Routeinely Stuck Fermentations

Hey guys, first time poster here! Hoping you can solve my basic conundrum.

I've been brewing for about a year, entirely from brewer's best partial-boil extract kits. Until about 3 batches ago, I've never bothered to check/record OG/FG readings; I tried on our first batch and didn't understand it, so I never bothered. A few batches ago I started recording my readings, and I'm finding that the FG isn't usually getting as low as I'd expect. On my latest batch, I brewed from extracts but without using a kit; the OG was 1.066, which is a bit higher than I usually have been getting with the kit beers.

What I've noticed after taking readings is that I'm usually getting from around 1.050 to around 1.020; about a 30 point drop. Not terrible, but not great. On my latest beer, which had a higher OG, it went down from 1.066 to 1.042. I'm only 2 weeks into Primary, but I measured it after 1 week just to be certain, and haven't found a change.

What I'm thinking is that something in my process is limiting my fermentation to about 20-30 points, then I'm getting stuck on something. From what I've read, the common causes are lack of nutrients, temperature, or lack of oxygen. But I've also read that extract beers usually have enough nutrients, my temperature is 68º, and I've also read that partial-boils usually have enough Oxygen as well. Also, it's dry yeast (about a year before the expiration date) that I've added to warm water. One beer I used a starter, but the same results.

So my question is, what would you recommend I do to fix my routinely sticking beers? Add nutrients, agitate the beer, repitch, wait it out? It's happened on my last 3 batches, so I'm thinking it's a process issue more than specific ingredients, etc.

Thanks in advance!!

this is a tricky one. it could be quite a few things that are causing this to happen. first off, do you know what kind of dry yeast you are using? second, how warm is the water you are rehydrating in? lastly on the yeast topic, how are you aerating your wort prior to pitching?

ingredients-wise, some extracts are not as fermentable as others. it COULD be that the extract you're using just isn't very fermentable. i've never used these kits, so I don't have any experience to compare to, but hopefully someone else can shine some light there. maybe try a different kit from somewhere else to see if that changes things?

If the kits are coming with anything but light extract and then having you do a concentrated boil for 60 minutes that may be part of the problem. The extract brews that I've done and have seen people do that hit a decent terminal gravity are the ones starting with a very light extract and the bulk of it added at the end of the boil. Also if you are racking too early it'll finish high. How long are you leaving in the primary fermentor?

When people say that extracts are not as fermentable as others they are talking about the difference of a beer finishing in the low teens as opposed to the high teens. If you aren't getting mid teens on a 1.050 beer the problem probably isn't the extract unless it is absolute crap.

Everything you said pushes me to think you are looking at a yeast health issue. Yes, malt has nutrients but you will help yourself by adding nutrients to give them what they need for optimal health. Can a soldier operate on a ration of bread, bologne, and water...sure, but feed him a square meal with balanced protein, carbs, fat, and adequate vitamins and he will have far more stamina for the long fight.

Make sure you are hydrating your dried yeast properly.

Use a good brand of dried yeast.

Hit the beer with O2, shaking is great and all, but won't get you to the optimum levels.

Keep your fermentation temp stable...if you let the temp ramp up as it does naturally then drop off after the exothermic reaction dies down your yeast will peter out early. Either keep the temp down in the first place don't drop it after it has ramped up...this will take consideration in your consideration of what equipment you have. If you don't have the ability to keep the temp from ramping up you might want to consider starting the ferment a little cooler so the ramped up temp is in the range you want (ie start at 65, let it ride up to 68, and then hold it there).

What yeast are you using? Windsor, Coopers standard, Muntons standard, and many no-name yeasts are low attenuators. Use something like Nottingham, S-04, or US-05; there are many other good ones too.

Aerate the wort well. Just adding cold water does add some oxygen, but not enough. Cap the carboy and shake the heck out of it. It should start to form a foam on the top. That should be enough.

For your current beer. I would recommend making a small beer (about a gallon; use 1 lb of extract), shaking it to get it really aerated, adding new yeast to it, and when it gets going, pour the whole lot, including sediment, into the original batch.

Android - Not sure what type of Dry Yeast it is specifically; I didn't special order it or anything, so I'm thinking it's just Muntons or something.

