How do you monitor the fermentation process?

[animuL]

I'm curious what people do to know when fermentation is complete. I think most commonly I see "after no "burps" of the airlock have occurred in 48 hrs the process is done" but short of sitting there and watching it how do you know?

 

[JonM]

Forget about the bubbles - the only way to know is with consecutive gravity readings, taken a couple days apart. If the specific gravity is stable for those two readings, fermentation is done.

 

[brewbama]

Officially, I should say take a cpl gravity readings a cpl days apart. When they match, it's done.

I wait about three weeks. It usually slows to one blurb an hour or two by then and I declare victory.... unless it's a 6-8 week higher gravity brew - that's when a 3-4 week brew will pass it in the pipeline.

In other words don't worry about it.

 

[flars]

I take a specific gravity reading at 14 days, and then another 3 to 4 days later.

 

[kombat]

If I'm lazy, I just let it ferment 21 days, then proceed. If it's not done after 21 days, then it's infected and it will be obvious. Since I keg, the risk of bottle bombs is a non-issue anyway.

I've started shortening my fermentation cycle in the interest of getting hoppier beers to the tap faster, while they're still fresh. My current process is 5 days of controlled fermentation temperature (63.5° F), followed by a warmup to room temperature (65 - 70°) for a week, then cold crashing, gelatin, etc. and into the keg. I check the gravity once, to calculate ABV, but I never bother with the "consecutive readings, 3 days apart" stuff. If I were bottling, I probably would. Probably.

 

[LLBeanJ]

I usually lift the lid and take a peek inside the fermenter every day just to see how it is progressing. When the krausen begins to clear, which is usually between 3 and 7 days, I know it's just about done. If dry-hopping, this is when the first round goes in. I give it another 3 days and take a gravity reading, which I fully expect to be at FG and it usually is. Around day 14, give or take a couple days, I keg it.

 

[Psylocide]

I hug the carboy each and every day. Tell the beer that it's doing great and that I can't wait to meet it.

I sniff the airlock several times a day... I'm not sure if it's the oxygen deprivation that I'm addicted to or the sweet smell of hops, but it makes me dizzy.

I take a reading around day 10, and another around 14. This go around, I'm going to skip the day 10 reading and just start the cold crash/take FG on day 14 and keg a few days later.

 

[LandoLincoln]

I'm curious what people do to know when fermentation is complete. I think most commonly I see "after no "burps" of the airlock have occurred in 48 hrs the process is done" but short of sitting there and watching it how do you know?

For the most part, I rely on time being the primary factor. I let my beers ferment and most yeasts do their thing within 1-2 weeks and then the krausen falls and the bubbler stops moving. Then I usually wait another four or five days and then check the SG and see if it matches my expected FG and if it does or is within two points of expected, then I keg it up. Since I keg and serve my beers out of kegs, I don't have to worry about bottle bombs so FG is really not that critical.

But if I bottled then I'd wait for the krausen to fall, wait two days, take a reading, then come back three days later and see if the SG was the same as the previous reading.

Some yeast strains don't let that krausen fall very quickly, so this isn't the solution for all yeast strains. I'm very rarely in a hurry to keg any of my beers, though, so wondering if my beer is completely attenuated is not much of a concern to me.

 

[sandyeggoxj]

I watch the blowoff tube. Once it slows down I put on the spunding valve and set the pressure relief to about 2-3psi. Then I wait a few days and take some gravity readings. Once I'm close to my expected fg I raise the temp to 70 and toss in some dry hops for a few days. Then I'll dump the yeast cake and hops and crash it. Add gelatin. Wait. And then warm it back up and add some more dry hops. Then wait 3 more days and crash it again for about a day or two. The off to the keg. When it is cold crashing the last time I pump up the co2 pressure to about 5 or so psi. That way it works on carbing to 1.7 volumes. Put it in the keg into the cold conditioning chamber and pump the co2 up to 35 psi for 24 hrs. Then leave one keg to cold condition and drop the other one into the kegerator and enjoy it fresh.

 

[animuL]

Thanks for the replies. I didn't even think about the SG readings and what I had in mind is WAY more complicated. I was thinking about affixing a sensor to the airlock that detects the bubbles. It would either have a timer that resets every time a bubble is detected or would count the bubbles per hour and output them to a graph.

 

[Jayhem]

I go by clarity of the beer. I use better bottles to ferment so it's easy to see what's going on. I've brewed at least 35 batches so far. I always ferment 21-31 days regardless. When beer is down with active fermentation and the foam (krausen) dies down it still needs 1-2 more weeks to finish and settle out. Once the beer starts clearing up and becoming less cloudy it's a good indication that not only has it reached final gravity, it's also cleaned up and most of the yeast has naturally settled out of suspension. I don't even take final gravity readings on my house beers anymore. I can tell it's ready for packaging based on clarity alone.

