The science of bubbling air locks

[Pyg]

I know stooopid title, but a few homebrews in me and I couldn't come up with anything else.

Here is the deal. The previous 2 brewa were done in February and March. I kept the Bucket in the living room (66f) for 3 weeks and it bubbles through the air lock consistently the entire time.

I currently have an IPa in the basement in a igloo cube, with a heat pad on it. It is currently at 68F and after 4 days has slowed bubbling.
It bubbles occasionally but nothing like either brew before.
I know the batches are different and conditions, but is it possible for that quick of a ferment?
I usually don't check for FG until after 2 weeks, so I have another week.

Any ideas?
It should I just go have another beer?

 

[brew_ny]

well having another beer is always a good idea

a bit more info would help like OG, what yeast you are using, the recipe etc.

all the best

S_M

 

[watermelon83]

In my experiences, ale strains ferment more quickly in higher temps. That being said, the only way to know if you're yeast are done with the fun is to take gravity readings over a couple days.

 

[Pyg]

well having another beer is always a good idea

a bit more info would help like OG, what yeast you are using, the recipe etc.

all the best

S_M

In my experiences, ale strains ferment more quickly in higher temps. That being said, the only way to know if you're yeast are done with the fun is to take gravity readings over a couple days.

I guess having 3 homebrews (2 cream ale, 1 pale Ale) mixed with 4 or 5 whiskeys left me rambling, sorry about that.

Recipe is as follows:
6.6# light LME
1# corn sugar
8 oz Carmel 80L (steep)
8 oz victory (steep)
4 oz carpils (steep)
1 oz Columbus (60 mins)
1 oz citra (15)
1 oz Amarillo (10)
1 oz Amarillo (5)
1.5 oz cascade (dry hop)
Dan star American west coast yeast.
My 5 year old's explination as to why the the bucket is no longer bubbling was "because you are upstairs and can not hear it in the basement".
Sound advice.
However as previously stated my last 2 batches made in my living room bubbled consistently almost every few minutes.
My brew in the basement at 68F is no longer bubbling.
I am going to take an FG reading tonight and if need be move the bucket some place warmer. However the up stairs is way to warm as we are due for 80F all weekend and most of next week.

 

[unionrdr]

Well, if you rehydrate dry yeast, as I do, How soon it starts visibly fermenting &/or how quick it finished depends on some other factors. Was the rehydrate at high krausen when you stirred it up & pitched it? Was the rehydrate within 10 degrees of current wort temp? These two things can seriously shorten lag time & ferment out quicker, in my experience.

 

[BlueHouseBrewhaus]

The yeast have minds of their own. I've had some brews reach FG in 2 or 3 days. Others, particularly Belgians, have taken as long as 4 weeks. How long does it take yeast to ferment is one of those Zen koans like what is the sound of one hand clapping So sit back, grab a beer and say "Ommmmm". In other words, RDWH-yada-yada-yada.

 

[unionrdr]

Yeah, that's about it. I've had rehydrated S-04 rip through an ale & start settling out clear in 10 days before. Other times, about two weeks...maybe three. US-05 or WL029 up to 3 1/2 weeks, bubbling steadily. All the conditions have to be right for the yeast to finish quickly. But humans & yeasties being what they are, things aren't the exact same way every time.

 

[Pyg]

Well, if you rehydrate dry yeast, as I do, How soon it starts visibly fermenting &/or how quick it finished depends on some other factors. Was the rehydrate at high krausen when you stirred it up & pitched it? Was the rehydrate within 10 degrees of current wort temp? These two things can seriously shorten lag time & ferment out quicker, in my experience.

I don't re-hydrate, I toss the yeast on top of the wort, shut the lid and walk away.
The wort was about 76F when I started the process.
Since my bucket was in the cold basement I placed it in my Igloo Cube, , added a heat pad & covered the top in blanket to keep the heat in.
The next day the temp was up to 78, so I took all the blankets off and let it air out and it got down to 68F.

I guess my question is why was it the last few batch I had, which was done in 2 weeks, continued bubbling for the 3rd (I do 3 week primary). Possibly degassing in a warm room?
I know there is no way to get a definite answer without checking FG and I can not do that from work.

 

[unionrdr]

Probably just off-gassing. Dry yeast pitched as is can take longer to start & finish up, as you can lose up to 50% of the cells allowing them to rehydrate in the wort, rather than warm water.