PT Ray - The latest recipe was mostly light liquid extract, then some Extra Dark DME, Candi Sugar, Honey (it was a poor-man's under-researched Belgian Triple). I was thinking it might be an unfermentable issue, except that this latest beer is 2 weeks into Primary and has capped at 1.042, which is WAY high for an FG.

Bensiff - I'm not doing anything to aerate the wort; I've heard that once you add your yeast, you just let it sit there; no shaking or stiring or anything else. Should I be shaking the cooled wort before pitching, hoping to increase O2 in the wort?

Calder - Typically I was switching to a secondary after 2 weeks, then bottling after 4 more weeks. I've noticed that the gravity doesn't change from pre/post secondary, so I don't think it's just slow, it seems flat-out stopped.

Given that I'm not doing anything to address aeration, should I do something "drastic" like shake up my carboy? Or repitching/Calder's idea of a mini-batch? Lastly, my Joy of Homebrewing book says that leaving a beer in primary for more than about 3 weeks will produce off-flavors. Should I be worried about that?

Thanks for the fast replies!!

You want to aerate the wort, that is not "drastic" just a part of the process. Best case is to add pure O2; however, for standard gravity beers shaking the crap out of the fermentation vessel for a few minutes will get you by...and yes, do it when cooled. Here is what I would do based off what I know...

Get a quality yeast like Safale..as mentioned, properly hydrate before pitching, aerate your wort, control the temp, get rid of the secondary and let it sit on the yeast for a good month (it doesn't matter if the gravity is terminal, the yeast are still cleaning up and conditioning the beer).

On a low to mid gravity beer this should be more than adequate to get good results. For high gravity beers you need to work harder and do stuff like shake the carboy when the yeast starts to settle, use nutrients, hit it with pure O2. Use Mr. Malty's pitching rate calculator to determine how much yeast you need.

Bensiff said:

You want to aerate the wort, that is not "drastic" just a part of the process. Best case is to add pure O2; however, for standard gravity beers shaking the crap out of the fermentation vessel for a few minutes will get you by...and yes, do it when cooled. Here is what I would do based off what I know...

Get a quality yeast like Safale..as mentioned, properly hydrate before pitching, aerate your wort, control the temp, get rid of the secondary and let it sit on the yeast for a good month (it doesn't matter if the gravity is terminal, the yeast are still cleaning up and conditioning the beer).

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So just to clarify, you're saying that prior to pitching yeast I should be shaking the beer to aerate it, then I pitch yeast onto it and leave it alone? Also, "get rid of the secondary", meaning don't bother with it? I guess I don't understand the point of a Secondary then; I'd thought the benefit was in that you're letting it condition longer before bottling, but not so long as to let Autolysis to start?

Bensiff said:

On a low to mid gravity beer this should be more than adequate to get good results. For high gravity beers you need to work harder and do stuff like shake the carboy when the yeast starts to settle, use nutrients, hit it with pure O2. Use Mr. Malty's pitching rate calculator to determine how much yeast you need.

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As for "shaking the carboy when the yeast starts to settle", does this disturb the process at all? I was told just to let the yeast do it's thing, not to shake it or aggitate it or anything. Should I try shaking my bucket now, or will that not gain me anything after I've pitched?

Sorry for the rookie questions, just not sure what to do at this point. And I'll check out Mr. Malty's right now, thanks!

Bensiff said:

You want to aerate the wort, that is not "drastic" just a part of the process. Best case is to add pure O2; however, for standard gravity beers shaking the crap out of the fermentation vessel for a few minutes will get you by...and yes, do it when cooled.

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Shaking the crap out of the fermenter has worked perfrctly well for me. I see no reason to use O2. If I'm not mistaken, too much O2 can kill the yeast. Somewhere there is a happy medium.

leechdemon said:

So just to clarify, you're saying that prior to pitching yeast I should be shaking the beer to aerate it, then I pitch yeast onto it and leave it alone? Also, "get rid of the secondary", meaning don't bother with it? I guess I don't understand the point of a Secondary then; I'd thought the benefit was in that you're letting it condition longer before bottling, but not so long as to let Autolysis to start?

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Correct. I use secondary for various reasons, but have left beers in Primary for several weeks with no problems. Don't worry about autolysis unless you are conditioning beer for several months or at high temperatures.

leechdemon said:

Should I try shaking my bucket now, or will that not gain me anything after I've pitched?

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I would say no. The yeast are past the reproductive stage. That's why I sugested making a small beer to get a decent yeast population and add that to the main batch.

