Have you heard of monster dough? Some people call it sourdough. It is a dough recipe where you put water, flour and dry yeast in a jar. Other ingredients may be added depending on how you want it to taste. Yeast in the flour thrives in this mixture causing the process of fermentation and expansion. Given time, the amount of dough will increase.
You can keep monster dough and use it for baking bread, biscuits, muffins, etc.
You can perpetuate your supply by continuing to add flour and water as you use it up. The yeast is active and will always cause the dough to swell larger than what you start with.
Some call it friendship dough and say that you should share it with others, but we need to be careful about what we give to our friends. The University of Wisconsin-Madison reported that:
Recent nationwide foodborne illness outbreaks have been linked to traditional bread-making ingredients: first, contaminated flour was tentatively linked to the presence of E. coli in Nestle cookie dough that sickened at least 69 people in 30 states and led to a nationwide recall of prepared, refrigerated cookie dough in 2009; more recently, thousands of eggs were recalled in 2010 due to possible contamination with Salmonella. Since no one wants to share illness as they share friendship bread starter, or sicken their family as they prepare an extended-rise bread, it’s time to ‘think safety’ when preparing, or sharing, these products.[i]
On the other side of the dough world, you have unleavened dough used to make various kinds of flatbreads. It does not rise and expand in the way that dough with yeast will grow.
In the Exodus, God sent Moses to lead the Jewish people out of their slavery in Egypt. On the night of the Passover, they were given instructions on how to prepare for a quick departure. Including their travelling clothes and gear, they were to eat a meal that included unleavened bread. You could prepare it quickly since it did not require the time that yeast needs to cause the bread to rise.