sg constant, but steady airlock activity

[rcrabb22]

I have read numerous posts about airlock activity not an accurate indicator of fermentation activity. Here comes the "BUT"......

Northern Brewer Irish Draught kit
6 gal Carboy, 3 gal boil, 5 gal total batch
Used dry yeast, Danstar Windsor
OG on box = 1.045 mine was 1.046
Temperature in the basement has been a constant 70F,

Strong fermentation, good krausen head 8 hours after pitching yeast, dropped after 24 hours. BTW - All three of my batches to date have had similar fermentation activity behavior. Northern Brewer Nut Brown and this were Winsdor, the other (NB Irish Red kit) was Nottingham.

2 weeks in primary, SG has been 1.017 for 1 week over 3 readings *but* still seeing steady bubble from airlock, 1 every 45 seconds or so. See a little bubble come to surface of beer every now and then if you watch close. 10 or 12 quarter sized groups of bubbles (looks to be single layer) on surface.

I was planning 2 more weeks in primary, then bottle.

I'm just curious what is the yeast doing if the SG is staying constant?

Thanks

 

[ExpertBrewers]

Small amounts of residual CO2 could be coming out of solution.

 

[Rezilynt]

The yeast is cleaning up. The bubbles you are seeing are from CO2 escaping. The hydrometer really is the way to measure when fermentation is done.
Here is a good link explaining what the yeast cycle is -

http://www.beer-brewing.com/apex/brewers_yeast/brewers_yeast_cycle.htm

 

[rcrabb22]

Thanks for the advice and link. It seems as is well for now.