It's always a good idea to check your tools. Get some distilled water and find out what your hydrometer is telling you. It should read 1.000 @ 60 F

you definitely need to aerify (oxygenate) the wort prior to pitching. yeast needs some oxygen to work through the reproduction phase, i would bet that is a big part of your yeast stalling out. there are numerous ways to do this. the simplest is shaking it wort once you have it in a fermenting vessel; also, you can pour it between two sanitized buckets if that's all you have. 5-6 back and forths should be good to start.

As for "shaking the carboy when the yeast starts to settle", does this disturb the process at all? I was told just to let the yeast do it's thing, not to shake it or aggitate it or anything. Should I try shaking my bucket now, or will that not gain me anything after I've pitched?

Sorry for the rookie questions, just not sure what to do at this point. And I'll check out Mr. Malty's right now, thanks!

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I wouldn't "shake" the carboy, but you can put it on the carpet and gently rock it around (with the airlock on!). After a few rotations the beer inside should start swirling. Keep it up until most of the sediment on the bottom is resuspended. Do that once a day or so. You don't want to introduce any air into the wort once fermentation has started, but gently swirling the yeast back up into suspension can sometimes kick them in the butt just enough to get them to finish the job.

No need to apologize for questions.

OK, now I'm going to really confuse the issue. Check out this series of interviews with brewing expert, Eric Watson, on Beer Tools:

http://www.beertools.com/html/articles.php?view=245

Here's Eric's surprising advice on aerating wort:

"If possible, don't! The reason is that it is not the wort that needs the oxygen, it is the yeast. By oxgenating the wort instead of the yeast starter, it will cause an over production of cells due to the excessive oxygen presence. This then leads to the production of unwanted esters and higher alcohols that will compromise beer flavor."

So it's actually the starter you want to aerate.

He continues, "When oxygenating starters, you cannot use pure O2... the reason is that the uptake occurs too fast and without a dissolved O2 meter ($$$), you cannot tell when to stop. The way to properly do this one is to aerate using a high pressure aquarium pump, sterile air filter and a stainless steel aeration stone, all of which are redily available. It is virtually impossible to over-aerate using air, so you will avoid oxygen toxicity problems that will occur if trying to do this with pure oxygen."

When using dried yeast, he recommends NO AERATION at all. The yeast was properly aerated before drying and has been properly prepared for the fermentation immediately. Just rehydrate the yeast (he recommends 90deg water) for 30 minutes and dump into the non-aerated wort.

That's some wild and crazy stuff, huh?!!!

My personal experience backs up the oxygen toxicity problem. I used to pitch the yeast then aerate with pure O2 for several minutes. The result was huge lag times, slow ferments, and high final gravity.

Yeah that's interesting. I don't think I will take it as mantra without more research, after all the guy is saying that anything other than a 20 minute single infusion mash is all anyone needs. I'll put that right there with the add banners that say, "the one trick you need to know for a flat stomach." I won't argue that you can get full conversion in as little as 15 minutes with the right parameters; however, getting the right fermentability can take much longer.

As far as the O2 issue, yeah, your goal is providing yeast with O2 so they can reproduce healthy cells. There is a balance for sure, too much is bad, too little is bad. I use 1 minute of O2 added while swirling my carboy and that is it. I can't say if it increases lag time (probably does as there is much evidence that says it does); however, it is enough to get me thinking about experimenting more with how much time I expose it to the O2. But, in the end it is about finding the balance that gives the correct amount of yeast growth.

leechdemon said:

So just to clarify, you're saying that prior to pitching yeast I should be shaking the beer to aerate it, then I pitch yeast onto it and leave it alone? Also, "get rid of the secondary", meaning don't bother with it? I guess I don't understand the point of a Secondary then; I'd thought the benefit was in that you're letting it condition longer before bottling, but not so long as to let Autolysis to start?



As for "shaking the carboy when the yeast starts to settle", does this disturb the process at all? I was told just to let the yeast do it's thing, not to shake it or aggitate it or anything. Should I try shaking my bucket now, or will that not gain me anything after I've pitched?

Sorry for the rookie questions, just not sure what to do at this point. And I'll check out Mr. Malty's right now, thanks!

Click to expand...

Yes, shake the crap out of the carboy once it is cooled to pitching temp then add your yeast (I prefer to add yeast after, but probably no reason you can't before shaking).

