In your primary fermentation vessel the majority of the simple sugars are converted by yeast into alchohol. A great deal of carbon dioxide is produced during primary fermentation and if you use a glass vessel it will look like the solution is almost alive the fermentation is so active. It should be noted that because of the carbon dioxide produced a great deal of pressure can be produced. If you do not use an appropriate airlock your fermentation vessel can explode which is not only very messy but dangerous if you use glass.
After your primary fermentation you more the beer into your secondary fermentation vessel for none other than secondary fermentation!
Last Updated: July 12th, 2006