What do bread and ginger beer have in common?

They are both made with yeast (Saccharomyces cerevisiae) – a living organism that produces ethyl alcohol and carbon dioxide when allowed to grow in suitable conditions. This is an example of anaerobic respiration, or fermentation, which produces a small amount of energy (ATP) compared to aerobic respiration. An animation of the process of ATP production during fermentation is here.

In bread making, the carbon dioxide gas is captured in a gluten matrix produced by working the flour together with water into a dough. When the dough is baked, the yeast is killed, the small amount of alcohol evaporates and the carbon dioxide produces a light, fluffy loaf of bread. More about the science of bread making here.

When making beer, sugar is added to ‘feed’ the yeast and carbon dioxide bubbles are produced, along with a small amount of alcohol (less than 0.5% in the bottle we will produce). The lemon juice and ginger added to homemade ginger beer is for taste.

3 thoughts on “What do bread and ginger beer have in common?

  1. brittgow Post author

    Today in the prac i learnt that the high concentration of surcose equals a faster respriation rate of yeast. At the moment we are testing if the salt concentraion has an impact on the rate of respriation. =)

  2. Hannah

    i learnt from this experement that the higher the sucrose level the higher the respiration rate when yeast and sucrose are combined in a test tube woth a balloon on it (the balloon is to collect the carbon dioxide released) when we added oil to our consentration the respiration rate lowerd!!

  3. Kara

    today in biology i learnt how yeast, the consentrated form we use in things like bread and ginger beer is formed. Yeast is actually all around us; in the soil (though it isn’t plant, it’s a fungus!), in the air..everywhere. A yeast cell is taken and grown and it buds/multiplies un till it is big enough for us to use.

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