Lactic bacteria and Wild yeast are predominate in healthy Starter, and it is important to maintain this balance. The Starter should smell sour, but not off, and be active, - which are two most important signs of healthy Sourdough Starter.
Lactic-acid Bacteria in Sourdough Starter feeds on starch and carbohydrates of the flour, hence lowering the carbohydrate content of the bread and its glycemic index. In well-developed Starter, Lactic-acid Bacteria also protects the bread from growing mold.
Phytates contained in grains prohibit the mineral absorbtion as zinc, iron, magnesium, cooper and phosphorus. Phytase enzyme activated in Sourdough Starter, breaks phytates down, improving the nutritional content of Sourdough bread. The longer you ferment the dough, the more minerals will be "freed up" as the phytase breaks phytates down.
Wholegrain flours contain less phytates than white flour, therefore, require less time of fermentation to make the nutrients in flour available. This is particularly important for Wheat flour, that should not be fermented for too long, as it gets sour and spoilt quickly.
Through traditional longer fermentation most of the gluten contained in the flour is being broken down. As Wheat flour can not be fermented for long times, choose the ancient wheat grains, containing very low amounts of gluten.
In each fermentation cycle, healthy Starter reaches its peak of activity (rises), then falls back to its normal level. If the peak is missed or not pronounced due to cool room temperature, or the presence of other microorganisms in the Starter that dominates Wild Yeast and Lactic Bacteria, - brown liquid will form on the top. Never throw it away. Mix it in and add more flour and water to "feed" the Starter, then leave it for 4-8 hours. At warm temperatures above 25 C, 4 hours is enough for healthy Starter to reach its peak.
The Starter can "learn" to work at cooler temperatures, which happened to all my Starters within a year after we relocated from QLD to VIC few years ago. It takes 1 hour for my Starters now to reach their activity peak at below 20 C room temperature.
It is very important to use Wholegrain Flour to "feed" the Starters to keep them healthy. White flour is too poor in nutrients to promote healthy microorganisms balance in Starters over a long time. Fresh home-milled flour is the best, and I treat my Starters with it at least once a month, if I can not "feed" it to them all the time.
The Fermentation Cycle is the time between "feeds", when Lactic Acid Bacteria and Wild Yeast grow and multiply in the Starter, and, - if left for too long, - undesirable bacteria and microorganisms may start growing ("over fermented", "soured" Starter). It can be cured, but better avoid it reaching this stage.
Wheat (Spelt) Starter is most vulnerable to getting overly fermented, as its gluten is very prone to breaking down. When not in use, keep it refrigerated at all times and "feed"twice a week. If you can not "feed" it that often, keep it in thicker consistency and "feed" once a week.
Working with traditional Wild Yeast Sourdough Starter can be more time consuming than using commercial yeast. You need to be patient, and after some time you will start recognizing its cycles and "feeding" needs better. It is similar to having a pet, whom you get to know better the longer you have owned and looked after.
Normally, the Starter that is about to starve has thick and fluffy upper layer with collapsed bubbles (showing as small holes on the surface), and the liquid forming at the bottom, which will rise to the top if you don't "feed" it immediately. The Starter is about to reach its peak and needs "feeding" to avoid getting sour. It will smell pleasant, but not sour yet, as the yeast levels are at their highest but the acid is not built up yet. Such Starter can be used for baking, or "fed" and put away until next time use.
The best suited for baking Starter is before it has reached its peak, or has just started to show bubbles.
Soured Starter can not be used for baking. If you missed the peak of your Starter's activity, and it has been over fermented (built up too much acid), "feed" it again and wait until the balance of its microorganisms returns back to normal.
If the Starter is left to sour without "feeding", the yeasts will start dying and smell will change to unpleasant. Although it can still be revived, the process could be complex and time consuming.
If the Starter is left neglected for too long, the mold will grow, showing as small white dots on the surface. It can no longer be used, or revived. Mold and unpleasant smell are the only signs of "dead" Starter.
If your Starter is not very active but smells good, "good" microorganisms dominate in it, so keep "feeding" it and adjust its consistency (water to flour ratio) and room temperature.
If you bake often and keep your Starter at room temperature, "feed" it once a day (Rye), and twice a day (Spelt and Wheat).
To "feed" the Starter that is kept refrigerated and not used for baking, take it out and let it go through full fermentation cycle (4-8 hours depending on room temperature and letting it reach the peak of its activity), then add a small amount of flour (1 tea spoon to 1/4 cup of Starter), mix, cover lightly and put back to fridge.
Active Starter ready to use for baking:
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