As far as I can tell point of a secondary is so homebrew shops can sell you more equipment. In practical terms they are good for for extremely long term bulk conditioning, freeing up a carboy to ferment another, or when you are doing things like fruit additions. Do not worry about autolysis, you can leave your beer on the yeast for months with no ill effect.

Rousing the yeast towards the end of fermentation is fine, in fact there are many yeast strains (particularly highly flocculant ones) that you need to rouse to get them to hit your FG...I just had a 1.070 Biere De Garde peter out at 1.024 and after agitating it regularly it finished down at 1.010 with no problems. Make sure you have a solid seal so you are not getting oxygen mixed into the beer.

No worries about rookie questions...and I encourage you to keep asking them and to go out and seek answers on your own too, reading multiple resources is the best educator.

android said:

this is a tricky one. it could be quite a few things that are causing this to happen. first off, do you know what kind of dry yeast you are using? second, how warm is the water you are rehydrating in? lastly on the yeast topic, how are you aerating your wort prior to pitching?

ingredients-wise, some extracts are not as fermentable as others. it COULD be that the extract you're using just isn't very fermentable. i've never used these kits, so I don't have any experience to compare to, but hopefully someone else can shine some light there. maybe try a different kit from somewhere else to see if that changes things?

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It's not the extract.

Ray

Bensiff said:

As far as the O2 issue, yeah, your goal is providing yeast with O2 so they can reproduce healthy cells. There is a balance for sure, too much is bad, too little is bad. I use 1 minute of O2 added while swirling my carboy and that is it. I can't say if it increases lag time (probably does as there is much evidence that says it does); however, it is enough to get me thinking about experimenting more with how much time I expose it to the O2. But, in the end it is about finding the balance that gives the correct amount of yeast growth.

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I switched back to aerating wort with an aquarium pump and stone which dramatically improved the fermentations, but I would think if you were cautious with the O2 and pitched the yeast AFTER aerating, you could also obtain good results.

The next batch I do I am going to use rehydrated dry yeast without aeration and see what happens. It should be interesting.

I've never used dry yeast so I can't speak to that...I have done a lot of research and understand the benefit of O2, to me lag time only means healthy growth is going on...well, as long as the actual fermentation goes accordingly. I ferment beers out in about 4 days, so I know I'm doing something right. But, experimentation is half the fun.

leechdemon, Start by using a brand of yeast with a solid track record that comes in a packet dated for freshness. It's hard to go wrong with Fermentis S-05 or S-04. Follow the re-hydration instructions on the Fermentis website:

http://www.fermentis.com/fo/60-Beer/60-11_product_rangeHB.asp

Temperature stability during fermentation is important. Some say aerating the wort is not necessary when using a full 11.5 gram packet of dry yeast per 5 gallons. But it probably won't hurt and aeration may save the fermentation if some percentage of the packet is not viable. (You don't always know how the packets have been stored.)

Shaking of rocking the fermenter for at least at full minute is a time honored method of getting some O2 into the wort.

Don't ever use distilled water to re-hydrate dry yeast. Bottled drinking water--with trace minerals-- okay.

Alright, as suggested I've made a 1gal mini-batch of beer similar to the style of my latest stuck batch. This time I shook the bejesus out of it for a full 5 minutes. I hydrated 11g of fresh Nottingham yeast (what the yeast calculator suggested for my original batch) for 15m and pitched it.

I'll let you guys know how it goes. Thanks again for your help!

leechdemon said:

Alright, as suggested I've made a 1gal mini-batch of beer similar to the style of my latest stuck batch. This time I shook the bejesus out of it for a full 5 minutes. I hydrated 11g of fresh Nottingham yeast (what the yeast calculator suggested for my original batch) for 15m and pitched it.

I'll let you guys know how it goes. Thanks again for your help!

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That seems like you are doing nothing more than making an elaborate over sized starter, you shouldn't need to do such things to get a good fermentation.

Well, if I'm getting stuck based on low oxygen, supplying new oxygen in the form of a large starter should help, correct? If I'm oxygen-capped, what else will fix the batch, aside from shaking my carboy?

