I have just brewed my 4th batch. so far 3 batches of 5 gallons of wort were placed in a 6 gallon plastic fermenter with little headspace. my 4th batch however is small (only 3.5 gallons) and it is sitting with 2.5 gallons of headspace in the fermenter. I can see foam and activity when I look at the side of it. but even after 2days, there is no bubbling. I guess the co2 is filling up the extra space. my question is: will that extra space affect the beer?