeast cultures on their own. First they had to collect the yeast from the environment and then selectively culture it by the temperature, food sources and general conditions in which they kept it.

To collect the starting culture they'd set a bowl if water and flour batter out in the open. In a kitchen environment it wouldn't be unusual to find yeast(s) floating around and generally viable strain would more often then not take hold in the batter. In less yeast prevalent environments, like on the prairie in a Conestoga wagon, finding a viable yeast culture was less easy. Sometimes the nastiest things would grow in the batter and you'd have to start all over. When you did get a yeast culture to predominate in the batter, you may not get a strain that was particularly active even though it was the right species (Saccharomyces Cervisae) some strains were more "prolific" than others. Women (I don't mean to be sexist but...) would actually trade prized cultures of yeast for their baking when someone had a particularly active strain. Some weaker strains had the tendency to not exclude other bacterial activity, or produced nasty tasty bread. So a good strain of fast rising yeast was a prized commodity.

A little aside: Saccharomyces Cervisae is also the root of the Spanish word for beer, Cervesa.

So moving right along... the yeast would ferment the batter over time, producing an alcohol content that had to be removed before it killed the yeast that produced it and then replaced by fresh four and water to keep the yeast alive. An alcohol rich liquid rose to the top and the yeast/flour culture settled. Continually performing this separation/feeding process helped select out the other organisms and produced a rather pure yeast culture. After pouring off some of the alcohol, (if possible, Conestoga wagons were known to jostle around a bit) and using some of this biga in their dough they inoculated the dough with the yeast and made bread. Although sluggish at first this yeast will pick up speed and make bread rise but is tends to have lower gluten formation and hence is a bit sticky when handling.

So that's how yeast was developed before commercial yeast was prevalent. I don't know what came first though, beer or leavened bread. I'm thinking beer because that's been known about since the early Egyptians. Risen bread may have been an accidental use of beer instead of water for bread making, but I'm speculating. I suppose someone has an academic treatise on this somewhere but I really don't need to go there. I do know that you can try the yeast culture experiment on your own if you like. You may find a good yeast culture or you may just grow a science project. I had a friend who did this a few years back and indeed he did manage to get slow-growing yeast that made bread. But for my purposes I'll use a commercial yeast.

Development of specialized yeasts:
One more thing of interest on yeast... a few years ago I was real keen on making spiced breads, particularly cinnamon raisin, and I found that a lot of spice retards the yeast. So I set out to develop a strain of cinnamon tolerant yeast. Using the same method of fermenting, separating and replenishing the biga I simply added ever-increasing amounts of cinnamon. The cinnamon sensitive yeast died out and the cinnamon tolerant mutations survived. It's natural selection in your kitchen. Evolution in a jug! It's amazing. The different brands of yeast, as well as the fast rising, which I don't recommend, are different because of these selective culturing techniques.
Fast rising yeasts simply develop gas more effectively without some of the other desirable properties. The acids and other by-products of yeast are responsible for the gluten structure and flavor of better breads.

{Very, very aside: I have to mention this now. And this is not medical advice from me, I am just sharing the opinion of many knowledgeable people. This same evolutionary method that produces better yeasts, and other organisms and plants which we appreciate, is at work in our society producing antibiotic resistant pathogenic bacteria. Whether by mis-prescription, mis-administration or use in animal farming, the misuse of antibiotics is the primary reason we now have deadly bugs that pharmaceuticals cannot kill. When a doctor prescribes an antibiotic without sending a sample to a lab to assure that he is prescribing an antibiotic to which the infection is susceptible, he is initiating a potentially dangerous series of events by which some organisms are killed and the survivors are left immune.

This is especially true when you stop taking the antibiotic prematurely because "you feel better" or the wrong drug of course isn't working and the doctor stops the first and starts another. The words "broad spectrum" should also be associated with "last resort" in today's medical practices and should be a warning sign that your doctor isn't too concerned about the future viability of his arsenal. If possible ask for a lab test for "sensitivity" so at least in a days or so you can be assured that you a) have a bacterial infection and should be taking any antibiotic and b) are taking one that will be effective against what you are infected with.

Some bad mistakes to avoid:
You should never stop an antibiotic prematurely because you feel better (unless of course it's causing another health problem). This is really bad, because you haven't given the drug the required time to annihilate it's target, leaving a stronger deadlier one roaming your system to later do you, or someone else, in.
Or when someone insists they get a prescription for a viral infection. NO ANTIBIOTICS WORK AGAINST VIRUSES! Doctor's frequently prescribe antibiotics to patients because the patient gets angry if they don't "Give them something" even though nothing they give them will have any effect. This is somewhat less prevalent today thankfully.
And the worst... people who self-administer some drug or another, short term, from the last time they didn't finish the prescription. Folks, don't be party to these stupid things. If it doesn't kill you someday it may kill someone else.
Food industry use of antibiotics, what can I say. Be aware of it and let your voice be heard if you can.
By the way, if I sound particularly petulant on this point I should confess, I did acquire a B.S. in Microbiology once upon a time and am very close to very good clinical microbiologist who works in a major metropolitan hospital. We've seen plenty of this first hand, much more than you'll ever see on 60 Minutes or some other 20 minute documentary. Antimicrobial agents, like so many things in our technical age are wonderful things but they are not panaceas to be used without adherence to strict rules for they can be the basis for deadly things to come. Where do you think E. Coli 0157 came from?}

Ok, sorry, I'm off my soapbox, let's go make some biga and do some baking.

To start off you'll need a clean piece of crockery, plastic of other non-metallic container that has a non-sealing lid. If you use sealed plastic-ware it will blow up and I will laugh. You've been warned. It should have 2 - 3 quarts capacity. Also, you should have a non-metallic whisk. The best I've found for this are the plastic covered whisks that are readily available in any kitchen store.

Dissolve together:
2 cups water
1 package yeast
1 tsp sugar

When dissolved, add
2 cups flour.
Whisk well until smooth. Cover and go away, like for a day, or more in the winter. In about 24 - 48 hours you should refrigerate this concoction for use later.

Some additional notes:
If you decided that my non-metallic specifications weren't worth heeding you are probably wondering why I said use no metal. Well, if you take your now fermented biga and use a metal whisk you will be peeling a very rubber-like, tenacious goop off of your whisk. Believe me, you won't do this twice.
Before using the biga, pour off the alcoholic liquid on top, then blend smooth the remaining batter as the flour settles.
The biga must be replenished from time to time, whether you use it or not, other wise the yeast will die off the culture will just go rancid. The biga is best kept very cold until you need it. If you use it every week you may want to give it a boost by leaving it at room temperature about 12 - 18 hours after you replenish it before refrigerating it. It will ferment slowly even if cold if use infrequently. Your handling and storage will be cause for variations but in time you know when your biga is ready for use or replenishment.

Use this biga for any recipe that calls for sour dough cultures, starters or bigas. "A fermentation by any other name smells as sour. "