Could my fermentation be almost complete after 24 hours?

[Microphobik]

Hi, I'm currently brewing a pretty standard 5 gallon all grain chocolate milk stout (chocolate has not been added yet). In addition to the usual malts its got about a half a lb of roasted barley, half a lb of oats, and 12 oz lactose. I used A pack of dry Windsor British style yeast (no rehydration or starter) and a half tsp of wine yeast nutrient (about one sixth of what I would have used for wine). My efficiency was better than expected and the projected ABV is 6.7%.

Here's the thing... After only 3 hours I had a head of foam so big it blew the airlock. I woke up n the morning (about 7 hours after pitching) and it was bubbling twice per second and the fermentation was explosive. But Now, after only 24 hours its already started to slow down. It's only bubbling once every 5 seconds. There is still plenty of activity bu the trub is starting to settle.

Is it possible my yeast just tore threw this that fast or could I be heading for a stuck fermentation. I've had fast ferments before but nothing this fast. Normally I'm not slowing down for at least 3 days or so. Just wondering if this is more normal than I realized or a sign of trouble?

Thanks for any advice.

 

[Microphobik]

Okay , so after posting that I read a bunch and it suddenly dawned on me that I may have fermented to warm. I am at 71 now but didn't record what it was the first few hours and suddenly worried that I was way too high. So I broke down and took a reading. It is definitely not done but it has dropped from 1.078 (that's with lactose remember) to 1.048. Still pretty fast for less than 24 hours. But the best news was that it's sating great. No noticeable esters or banana-ish flavors at all. Not sure if the remaining sweetness would hide those though???

Anyway, so now my concern is the dramatic slow down in ferment after such a short time. Could I be heading for a stuck ferment or is that unlikely given the vigorous activity right out of the gate? Never had a stuck ferment so I don't know the ropes.

Anything I should do preemptively or does this sound normal enough?

 

[JonM]

Nope, just let it ride for a couple weeks. Check the gravity in maybe three weeks. Just leave it be in the meantime (and maybe get the temp down a couple more degrees.)

 

[Microphobik]

Hmmm, woke up this morning and the bubbling is down to just one little blip every 60 seconds and there is little noticeable activity. There is still a lot of sugar in there. Hoping this isn't a stuck fermentation, or a situation where the yeast strain can't handle the high gravity. I guess we'll see.

 

[sweetcell]

my suspicion is that you are headed for a stuck ferment because you under-pitched.

mrmalty says that 5 gals of 1.078 requires 1.3 packs of dry yeast. you said that you didn't rehydrate. according to some folks (like Jamil Z, who i very much trust when it comes to matters of yeast), you can kill up to half of the cells by pitching directly on to wort, especially high gravity wort. assuming this is the case, you're already at less than 50% of the recommended yeast dosage. throw in a few other problems - maybe the yeast was stored in a hot warehouse before getting to you, the wort wasn't sufficiently aerated (not a prob with a proper pitch of dry yeast, but that's not our case here), and things start to look dicey.

can you get your hands on some more yeast? i'd wait another day or two and take a reading. if you're not much below 1.048 (your last reading), i'd consider making a starter (even with the dry yeast, to get them active) and pitching at high krausen. windsor yeast is relatively fast and is a good flocculator... waiting 2+ weeks to see what happens is another approach but i wouldn't trust Windsor to remain in suspension all that time (on top of the fact that there are less cells than required).

 

[tre9er]

I would consider adding more yeast, too. Then just leave it alone for 3 weeks. This is a big, complex beer. Forget about it until it's done it's thing.

 

[Microphobik]

Thanks sweetcell, that's sounding right to me. My feeling is that this activity is dropping so quickly that something is wrong. I saw so man people saying they disregarded the rehydrating step that I thought I'd just be lazy as well. I can definitely get some more yeast. So I'll give that a try. Best to try a different strain or stick with Windsor?

Just so I understand how this works for the future... I would have assumed that under pitching meant that it wold take a lot of time to get the yeast going and if they couldn't get going there could be problems. But I assumed when I saw 6 inches of foam popping the airlock out that I everything had multiplied nicely and I was in good shape in that regard. What am I not understanding?

Thanks again.

