The Beer Brewing Process – Step 4 : Fermenting

From regular barley cereal, your initial ingredient has undergone several changes by the time you reach step 4, Fermentation. Your barley has been changed into malt (Malting), then into mash (Mashing) and then into liquid wort (Lautering).  For fermenting, you will use the sterile, flavored wort that’s the result of the previous step, Boiling.

Beer fermentation is the process where you add yeast to the wort in order to convert the sugars in it into alcohol and carbon dioxide.  But fermentation isn’t as easy as it sounds.  It usually takes a minimum of 7 days to as long as a month, depending on the type of yeast and the type of wort being used.  Here are the usual steps when fermenting beer.

• Pitching – Pitching is simply the term that brewers use which means to add the yeast to the wort.  Most brewers use cylindro-conical fermenters or vessels which have cylindrical openings and conical bottoms to facilitate the easy pouring of the yeast into the wort and easily allow the yeast and other solids to be flushed out from the bottom.  Some vessels are open at the top to make it easy to harvest from the top-fermenting yeasts.
• Lag Phase – Once the yeast is mixed with the wort in the vessel, you can expect the yeast to aggressively reproduce using the sugar from the wort.  The lag phase is simply the difference between the time that the yeast has been added to the wort and the time the yeast starts fermenting.  To decrease the lag time, brewers usually make use of yeast starters.  Brewers pitch the yeast onto sugar first increasing the yeast cell count and already initiating yeast cell reproduction even before adding them to the main wort.  By the time you add the already active yeast cells into the main wort, you’ve already shaved off a significant amount of time from the process.
• Fermentation – Once you see bubbles and foam forming on top of the beer, you will know that fermentation has started.  Fermentation is highly dependent on the temperature of the yeast.  Ales fermentation temperatures range from 18-24C while lagers need 8-14C.  An indication that fermentation is complete is when you see the yeast form into clumps and flocculate (settle) at the bottom of the container.  To be sure, brewers constantly check the specific gravity of the beer is stable for consecutive days.  Once you are sure that fermentation is complete, the brewer can decide if it wants to further condition the beer or send it straight to bottling and kegging.