What's In The Water?

Water is a key factor in creating and maintaining a healthy starter. It may seem like no big deal but the kind of water you use in feeding your starter and baking your bread can have a great effect on your success. I learned early on that tap water prohibited my yeast from rising but I also discovered that I had little success using my filtered water from the fridge. I began buying bottled water from the store and have been using that ever since. I leave it on my counter because it seems my yeast performs the best when the water is at room temperature.

For Christmas my husband purchased a great book for me, Bread, A Baker's Book of Techniques and Recipes by Jeffrey Hamelman (you can purchase it here from Amazon). This book has been an excellent resource for me as a novice baker. I was pleasantly surprised to find a lot of information and even recipes using a levain or sourdough starter. I'm still experimenting with some of his methods and techniques and will share what I learn later on but he had an interesting section on water that answered some of the mystery for me about water:

1. It is in the presence of water that gluten forms

2. Water serves as a solvent and dispersing agent (for salt, sugar, and yeast)

3. Water is necessary for yeast fermentation and reproduction (and softer doughs will ferment more quickly than dry doughs).

4. Water is responsible for the consistency of bread dough.

5. The temperature of water can be varied in order to obtain dough at the correct temperature.

The degree of hardness in water is an indication of the amount of calcium and magnesium ions present, expressed in parts per million (ppm). Soft water has less than 50 ppm, while hard water has more than 200 ppm. Generally, water of medium hardness, with about 100 to 150 ppm, is best suited to bread baking.

These minerals provide food for the yeast, and therefore can benefit fermentation. If water is excessively hard, however, there is a tightening effect on the gluten, as well as a decrease in the fermentation rate (the minerals make water absorbtion more difficult for the proteins in the flour). On the other hand, if water is excessively soft, the lack of minerals results in sticky, slack dough. Generally speaking, most water is not extreme in either direction, and if water is potable, it is suitable for bread baking.

In the creation of a sourdough  or levain culture, there is another consideration (for water). If the water is too highly chlorinated, the chlorine can have a negative impact on the culture by inhibiting the metabolism of the developing microorganisms. In this case, simply leave a bucket or jar of water out overnight, uncovered. By the next day, most all the chlorine will have dissipated. Alternatively, filtered water can be used.

The amount of acidity in water, expressed as pH (potential hydrogen), also has an effect on fermentation, Hard water is generally more alkaline than soft water, and can decrease the the activity of yeast. Water that is slightly acid (pH a little below 7) is preferred for bread making.

So it seems that my tap water didn't work because it was too highly chlorinated and my filtered fridge water didn't work because it contained too much soft water. It makes me feel a little like Goldilocks but I'm happy I found a bottled water that seems to fit just right.

One more note:

My sister made a discovery of her own, not in regards to water but in regards to chlorine and harsh cleaning chemicals. Over the past year I have given her several sourdough starts which she had trouble keeping alive. She learned that distilled water didn't work nor did her tap water but even after she bought bottled water she was still having trouble. Then in a moment of inspiration she purchased new jars for her starter and voila, that did the trick. She suspects that the cleaning agent she uses in her dishwasher remained on the inside of her jars even after being rinsed and dried and that it was prohibiting her starter from rising. She now washes her jars by hand. I haven't experienced this problem myself but it was interesting and may be helpful to someone else so I thought I would share.