 

[azazel1024]

If it was a 78F, even even just for a few hours while the yeast was active, that can finish things up really fast. I say this without actually knowing with YEAST, but a lot of time, chemical reactions double per 10F increase in temperature. I assume yeast isn't quite at that level, but the higher the temperature, the faster yeast will tend to metabolize as well as divide.

So if it got up to 78F, even if it cooled off within half a day or so, odds are good it tore through the sugars in the wort a lot faster than if just fermented at 68F the entire time.

Most West Coast ale yeasts if you ferment in the 68F range can hit 80% of final gravity within about 48hrs after active fermentation starts (IE krausen). At least if you are pitching roughly the right cell count, which you probably did.

Depends a lot on the strain, temperatures, ingredients, gravity and the beer goods whimsy.

I've had 1.040-1.050G ales pretty much finish up in about 72hrs, especially with English ale yeasts fermented at 68F. I've had S05 do roughly the same. Dropping the temp on S05 to 62F seems to stretch it out nearly double with Krausen lasting 4-5 days and the airlock bubbling slowly for another 3-5 days.

My RIS is still occasionally bubbling, though that might be from outgasing and that use S05. Krausened for about 5 days with nice active fermentation for about 8 more days. This was at 62F and then ramped to 70F at around day 10 for a couple of days and then placed on some foamboard on my basement floor (to keep it at 66F. Otherwise straight on my concrete slab it'll drop to 62F, it was actually temp controlled in my fermentation chamber for the first 10 days, then it was upped to 70F and then taken out completely after that).

Belgian yeasts, in my experience, are very, very slowly if the temperature is much below 68F (they also seem to be very sulphury below 68F. A lot of the strains seem to like 70-72F). My Belgian Single that was only 1.052OG with a fair amount of simple sugars (12oz of table sugar, plus mashed at 148F, it finished out at 1.008FG) fermented at 66F (yes, I should have put a heater in my fermentation chamber and cranked it to 72F probably) took about 3 weeks to finally stop bubbling at a rate slower than 1 per minute. Took another 2 weeks for the sulphur to finally die down enough to bottle (opps).

 

[kh54s10]

My guess is that the cooler ones fermented slowly, The one at 78 degrees, which is TOO warm, chewed through the sugars quickly.

As you brew more you will be able to ignore the bubbles in the airlock. They really ONLY mean that co2 is coming out of the fermenter.

I have had some that were finished and still bubbled. co2 coming out of solution. This can be from temperature change or atmospheric pressure change.

Let the beer ferment long enough, check the gravity, bottle and ignore the airlock.

 

[Pyg]

If the batch hits the FG in a matter of a few days, does this shorten the usual 3 week primary?

Or would you leave it to sit and clear for 3 weeks?

I tend to do primary for 3 weeks, but the last 2 days is a cold crash

 

[unionrdr]

Well, on that beer with rehydrated S-04, it fermented out & was quite clear in ten days flat. I gave it a total of 14 days to finish clearing & bottled it. So as soon as it's done fermenting & settled out clear or slightly misty, bottle it.

 

[kh54s10]

If the batch hits the FG in a matter of a few days, does this shorten the usual 3 week primary?

Or would you leave it to sit and clear for 3 weeks?

I tend to do primary for 3 weeks, but the last 2 days is a cold crash

There is really no need to go by a set schedule. Many get to fg, wait as few as a day or so, or until the beer is clear then bottle.

I used to go 3 weeks as a standard. I now go 2 weeks or as much as a month or so. It just depends upon how lazy I get. I don't take gravity readings to try to hit minimum time. When it is a month or more it is usually that I will keg it tomorrow, which turns into tomorrow, which turns into tomorrow.........

 

[hunter_le five]

Four days is not an unreasonable ferment time. Most of mine are finished by day 5 or 6 (lagers being an exception).

More importantly, ignore the airlock and use your hydrometer to determine when it's finished.

If the batch hits the FG in a matter of a few days, does this shorten the usual 3 week primary?

Or would you leave it to sit and clear for 3 weeks?

I tend to do primary for 3 weeks, but the last 2 days is a cold crash

I usually let me beer continue to sit in the primary until it clears, regardless of when it reached FG.

 

[unionrdr]

In my experience, it 'll hit FG before the up/down swirling action ceases & it starts to settle out. Hence my typical answer.

 

[MattyIce]

Trust the hydrometer readings. It is fun to watch the airlock, but it does not tell the whole story.

And bless your wife for letting you keep fermentors in the living room.