Pre ferments make better bread!
A pre ferment is essentially anything used on the way to building a sourdough or other type of bread, which assists the leavening process. For example, a 'sponge' made of flour, yeast and water is a type of pre ferment. In this article, I'm going to walk through the basic sponge method, and show the best ways to incorporate sourdough into the spongemaking process.
Pre Ferments also are like natural bread improvers - apart from increasing the activity of the yeast, they serve to elasticise the gluten, which gives you a better rise.
 For a working example of this, the Continental bread recipe uses only a smidgin of yeast, yet rises like it has much more. This is simply due to the effect pre fermentation has on the acid balance in the dough. A well seasoned pre ferment will make the dough slightly acid, and this will help the gluten to soften.
Another advantage of using a pre fermentation process in doughs is that the living yeast culture is rapidly multiplying in an ideal environment for it to do so - thereby providing a 'kick' to the leavening in the dough.
Yeast - fresh vs powdered
Most prefermentataion processes involve cerviseae yeast. (Note: not all of them do - and I'll be showing how to do a pre ferment with sourdough only later in the article). There are two different kinds of yeast available.
If you are lucky enough to have fresh yeast available to you, consider it a blessing. Mostly these days fresh yeast is only found in bakeries - there's too much handling and wastage to bother most shopkeepers. Home bakers, while a growing movement, do not a mass market make!
Then there's the dry stuff. Any recipes in the site using yeast default to powdered yeast as the type I've used. Double the amount I've specified in the recipes if using fresh yeast.
In my opinion, powdered yeast is best if it is in a 'bulk' container (maybe 250 grams?), rather than 15g sachets. You can use very small amounts this way, and over time you'll get to know the volumes. I find sachets inconvenient, because I rarely need all they have in them. What price convenience? For me, 'inconvenience' is more convenient.
Making a 'sponge'
A 'sponge' is a baker's term referring to the creation of an active yeast colony, using flour and warm water as the medium. This is made as a batter, which is allowed to ferment until it becomes active, and physically resembles a 'sponge' when it's active. This sponge is then built into a dough using more flour, water, and a little salt.
It is also possible to apply the sponge technique to sourdough ferments, without refined yeast being added at all. This is especially important when using dry dough sourdough or old dough sourdough as the levain. It also helps a liquid starter along too, though.
Following are three slightly different methods of making a sponge. In other articles, I intend also to cover other types of preferment, including poolish and biga, among other things.
Yeasted Sponge
Sift approximately a quarter of the total flour weight called for in the recipe, and whisk it together with half the water measurement called for in the recipe. Roughly, this will be a ratio of one to one - which equates to a thick batter. 
Make sure the water is warm. Warmer than you.
Beat, using a heavy type of whisk, or a fork. Add in the yeast measurement from the recipe as you go.
If you are simply making a sponge and don't have a recipe, I work on 1/2 percent of the flour weight when making 'semi sourdough' (semi leaven). Regular yeasted breads have between 1 and 2 percent yeast compared to flour weight. So if it's a kilo of flour, half a percent will be five grams. You get the idea.
Your container should have plenty of space for expansion - the sponge will double in volume or more in about half an hour.
When it's at this point (and this will be quite obvious) it's time to build your dough.
Yeasted Sponge with sourdough culture
This is a bit different, because you want to encourage the sourdough yeasts, and then 'highlight' or boost them with yeast. The reason for this is that the cerviseae strain of yeast will rapidly overpower the sourdough yeasts and enzymes and bacteria, so we need to give them a head start.
 The day before you plan to bake, take the measured amount of your sourdough starter for the recipe, put some warm water (warmer than you, but not hot) and flour in a container (at least twice the size you need for the ingredients). Whisk with a heavy implement until it's a smooth, thick batter. Leave overnight at room temperature. It'll rise a bit - but not as much as the yeasted sponge in the previous paragraph.
Next day, add in the yeast and whisk again. It'll double in size one more time, and then you can go ahead and build your dough.
Sourdough Sponge
Exactly as per the previous paragraph, except no yeast!
Other common preferments include Poolish and Biga. Articles about this follow soon, but in a nutshell, the pre fermentation technique allows you to activate the yeasting process without the weight of the dough holding those tiny yeast colonies up with the hard work of lifting. This means that the yeast, as a living thing, can multiply more quickly and therefore do it's job better.
Another salient point in this exercise is that dough leavening times, even with sourdough, can be reduced substantially by using this technique. I add the rider here that you will need to 'read' the sponge correctly, otherwise you'll be simply adding a process to your breadmaking.
Fermentation, though, always improves flavour. Our bodies respond well to fermentation too. So go forth and multiply!
Other articles of interest in this section include:
Tips & Tricks
Until next time,
Happy Sourdough Baking!
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