Cindy & Sam @ 城市農莊

為何我用天然酵母酸酵種(sourdough)做麵包? 因為這樣比較 "健康" !! (上圖 sourdough 長好的組織圖)

天然酵母＝無人工添加物、100％健康

大家都希望吃得更健康更自然. 傳統烘焙常用的人工添加物：益麵劑、改良劑…等，長期累積必然對身體造成傷害.

天然酵母是以更貼近健康的水果醋、乳酸菌…等食材及天然酵母來製作麵包。「天然酵母」是由覆著於穀物、果實上和自然界中多種細菌培養而成。因為自然界中存在很多種菌，不同國家不同地方都不相同，所以稱為天然酵母。天然酵母比一般酵母風味更佳，因為麵粉充分吸收水分，熟成時間長，另一方面是天然酵母為多種菌培養而成，在烤焙時，每一種菌都會散發不同的香味，讓麵包的風味更多樣化。

天然酵母製作：

將有機葡萄乾及蜂蜜泡水約10-14天培養天然菌種。罐上蓋保鮮膜，防止小蟲飛入，用牙籤刺出小洞透氣。圖片是完成品，葡萄乾浮在上方，罐內有許多的氣泡，表示菌種非常有活力。

下圖下面的線是第一次將麵粉和入上圖的葡萄乾菌種液內的高度(晚上9點)。上面的那條線是發酵12小時後(次日早上9點)的結果 -- 長約3-4倍大, 菌種非常有活力。

取出上圖養好的部份菌種麵再加上麵粉及水攪拌均勻。

攪拌好了叫做 chef dough，放如乾淨盒內，如下圖。晚上9點。

發酵12小時後(次日早上9點)的結果 -- 長約3-4倍大, 菌種非常有活力。

下圖可以清楚看到 mother dough and chef dough 成長的變化。紫色的線是高度。

下圖：終於做成 first sourdough -- 由開始養菌種液算起，也有16-7天了。酸酵種還沒完成。不過，快了，這次發完就成功囉!

發好後太興奮，直接拿去做麵包了，忘了拍長好的高度照片。不過，基本上就像上面那幾個圖一樣，會長3-4倍大。下面是長好的組織圖。一手將盆子倒過來，另一手拍照，手會微抖，焦點沒對得很好。

Why Sourdough? http://www.ranprieur.com/misc/sourdough.html

Commercial "baking" yeast is a single kind of organism that belches a lot of gas really fast and transforms grain into something that's even less good for you. Sourdough is two organisms, wild yeast and bacteria, in symbiosis. Together they transform the grain to make it more healthful, more digestible, and also resistant to getting moldy or stale. Many people with wheat allergies or "yeast" allergies have no problem eating real sourdough. And it's free!

How Does It Work?

With sourdough, you are keeping and feeding a population of friendly yeast and bacteria, called a "culture", or a "starter". The population rises and falls, depending on where you keep it and what you feed it. When you make a loaf of bread, you are carefully managing a population explosion. The sour flavor comes from acids made by the yeast and bacteria, and when it gets really strong, that does not mean the sourdough is strongly active, but that it is depleted, that the population has already eaten its food and collapsed.

Why Naturally Leavened Bread? http://earthstar.newlibertyvillage.com/fermentedbreads.htm

The fermented quality of naturally leavened bread has several healthful advantages over yeasted breads. Yeasted breads are risen very quickly by a refined yeast strain that has been isolated in a laboratory under controlled conditions, using a process we could never duplicate in our kitchens.

In the process of making sourdough bread, during the rising time (called proofing), bran in the flour is broken down, releasing nutrients into the dough. In particular, the phytic acid (phytin) in grain needs to be 90% neutralized in order for the minerals, concentrated in the bran, to be absorbed by the human body. According to the experiments done in Belgium, phytin can be neutralized by natural bacterial action and to a lesser extent, by baking. In naturally leavened bread, the combination eliminates all phytin, while in yeasted bread about 90% remains.

Furthermore, with sourdough bread, complex carbohydrates are broken down into more digestible simple sugars and protein is broken down into amino acids. Enzymes develop during proofing which are not lost in baking since the center of the loaf remains at a lower temperature than the crust.

It’s the fermentation, partly from lactobacillus, that makes eating good quality bread an aid to digestion of all complex carbohydrate foods including other grains, beans, and vegetables. It helps restore the functioning of the digestive tract, resulting in proper assimilation and elimination. These beneficial bacteria help control candida albicans, whereas baker’s yeast is a pro-candida organism. This is a brown bread that truly is "the staff of life" as it enhances the whole immune system.

Allergies?

People with allergies to commercially yeasted breads may not have the same sensitivities to naturally leavened whole grain sourdough bread. The cause may be either the wheat and/or the yeast. Often, people who are sensitive to yeasted white bread do not react to whole wheat bread. Others, who are sensitive to whole wheat bread, do not react when the leavening used is natural sourdough starter, and especially when the flour is freshly ground. Another approach is spelt flour instead of wheat flour. Spelt is the original strain of bread wheat from Europe, and it has not been hybridized. Rye flour is another choice that is nice used in small amounts.

Digestibility

Bread and grain-based diets, especially at the beginning, give the illusion that they do not readily digest. Natural leaven bread, because of its inherent beneficial ferments, slowly recreates the population of friendly lactobacillus digestive bacteria in the absorption tract. The end result is a recovery of digestion and proper elimination by the effective action of friendly bacteria. Natural leaven bread provides more stable nutrition than that obtained mechanically by non-fermented (and thus non- pre-digested) bran and other raw or cooked roughage diets, since these only succeed in physically abrading and irritating the colon.

Modern Breads as a Potential Cause of Cancer

You may be surprised to learn that conventionally yeasted breads have been linked to cancer. True sourdough bread is naturally fermented. It is yeast free and requires several hours to rise before baking. In contrast, conventionally yeasted bread uses a high concentration of an isolated yeast strain to make bread rise within minutes. In an article, published in 1984 in East-West Journal, Ronald Kotsch describes why conventionally yeasted bread contributes to disease.

"In (conventional) yeast fermentation, the starch cells of the bread actually explode. The patterns they form are identical to those of cancer cells. According to French researcher Jean Claude Vincent, the bio-electrical energy of the dough also is identical to that of cancer cells."

German and Swiss researchers concur with Vincent that this fast-acting yeast sends an electrical message to the body for the cells to mimic this exploding replication. This is cancer. Beyond these facts, sourdough bread may win you over by its taste alone. It is wonderful, chewy, old-world bread.

基本上上述關於酸酵種的好處 -- 易消化、延緩麵包老化、增加麵包風味…等應該都是可信的，但我不清楚關於癌症 cancer 部份的可信度有多高。

不過因為自己的健康因素，以及酸酵種的諸多好處，還是決定用 sourdough 的方式製作麵包。可惜的是，製成的麵包酸味較重，小孩難以接受，所以只好中和一下，基本上以 sourdough 為主，再加上一些商酵- active dry yeast or instant yeast (約原食譜的1/6). 這樣的做法，一來可以減低酸味，二來還是保有帶給身體的好處。

另外，sourdough 附加好處是: 可增加麵包的彈性 -- 口感好，並延綏麵包老化速度，可將麵包壽命多延長2-3天。(不含任何人工添加物(防腐劑)的麵包壽命其實只有6-8小時。第一天最好吃, 第二天一定沒有第一天好吃，第三天還可勉強裹腹充飢，第四天碰都不想碰了。)

若是您家裡的麵包吃上一、二個星期都一樣鬆軟，小心，您已經吃進不少防腐劑了喔!