So I have attempted to take FG readings without a thief and find that gravity readings don't change in a measurable amount on a daily basis and am curious what the "feeling" is for when a brew is ready for the secondary. I have heard; "as soon as the krausen falls and not a minute later", "when gravity readings are the same two days in a row" and a couple "ferment for x days" with no specification of activity status after those days.
My experience is that each batch has much different activity. One ferments for 4 days and krausen falls, another ferments for 10 days and is still bubbling.
So is there a general rule of thumb in terms of bubbles per minute?
My current batch, at 13 days fermentation, is bubbling once every 1.5 minutes. Should I really wait for no sign of activity. I have heard that the flavor can be negatively affected by sitting on a bunch of dead yeast cells. These theories conflict one another - wait for no activity but hang out and party with the dead yeast???
For average ales I'll wait 7-10 days or when I get less than 1 bubble per minute, whichever is last. For bigger beers, I'll wait 2-3 weeks or when I get less than 1 bubble per minute, whichever is last.
Hope that helps,
On Tap -
3 year old Oak Aged Bourbon Porter
Irish Red Rye
Russian Imperial Stout
Mirror Pond Clone dry hopped with Citra
Mirror Pond Clone dry hopped with Centennial
Primary - Nada
From man's sweat and God's love, beer came into the world. -- Saint Arnoldus
The yeast isn't dead just yet...just dormant feeding off the reserve tanks. when those run dry things get ugly and your beer turnes into a mass grave for cannibilistic yeast. This takes several weeks or months (depending on a host of factors) to produce any real discernable flavor change.
Bubbling once per 90 seconds, you say?? Rack to secondary. You can check the gravity when racking to the secondary, but odds are it's pretty much done. I take half a pint or so to taste as well. Mostly just as an excuse to drink it!
Every little thing is gonna be alright.
Airlock activity is not an accurate indicator of whether primary fermentation is compete. If your FG reading is in the neighborhood of 75% of your OG reading then you are good to rack it to the secondary. The gravity may drop another couple of points in the secondary, but for all intents and purposes, 75% attenuation is about all you can expect from most ale yeast. Some will attenuate higher and some lower, but 75% is a good rule of thumb.