Yeast (baker's / brewer's)

Baker's and brewer's yeast are strains of a single microscopic fungus, Saccharomyces cerevisiae — the leavening and fermentation organism behind risen bread, beer and wine. Sold as compressed fresh cakes, dried granules or creamy liquid slurry, it is the foundational culinary fungus: a living single-celled workhorse that turns sugar into carbon dioxide gas, alcohol and a bouquet of aroma compounds, and has done so in kitchens and breweries for thousands of years.