Sourdough Starter
Instructions
Day 1:
In a large glass or ceramic container, combine 60 grams of whole grain flour (rye or wheat) with 60 grams of lukewarm water (ideally at around 26-27°C or 78-80°F).
Stir well to make sure all the flour is incorporated and there are no dry patches. The consistency should be like a thick batter.
Cover loosely with a cloth or plastic wrap and let it sit in a warm place (about 21-24°C or 70-75°F) for 24 hours.
Day 2:
You may or may not see some bubbles or activity in your mixture. Either way, discard about half of your starter (approximately 60 grams).
To the remaining starter, add 60 grams of flour and 60 grams of lukewarm water, and stir well.
Cover again and let it sit in a warm place for another 24 hours.
Day 3:
By now, you should start to see some signs of fermentation: bubbles, a slightly puffed-up appearance, and possibly a sour or yeasty smell.
Again, discard about 60 grams of your starter, then feed with 60 grams of flour and 60 grams of lukewarm water.
Cover and let it sit in a warm place for another 24 hours.
Day 4 and onward:
Continue this process of discarding half and feeding your starter once a day. Over the course of a week or so, your starter should become reliably bubbly and double in volume within a few hours of feeding.
Remember, it's normal to see a layer of liquid (known as "hooch") on top of your starter if it's not fed regularly. It's an indication that your starter is hungry and needs feeding.
Once your starter is reliably rising and falling, it's ready to be used for baking!
One final note:
Always ensure to reserve enough starter before baking, so you don't inadvertently use up all your starter. You'll need at least 60 grams left to continue feeding and maintaining your starter.
This process should guide you to a healthy, robust sourdough starter. Happy baking!
What's Happening in this initial phase:
When you mix flour and water, the naturally occurring yeast and bacteria in the flour and surrounding environment start to feed on the sugars present in the flour. The yeast produces carbon dioxide (which makes the mixture rise), and the lactic acid bacteria produce lactic and acetic acid (which gives sourdough its tangy flavor).
The goal of feeding your starter (adding more flour and water) is to gradually build a stable colony of yeast and bacteria. The process of discarding half of the starter before feeding is important for maintaining a balance of yeast, bacteria, and food. If you didn't discard, the amount of starter would increase exponentially, requiring massive amounts of flour for feedings!
Once your starter is active, it will require regular feeding. If you're baking often, you can keep it at room temperature and feed it daily. If you're baking less frequently, you can store it in the refrigerator and feed it once a week. Remember, the starter is a living culture, and keeping it healthy requires regular care.
Always use clean utensils when handling your starter to prevent contamination from unwanted bacteria or mold. If your starter develops any off-smells (other than the acidic smell that is characteristic of sourdough), changes in color, or mold, discard it and start over.
Finally, be patient. Creating a robust sourdough starter can take time, but the delicious bread you'll be able to bake is well worth the effort!
Still curious? Here's more science:
Creating a sourdough starter from flour and water involves a fascinating interplay of microbiology and biochemistry. The flour-water mixture provides the environment for a symbiotic culture of wild yeast (Saccharomyces cerevisiae) and lactic acid bacteria, mainly from the genus Lactobacillus.
Here are some additional scientific details about the process:
Flour Composition: The type of flour used impacts the success of the starter. Whole grain flours are often recommended because they contain more nutrients and a wider range of yeasts and bacteria than white flour. This is because the milling process that produces white flour strips away the bran and germ of the grain, where many of these microbes are found.
Wild Yeast & Lactic Acid Bacteria: The yeast in your starter metabolizes the sugars in the flour, producing carbon dioxide gas, which causes your dough to rise. But it's not just yeast at work in your starter. Lactic acid bacteria also play a crucial role. They produce lactic and acetic acid, which gives sourdough its distinct tangy flavor. The acidity created by these bacteria also helps to prevent harmful microbes from colonizing the starter.
Enzyme Activity: Enzymes in the flour and those produced by the yeast and bacteria break down complex carbohydrates (starches) in the flour into simpler sugars, which can be metabolized by the yeast and bacteria. This process is called saccharification.
Temperature: The temperature at which you keep your starter affects the rate of fermentation. Yeast activity increases with temperature, up to a point. A cooler environment will slow down the fermentation process, while a warmer one will speed it up. However, if the temperature is too high (above about 35°C or 95°F), it can kill the yeast and bacteria.
Hooch: Sometimes, you might see a layer of liquid on top of your starter. This is often referred to as "hooch" and is a byproduct of fermentation, mainly consisting of alcohol and acids produced by the yeast and bacteria. It's a sign that your starter is hungry and needs to be fed. You can either pour it off or stir it back in before feeding your starter.
Maintenance & pH: As you feed your starter, you're not only providing food for the yeast and bacteria, but also maintaining an appropriate pH level. The acid produced by the bacteria keeps the culture at a slightly acidic pH, which helps to prevent the growth of unwanted microbes.
Remember, the goal of maintaining a sourdough starter is to create a stable, symbiotic culture of yeast and bacteria that can reliably leaven bread and impart the characteristic sourdough flavor. It's a fascinating mix of science and art!