When in doubt. Wait 21-28 days before bottling ales.

 

[LandoLincoln]

Thanks for the replies. I didn't even think about the SG readings and what I had in mind is WAY more complicated. I was thinking about affixing a sensor to the airlock that detects the bubbles. It would either have a timer that resets every time a bubble is detected or would count the bubbles per hour and output them to a graph.

BDMA

Bubbles Don't Mean Anything.

 

[1977Brewer]

Bubbles are not an indication of fermentation activity. The only reliable and accurate measure is specific gravity.

That said, I do want to put a nanny cam in my ferm chamber so I can watch the most active stage. Like sea monkeys, but they're making me beer!

 

[LLBeanJ]

That said, I do want to put a nanny cam in my ferm chamber so I can watch the most active stage. Like sea monkeys, but they're making me beer!

Beer monkeys!

 

[Psylocide]

Bubbles are not an indication of fermentation activity. The only reliable and accurate measure is specific gravity.

That said, I do want to put a nanny cam in my ferm chamber so I can watch the most active stage. Like sea monkeys, but they're making me beer!

I've seen time-lapse videos on vigorous ferments, looks pretty cool.

 

[1977Brewer]

I've seen time-lapse videos on vigorous ferments, looks pretty cool.

I think Anchor has one up of their open chamber. I'd love to see one of a carboy.

 

[Psylocide]

I think Anchor has one up of their open chamber. I'd love to see one of a carboy.

Google it, there are a few. I liked the second one better, crazy stuff happening with the trub on that one.

[ame]https://www.youtube.com/watch?v=hFf9RVxSUFk[/ame]

[ame]https://www.youtube.com/watch?v=xm33934qM4E[/ame]

 

[1977Brewer]

Google it, there are a few. I liked the second one better, crazy stuff happening with the trub on that one.

https://www.youtube.com/watch?v=hFf9RVxSUFk

https://www.youtube.com/watch?v=xm33934qM4E

Beer monkeys!

 

[kpr121]

Bubbles are not an indication of fermentation activity. The only reliable and accurate measure is specific gravity.



That said, I do want to put a nanny cam in my ferm chamber so I can watch the most active stage. Like sea monkeys, but they're making me beer!

Set this up yesterday... Oldish not used otherwise ip camera that I set up for s&g. Doesn't connect to my network inside the freezer, but I can hear the bubbles blowing in blowoff from the dipa I brewed yesterday.

I know bdma but it's cool to me!

On the real question, I don't really watch fermentation. Just pitch a healthy amount of yeast, ferment at the right temps, and let time take care of things.

View attachment ImageUploadedByHome Brew1424124566.195214.jpg

 

[animuL]

The time lapse idea is cool. I can do right at 1 week with my GoPro so I might have to try that next time for fun but it sounds like my mistake has been following the bubbles and not the sg. I hope I didn't screw up my latest batch because it sat in the primary for about 4 days then went into the carboy for 12 days, so 16 days total and I wasn't seeing any bubbles so I went ahead and bottled it. OG was 1.064, and was 1.030 when it went into the secondary and somehow 1.030 as well after going into the bottling bucket. I did however get the 1.030 reading with the primary in the bottling bucket so maybe that caused it to read higher than reality. But 4.5% abv seems low, its brewers best oatmeal stout.

 

[philosofool]

Once the bubbles have stopped, i press the lid of the fermeneter to let a few bubbles through to drop the bobber in the airlock. I come back fifteen minutes later. If it's still dropped, primary fermentation is over. I usually condition my beers in primary for a variable number of days, depending on such things as yeast strain and my time for messing around with beer.

People say you can't use the bubbles and I don't advise new brewers to use that method. However, experienced brewers have a very good feel for fermentation. If it's not going right, I can usually tell and my hydrometer will back me up, but when it's going right, I just look to the air lock. It never fails me.

 

[Natdavis777]

I watch the beer in the chamber and when the krausen starts to fall, I warm up the temp (some may say a D rest isnt necessary, but rather be safe than sorry after having my first beer come out a butter bomb). Usually after 14 days most is done. Ill check my gravity and then again a few days later...sometimes. If the beers rides for 3-4 weeks, I dont bother checking and proceed to kegging.

The only time this has nipped me in the butt is on two lagers, which I severely underpitched. Every beer since has been properly aerated/pitched and havent had any issues