Homebrewing 101: Primary and Secondary Fermentation (Part 3)
Now that your beer has been brewed and the yeast pitched into the cooled wort… one must be patient and wait.
As the yeast does its work, a foam is formed on the top (especially with ales) known as krausen. For most basic ales, this primary or first stage of fermentation takes about 7 to 10 days. Lagers and more highly alcoholic ales take longer.
I wish I could share the fruity floral pleasant scent of actively fermenting beer with you. Words cannot completely describe it.
You'll just have to make a batch for yourself so you know what I'm talking about.
Once the beer is done actively bubbling and the krausen decreases, primary fermentation is over.
It is now time to transfer to another smaller carboy for some more time, known as secondary fermentation. This siphoning into another container is known as racking. Fill your siphon hose and siphon tube with water, then allow it to drain into the smaller carboy. Try to avoid shaking or moving the primary fermentor too much to avoid stirring up the lees (dead yeast and other sediment at the bottom of the carboy). Your goal is clear, not cloudy beer.
Although secondary fermentation is not an absolute requirement- as most of the alcohol has already been created- I strongly encourage it. Resting for a few more weeks allows the yeast to finish its work and most of the larger particles to settle out. This results in clearer and more fresh tasting beer.
Although it may be cloudy with sediment and barely carbonated, I always sample some of my green beer while I am transferring from carboys between primary and secondary fermentation. I mean"green beer" in the context of being young and un-aged- NOT green beer as in the colored stuff some folks drink on St. Paddy's Day!
I enjoy tasting the changes of the beer as it develops and ages.
The airlocks are replaced filled with water and the carboys are placed in a cool, dark, quiet place for secondary fermentation.
Pictured above in our storage closet are my Irish Red Ale, the Pale Ale (which I just made) and a Barley Wine (about 12% alcohol).
The other enemy of beer (beside oxygen and wild yeast/bacteria) is light. If beer is exposed to light, hydrogen sulfide will form, resulting in a rotten egg or "skunked" beer smell. Beer should always be kept away from light. If the carboys cannot be placed in a closet out of light, then I wrap a towel around them.
Depending on the type of beer, secondary fermentation may take only two or three weeks (most ales), or up to two to four months (some lagers and barley wines).