How does yeast feed on the water
How and why does yeast grow and feed on the water? My children and I have been making yeast rolls and they keep asking why it expands,I don't know how to answer this and they are still waiting for an answer.
Best Answer
Yeast does not feed on water, it feeds on carbohydrates, i.e. sugar and flour.
If you got the impression that it feeds on water, it might be because you used dried yeast, which is basically dormant yeast that gets reactivated by the water.
If you use lukewarm water alone to activate your yeast, it feeds on the food remains from the growing medium, if you add a pinch or two of sugar (not too much!), you will see more vigourous bubbling.
Yeast has two types of metabolism, aerobic (with oxygen present) and anaerobic (without oxygen). Both metabolize sugar and create CO2 (the bubbles), the aerobic one also produces water, the anaerobic alcohol (think about wine, for example). The latter is also the predominant process in baking.
For a more kid-friendly explanation, which mine loved:
Yeast eats sugar and burps CO2. Those bubbles get trapped in the dough and make it fluffy.
A few links with kid-oriented material and experiments:
http://sciencewithme.com/what-is-yeast/
http://redstaryeast.com/science-yeast/what-is-yeast/
http://redstaryeast.com/science-yeast/yeast-experiments/
http://www.scientificamerican.com/article/watch-yeast-live-breathe/
http://www.kidsdiscover.com/teacherresources/science-of-yeast-for-kids/
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What does yeast do with water?
It is in the presence of water that gluten forms. Water serves as a solvent and dispersing agent (for salt, sugar, and yeast). Water is necessary for yeast fermentation and reproduction; softer doughs will ferment more quickly than dry doughs. Water is responsible for the consistency of bread dough.What does yeast feed on?
Yeasts feed on sugars and starches, which are abundant in bread dough! They turn this food into energy and release carbon dioxide gas as a result. This process is known as fermentation.Does yeast eat water?
Like other living organisms, they need food and water. So by putting them in a moist environment with nutrients (such as sugar), they become "active."Does yeast absorb water?
The cells of instant dry yeast are porous to absorb water and can be put directly in the flour without waiting for the yeast to hydrate. However, so that the yeast does not have to compete with the sugar or other ingredients for moisture, it is best to mix the yeast in only a portion of the flour.Fermentation of Yeast \u0026 Sugar - The Sci Guys: Science at Home
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