 

[tre9er]

Thanks sweetcell, that's sounding right to me. My feeling is that this activity is dropping so quickly that something is wrong. I saw so man people saying they disregarded the rehydrating step that I thought I'd just be lazy as well. I can definitely get some more yeast. So I'll give that a try. Best to try a different strain or stick with Windsor?

Just so I understand how this works for the future... I would have assumed that under pitching meant that it wold take a lot of time to get the yeast going and if they couldn't get going there could be problems. But I assumed when I saw 6 inches of foam popping the airlock out that I everything had multiplied nicely and I was in good shape in that regard. What am I not understanding?

Thanks again.

Sugar is readily eaten by yeast, and you have a lot of it. It will go crazy at first but may start to taper off. Adding more yeast increases the chances you get down to a good FG. Your profile is probably mostly established with the yeast you have. If you were to pitch more in the next few days I'd go with Nottinham probably, or Pacman.

 

[Microphobik]

Thanks, one other thing I'm unclear on... Lets say things continue along okay but the beer finishes pretty sweet, as it should anyway with Windsor... How does this effect priming? If the yeast are puckered out because of the alcohol level, how are they going to suddenly then find the energy to eat my priming sugar and carbonate for me?

 

[sweetcell]

I saw so man people saying they disregarded the rehydrating step that I thought I'd just be lazy as well.

dry packs contain approx 220 B cells, based on what i've read. you can be lazy and not rehydrate because even half that number is often enough for a small'ish beer in the 1.040 range. unfortunately yours is twice that.

Best to try a different strain or stick with Windsor?

windsor isn't a very attenuating yeast, it leaves behind quite a bit of sugar. unless you like your stouts really, really chewy i would consider using something a little more attenuative. you've got a good amount of lactose in your recipe so that will add a lot of sweetness. i'd go with something a little more attenuative like US-05.

Just so I understand how this works for the future... I would have assumed that under pitching meant that it wold take a lot of time to get the yeast going and if they couldn't get going there could be problems. But I assumed when I saw 6 inches of foam popping the airlock out that I everything had multiplied nicely and I was in good shape in that regard. What am I not understanding?

your initial pitch of yeast contains a certain amount of cell material. every time a cell splits, it has to give half of everything it has to each new cell. so the first division yields cells with 50% of the original cell's resources. next generation gets 25% each, then 12.5% each... eventually there won't be enough left to create new viable cells, the reproduction has hit its limit (to be fair the cells can pick up some resources along the way...)

once the cells can't reproduce anymore, they'll get down to munching on the sugars. the cells will be weak at this point. they'll gorge themselves on sugars and "fatten up", but some won't be able to handle the presence of alcohol because of their weakened state. so what was a small population to start with gets even smaller... and eventually the whole thing crashes to a halt before all the sugars are consumed. you've got a stuck fermentation. so it's not just a matter of time, it's also how healthy a population you start with.

in the case of a proper pitch (i.e. sufficient number of cell), reproduction will stop once the yeast have reached a sufficient population for the amount of food available - and this will be before they run out of resources for reproduction, so the resulting cells are healthier and less stressed. they will be able to handle the alcohol and other by-products (including consuming their own waste at the end of fermentation).

over-pitching can lead to taste issues: a lot of flavors are created during reproduction. if you pitch too much yeast, they don't need to reproduce, so those tasty esters and phenols aren't created.

 

[Microphobik]

That's awesome, thanks. If the yeast has hit it's limits and can no longer survive how does it then work with priming? It would seem to me that if the yeast are tuckered out and no longer consuming sugar then all adding priming sugar would do is make my beer sweeter. Or is it different because it's corn sugar? I just want to make sure I don't get a flat beer here.

I do have some US-05 on hand. Someone else suggested Nottingham. I wanted this to be sort of a thick beer with a lot of mouth feel, and I didn't want it too dry, so I thought I'd try Windsor. But mostly I just want a drinkable beer

Will the US-05 thin it out a lot or do you think the lactose and a mash temp of about 55 will maintain that thick mouth feel?

Thanks again. Great info.

