Is baker's yeast considered a plant-based ingredient?

The answer

Baker's yeast is a single-celled fungus, not an animal product, so the yeast itself is generally treated as a plant-based ingredient. What can differ is the packaging: some products add emulsifiers or carriers, so check the ingredient list on your specific package. Fresh, active dry and instant yeast are all the same species. Other ingredients in a recipe, such as milk, butter, eggs or honey, are what usually make a bread non-vegan.