slow fermentation????

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Feb 17, 2013
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Hello again, I brewed my second beer on Saturday, an Irish Red, with liquid yeast from white labs 004, with a 3 cup water, 3/4 cup dme starter which I made on Wedensday night. 5 1/2 gal boil. the fermentation started off slowly at about 20 hrs, 1 bubble per second, and since it seems to be slowing down, only 1 bubble about every 3 seconds.:confused::confused::confused: My first batch was an Oktoberfest with an ale yeast starter and that almost exploded the airlock off the carboy!!!!!!! the temp on the carboy is 70 deg, was just wondering if this seems normal for this type of red ale??? My only other comparison was the oktoberfest which went haywire and this just seems to be puttering along!! should I raise the temp of the carboy???(do those heat belts or wraps work good???) Just a little concerned!!
Also with this red ale, would it be ok to leave it in the first carboy for 2 weeks and then bottle???????? or would I benifit from a second ferm in another carboy for 2 more weeks????
Thanks again from "still a newby!!!"
Jan 17, 2012
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Hey B.B.,
If you do a little looking around for similar threads, you'll see similar answers. Revvy is particularly eloquent: Airlock activity does not equal fermentation activity. It is simply a vent for excess gasses.
I know that there is some comfort in seeing that thing a-chugging along, but it really doesn't mean anything. So, if you don't have one, get yourself a hydrometer. But don't even bother to look for a week or two. Yeast know all.
70* is plenty high, in fact a little too high. Try to get it down to mid-60s and leave it alone.
I would left her ferment out and cleanup byproducts for a total of 3-4 weeks before bottling. Whether all in primary, or some of it in secondary is up to you. You will see plenty of opinions on both sides on this and other forums.


Post Hoc Ergo Propter Hoc
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Dec 11, 2007
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"Detroitish" Michigan
Counting bubbles does not equate to anything usable in fermentation. It's not like "x bubbles/minute= y gravity points." It just means that co2 is being released....but it could also NOT be bubbling, and still fermenting away.

An airlock is a VENT, a VALVE for EXCESS CO2. It's not a magic fermentation gauge. When the majority of sugars are eaten in the initial burst of fermentation, lots of co2 is released. As it slows down, bubbling ceases or stops altogether because there's not as much EXCESS Co2 being released.

But that doesn't mean fermentation is over, just that it's slowed down.

Fermentation is not always dynamic...just because you don't SEE anything happening doesn't mean that the yeast aren't happily chewing away at whatever fermentables are in there....the only way to know comes from gravity readings, and nothing else.

Activity, action, bubbles, even krausen can be affected by the envoironment just as much as it being caused by the going by that is NOT reliable.

If you want to know what's going on with your beer, then take a gravity reading. The only way to truly know what is going on in your fermenter is with your hydrometer. Like I said here in my blog, which I encourage you to read, Think evaluation before action you sure as HELL wouldn't want a doctor to start cutting on you unless he used the proper diagnostic instuments like x-rays first, right? You wouldn't want him to just take a look in your eyes briefly and say "I'm cutting into your chest first thing in the morning." You would want them to use the right diagnostic tools before the slice and dice, right? You'd cry malpractice, I would hope, if they didn't say they were sending you for an MRI and other things before going in....

Relax, leave your beer alone and let it do it's thing for a couple more weeks, and most importantly, IGNORE what your airlock does or doesn't do.

In fact you might find this discussion on the superfluousness of airlocks something that will help you get a handle on this. It was started by a newer brewing who just grasped this concept.


Homebrewer, author & air gun collector
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Feb 19, 2011
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It could be fermenting slower this time if your wort starting temp was real low,& the starter temp was higher by more than 10 degrees. The yeast will be really slughis till the wort temp comes up to within it's normal range.