 

[sweetcell]

If the yeast has hit it's limits and can no longer survive how does it then work with priming? It would seem to me that if the yeast are tuckered out and no longer consuming sugar then all adding priming sugar would do is make my beer sweeter.

the "hit its limits and can no longer survive" scenario occurs only when the yeast is under-pitched. in the case of a healthy fermentation (i.e. a proper pitch), the yeast stop fermenting only because they have run out of sugars - they have consumed them all. lacking an energy source to live off of, they go dormant. adding the priming sugar = new source of energy = they wake up and get back to work, assuming they have the right conditions. this is one reason why folks repeat the mantra "3 weeks at 70*F to carbonate" - because those are the right conditions to wake up that dormant yeast.

if you have a stuck ferment because you under-pitched, then yes the priming sugar likely won't be consumed.

I do have some US-05 on hand. Someone else suggested Nottingham. I wanted this to be sort of a thick beer with a lot of mouth feel, and I didn't want it too dry, so I thought I'd try Windsor. But mostly I just want a drinkable beer

Will the US-05 thin it out a lot or do you think the lactose and a mash temp of about 55 will maintain that thick mouth feel?

i completely understand your desire to have a nice, thick, chewy stout. but more often than not, the challenge is to get the beer to go low enough (i.e. the beer ends up too thick and too sweet). between the lactose and the 155*F mash, I believe you'll have plenty of body. it's better to be on the thinner & drier side (aka very drinkable) than on the sirupy side.

 

[tre9er]

Pitch new yeast. You have lactose in there. It won't dry out because yeast can only eat what's there. Between the lactose and dextrins, you'll have mouthfeel. You need healthy yeast pop for carbing anyway. If you're really paranoid you can add yeast to the bottling process, which is really common. They'll only eat what's there, so no worries of bottle bombs if the beer fully attenuated prior to bottling.

 

[Microphobik]

Okay, so after 3 days of waiting and almost no visible activity I checked the gravity and got a reading of 1.044. That's only a drop from 1.048. And remember, I took the gravity reading while there was still SOME activity so those couple of points could have been shaved off at the tail end as apposed to spread out over 3 days.

So I went and pitched some US-05 dry and got some pretty quick activity. But then after about 10 hours or so all the activity has stopped again. What could be wrong here?

Only things I can think of...

1. We live in a fire place heated home and the nights are fairly cold. The average temp on the stick-on thermometer has been about 64. That's a drop from 71 when it was bobbling away. It's relatively constant in the day but those nights do get a bit chilly. But normally I found the self generated heat from the ferment to be enough to keep it up through the nights.

2. I shook the crap out of it in the carboy and let it splash as I filled it up but could insufficient oxygen be the cause? If so, what should I do? I don't have an air stone but I could certainly give it a regular stir a couple times a day. Just don't want to risk the nasty effects of too much oxidization.

3. Could I have done something wrong during the mash and not converted enough of the starches into sugars? It seemed to be pretty standard. I kept it right around 155, it would drop a touch and I would goose the heat a bit to bring it back. But I didn't have any real problems there. But this was a BIAB with a standard stainless steel dip thermometer (not sure what you call those). I suppose it's possible it was a good deal hotter down at the bottom (even though I did stir it before taking readings. Could that be a problem?

4. I brought my water up to the mid to high sixties before adding the grain, anticipating a 10 degree drop or so. Could it have been too hot and killed some of the necessary enzymes? Or is that not likely given the fact that it fermented so well for the first 24 hours?

Any ideas? The samples all taste great, all be them a bit too sweet. I'd hate to lose this beer. The only thought I have is to give it a stir and bring it a bit closer to the fire place to see if I can't give it a jolt. Any ideas?

 

[Microphobik]

Just wanted to give this a bump. Any additional thoughts on this?

 

[sweetcell]

how chilly is "nights do get a bit chilly"? that could be causing the yeast to go dormant, if it gets cold enough.

 

[Microphobik]

Unfortunately I don't have a thermometer in the house but the stick on thermometer on the carboy was saying 18 Celsius which is about 65 F if I remember right. The temp being my only idea left I tried giving it a gentle stir and then turning the heater on it until I got it up to 22 Celsius, which is 71 F and it's definitely started moving again. It's not going nuts but I'm seeing a bubble every 20 seconds or so and there is a slow and steady stream of bubbles coming up through the beer and plenty of those small explosions coming up from the sediment at the bottom. And it's been holding like that for 24 hours or more now. So I plan to give it a week or wait until the bubbles stop and check the gravity to see what's going on. But fingers crossed, I may have got it.

Thanks for the tips and help.