| YEAST is a microbe (a single celled fungus really) that causes the beer to ferment (producing alcohol) during the brewing process. It takes a couple of weeks to complete the fermentation process, after which time the beer gets bottled and can carbonate. YEAST eat sugars, which is why extra sugar is added to the beer just before bottling, causing the beer to carbonate. There are top fermenting yeast that like warmer temperatures used for ale, and bottom fermenting yeast used in lagers that prefer colder temperatures. |
