While it is absolutely possible to brew beer using bread yeast, it behaves in slightly different ways than the beer yeasts you are probably used to and may produce less than ideal results.
It is absolutely possible to make homebrew beer using bread yeast. For the most part, bread yeast and beer yeast are the exact same species and undergo the same chemical process used to convert sugar to alcohol: ethanol fermentation.
Just like any other yeast, bread yeast produces ethanol through ethanol fermentation. In addition, both bread yeast and beer yeast can synthesize trace amounts of higher alcohols like propanol and butanol as by-products of ethanol production.
Although adding extra yeast will not solve all the reasons for stuck fermentation, If your stuck fermentation is due exclusively to a lack of yeast, adding dry bread yeast will certainly restart fermentation.
When it comes to comparing bread yeast and beer yeast, there are a number of factors that differ between the two categories.
– History – Genetic – Flocculation – Attenuation – Flavor Profile
If you decide to brew with bread yeast, treat it as an experiment and a learning opportunity to become more aware of the role that yeast plays in the brewing process.
I recommend pitching the same amount of yeast you would use in a recipe that calls for normal beer yeast and brewing at a slightly colder temperature than you’re used to.
Bread yeast will finish primary fermentation faster than beer yeast, but the exact length of fermentation will depend on the exact strain you use. To overcome this problem, you’ll want to rely on visual cues to let you know when your brew is done fermenting.
Most yeast produce similar levels of carbon dioxide when given enough time, so your best bet is to add the same amount of yeast as you normally would and tweak the formula based on your own observations and experiments.