primary fermentation

[gianfrancs]

I am brewing my first batch of beer. I have been doing wine for some time now and admit that the instructions that come with a beer kit are far less detailed. I started the batch 24 hrs ago and see no action even though fermentation should have begun within 5 10 15 hrs. Also, should the primary fermentation be done sealed with an airlock (no oxygen) or is oxygen necessary for primary fermentation?

 

[Iordz]

Before the yeast is pitched the wort should be aerated. The brewer can shake, splash or use an aquarium pump to dissolve oxygen into the wort. This is essential for proper yeast propagation and complete fermentation. Make sure it's not too hot or cold for the yeast to do their job.
Lag time can be different for all batches, but one should generally see airlock activity within 24 hours, but the activity isn't a sure sign of fermentation. Use your hydrometer to confirm fermentation activity. It can take longer for the yeast to start, but there are many factors. As for the airlock, I would recommend one as this is your first batch, but you can ferment without one, which is what I do.
The best advice I can give you is to relax and let the yeast do its magic.

 

[T-bone]

The airlock will help keep out oxygen, bacteria, and mold. Without it, I'm not sure how you could keep your fermentor from exploding. If you've got one, use it.

Oxygenation is necessary when pitching your yeast, but detrimental at any other time. What temperature was the wort when you pitched your yeast? Too hot, and it could die.

 

[Tankard]

My first batch didn't start fermenting until 36 hours after I pitched the yeast.

The beer turned out delicious. It can take up to 72 hours for fermentation to begin.