Levin/organic bread is raised by natural yeast. How is that yeast produced?!
Levin/organic bread is raised by natural yeast. How is that yeast produced?
Answers:
This is a really long answer, but I hope it helps. I REALLY love to bake with natural yeast, and have five different strains in my fridge!
Natural yeast is wild yeast, that is, yeast captured from the air. It’s essentially the same thing as sourdough yeast, but don’t let that scare you. Not all sourdough starters are ultra tangy. I captured one here in the Midwest that has a sweet twist and smells like aplle cider. The species used for baking include Saccharomyces exiguus and Saccharomyces inusitatus, but in any one sourdough starter there may be several species of wild yeast, depending upon where and when it was collected, and what ingredients were in the initial batter.
It’s not only the yeast that makes the difference, but also the bacteria that accompanies the yeast. For example, the sourdough breads of San Francisco have a unique flavor in part because of a species of lactobacilli that can only be found in the ecosystem surrounding the Bay area (which makes it REALLY tangy!). Similarly, Alaskan sourdough pancakes have a special flavor and texture because of the lactobacilli found in that environment.
There are a variety of methods that may be used to capture wild yeast: some use mashed potatoes or grape skins, others include fresh hops or rye meal, and the liquid varies from water to milk to a combination. A really terrific, detailed description can be found at www.howstuffworks.com/sourdoug... but here’s summary:
Mix two cups of flour and two cups of water in a glass or pottery bowl. Lay a double layer of cheesecloth over the top (attach with a large rubber band if you think it might blow off). Let the bowl sit outside in a sunny spot for the day. The wild yeast floating in the air will make its way to your flour/water mixture. It will then start growing and dividing.
After 24 hours, bring the bowl inside and pour off about a cup of the mixture and feed it with another cup of flour and another cup of water. In a few days, the mixture will become frothy as the yeast population grows. The froth is caused by the carbon dioxide that the yeast is generating. Leave the starter on the kitchen counter for five days. As the starter ferments, it will develop a strong aroma -- bready and alcoholy and not particular appetizing. Feed it every day or two by dividing it in half and adding a cup of flour and a cup of water to one half of it (you can throw the other half away). When you see a watery substance floating to the top, stir it. Sourdough bakers call this "hooch." Over the week the starter became a thick liquid, like pancake batter. It will be slightly yellowish.
How you use the yeast is a whole ’nother question! Here’s a brief annotated bibliography.
Alaska Sourdough by Ruth Allman (Alaska Northwest Books, 1976, ISBN 0882400851). Mrs. Allman lived in a lodge north of Juneau for many years, so she’s the real deal. This book includes 95+ recipes, including several different recipes for starter
Classic Sourdoughs: A Home Baker's Handbook by Ed Wood (Ten Speed Press, 2001, ISBN 1580083447). This book is an updated version of World Sourdoughs from Antiquity (1996, ISBN 0898158435 ) by the same author (which is the edition I own). Either book is an excellent resource for sourdough baking, especially for those who want more than recipes.
Sourdough Jack’s Cookery and Other Things by Jack Mabee (Argonaut Press, 1970, out of print) If you want real sourdough cookery by an authentic Alaskan cook, this is your book. Although out of print, copies of the book regularly appear on eBay. Great stories, pictures, and Alaskan lore, and detailed, step-by-step descriptions for every recipe.
Source(s):
This is adapted from lecture notes for a workshop I gave on natural yeast baking/sourdough.
Natural Yeast
Make a thin batter of flour and lukewarm water. Let it stand in a warm place until it ferments and is full of bubbles. 2 cups of this liquid yeast is equal to 1 cup of old yeast Yeast is good when it is foamy and full of beads, has a brisk pungent odor and has a snap and * vim. It is bad when it has an acid odor, is watery and has a thin film on top.
* vim: lively or energetic spirit; enthusiasm; vitality.