Pitching the Yeast
If the Dry Yeast Starter is not foaming or churning, use the backup yeast. Repeat the re-hydration procedure and then pitch the Yeast Starter into the beer, making sure to add it all. Put the lid in place and seal it. Do not put the airlock in quite yet. Place a piece of clean Saran Wrap over the hole in the lid and cover it with your hand.
With the fermenter tightly sealed, pick it up, sit in a chair, put the fermenter on your knees and shake it several minutes to churn it up. This mixes the yeast into the wort and provides more dissolved oxygen that the yeast need to grow. Wipe off any wort around the hole with a paper towel that is wet with bleach water and place the sanitized airlock and rubber stopper in the lid. The airlock should be filled to the line with the bleach water solution.
Active fermentation should start within 12 hours. It can be longer for liquid yeasts because of lower cell counts, about 24 hours.
Put the fermenter in a protected area like the bathtub. If foam escapes it will run down the drain and is easy to clean. The temperature here is usually about the most stable in the house. Animals and small children are fascinated by the smell and noises from the airlock, so keep them away.
The airlock should be bubbling in twelve hours. Maintain a consistent temperature if possible. Fluctuating temperature strains the yeast and could impair fermentation. On the other hand, if the temperature drops overnight and the bubbling stops, simply move it to a warmer room and it should pick up again. The yeast does not die, it merely goes dormant. It should not be heated too quickly as this can thermally shock the yeast. In summary, if the temperature deviates too much or goes above 80F, the fermentation can be affected, which then affects the flavor. If it goes too low, the ale yeast will go into hibernation.
The fermentation process can be very vigorous or slow; either is fine. The secret is in providing enough active yeast. Fermentation time is a sum of several variables with the most significant probably being temperature. It is very common for an ale with an active ferment to be done in a short time. It could last a few days, a week, maybe longer. Any of the above is acceptable. Three days at 70F may be regarded as typical for the simple ale being described here.
If the fermentation is so vigorous that the foam pops the airlock out of the lid, just rinse it out with bleach water and wipe off the lid before replacing it. Contamination is not a big problem at this point. With so much coming out of the fermenter, not much gets in. Once the bubbling slows down however, do not open the lid to peek. The beer is still susceptible to infections, particularly anaerobic ones like Lacto Bacillus, found in your mouth. It will do just fine if left alone for a minimum of two weeks.
The fermentation of malt sugars into beer is a complicated biochemical process. It is more than just attenuation, which can be regarded as the primary activity. Total fermentation is better defined as two phases, the Primary or Attenuative phase and a Secondary or Conditioning phase. The yeast do not end Phase 1 before beginning Phase 2, the processes occur in parallel, but the conditioning processes occur more slowly. This is why beer (and wine) improves with age. Tasting the beer at bottling time will show rough edges that will disappear after a few weeks in the bottle. Because the conditioning process is a function of the yeast, it follows that the greater yeast mass in the fermenter is more effective at conditioning the beer than the smaller amount of suspended yeast in the bottle. Leaving the beer in the fermenter for a total of two or even three weeks will go a long way to improving the final beer. This will also allow time for more sediment to settle out before bottling, resulting in a clearer beer.