Beginner fermentation question

Yeast & Fermentation
1

My second batch of beer (NB petite saison kit w/ wyeast 3711) has been in primary for 13 days. I just took the gravity reading, and it seems to have fully attenuated (OG= 1.039; FG= 1.005). I waited this long to take the reading, because I’m still getting bubbles through the airlock. In fact, they aren’t much less frequent than they were after the first week.

So my question(s): 1. how reliable a guide is “wait until airlock activity stops”, especially if I want to avoid opening up the carboy regularly?; 2. what am I to make of the long fermentation time? Temperature (taken twice a day) was between 69 and 70 from day one until now; 3. I assume I should just bottle now?

One more point that I’m curious about: my first brew (Hefe) had a very vigorous first few days, requiring a blow-off tube. This brew never did. When I looked in during the first week, there was vigorous swirling. Now, there doesn’t seem to be much movement, but there are very little bubbles coming up from the bottom of the carboy. What are they?

Apologies for all of the questions – just very curious what more experienced brewers suggest. Thanks!

2

The amount of yeast activity is going to be related to the starting gravities. In this case it was pretty low so you might not have seen as much activity. Yeast strains also play a role, some are much more active than others too.

For a beer with that low of a gravity, you’re probably in good shape to bottle it. Also good job on making sure you’re at your final gravity. The airlock activity could be the beer degassing as the CO2 comes out over time.

3

That isn’t a long fermentation time for the average homebrewer. Two weeks is the minimum I would recommend for any new brewer. To get faster fermentations, you need to know how to manipulate your yeast via pitching rates, yeast health, and temperature control.