Its really hard to know what the problem is, its more figuring out what it is not. If it is an oxygen problem then you can overcome that by dumping the wort into the fermentation vessel in a manner that agitates it greatly and then shake the crap out of it. That alone will give you enough oxygen for most fermentations, it will not give you ideal volumes, but that gets more into cell wall health as they multiply which will come into greater importance if you are repitching the yeast for successive generations...something to start considering when you want good consistent results. What you are doing is abnormal, in fact I have never heard anyone suggest it. It doesn't make it wrong; but, it is a lot of uneeded work given the correct pitch of properly rehydrated yeast, some O2, yeast nutrients, and temp control will do the trick every time (assuming you mashed your grains correctly).

leechdemon, I've probably missed something. But are you pitching an 11 gram packet of Notty--that's a huge number of yeast for 1 gallon --into the 1 gal. mini-batch in order to re-start a stuck ferment, or to start a new ferment?

Re-hydrating dried yeast and making a large liquid starter are different processes. Of course, if what you are trying works, that's great.

Good luck and keep us updated.

One of the suggestions someone gave was to use a Yeast Calculator, along with good yeast. The calculator recommended 11g, and I only pitched 5g. One of the "good yeasts" at my LHBS was Nottingham, available in 11g, so I grabbed some.

Another suggestion I was given, in order to fix the "not enough oxygen" problem, was to do a 1 gallon mini-batch that i shake the hell out of. In theory, shaking the mini-batch should provide enough oxygen for THAT yeast to go through respiration properly, and hopefully get transferred over to the full batch.

So yeah, I used 11g of Yeast on a 1gal batch, knowing that it was about 5x as much as I need. But the idea was that it was the correct amount of yeast for a 5gal batch, and when I merge the mini batch with the full batch, it'll balance out.

After about 7 hours I got some decent bubbling, and after about 16 hours my girlfriend called me at work to scold me for scaring her like that... apparently the cap blew off my mini-batch and scared her a bit. I'm taking this as good news, since usually my ferments are pretty mild and lackluster, visually. So when I got home from work, I merged the active starter with the full batch (at around 23 hours), and this morning (34 hours) it's still bubbling, although a bit slower. I imagine there's some lag time involved in merging, as well as the fact that 1gal worth of oxygen has to fill a 5gal bucket's headroom.

Anyways, looks like it's going alright. I'll keep you guys posted in another week or so! Thanks again!

Please post your recipe.... Please include amounts of each...

Reason - you mention Candi sugar and Honey - both are known for being horribly low in nutrients and will produce stuck fermentations galore....

You may need to throw in a pinch of DAP or some yeast nutrient for good measure....

Thanks

Here's the recipe I used; it was basically adapted from what I'd read before going to my LHBS... and further adapted from the really low selection available at the time.

Crazy Triple

6.6# Light Malt Syrup
1# Muntons Extra Dark DME
1# Weyermann Caramunich 3 - 2 Row Barley
1# Light Candy Sugar
1 Cup Clover Honey (0.75#)
1 Cup Robust Molasses (0.75#)

1 Tsp Cloves
2 Tsp Lemon Zest

1.5 Cups Wild Hops (Boil)
0.5 Cups Wild Hops (2 Min)

1 Packet (5g) Dry White Wine Yeast

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The Yeast was what I had on-hand from a Hard Cider I was working on, and is obviously not my normal choice. The Hops is Wild Hops I got from a friend. It was frozen and undried, so I have no way to guage the strength, and mostly just guessed.

I figured that since 70% of the sugar comes from Syrup/DME, I wouldn't have too much of a problem "winging it" like I did. The Candi/Honey shouldn't be a problem with that much base malt, should it?

I think you will be fine, pushing the sugar amount kinda high though. You might consider adding some of the sugar (like 1/2) as fermentation starts to slow up some so as to not end up with yeast favoring the simple sugars and forgetting about the maltose. Maybe someone with more experience in dealing with high levels of sugar can pipe in to confirm that though, I usually don't go much above 15%.

Huh, that's an interesting idea. So you're basically only throwing in the easy work (Candi, Honey) after the Yeast are through with the hard work. Neat idea, I'll look into that.

Yeah, I know it is commonly done when using a lot of sugar; however, I have never done it so I figure some of the guy's who brew a lot of Belgians might have some good input on this issue for you.

+1 on adding most of the simple sugars near high krauzen during the ferment for better attenuation.

leechdemon said:

Alright, as suggested I've made a 1gal mini-batch of beer similar to the style of my latest stuck batch. This time I shook the bejesus out of it for a full 5 minutes. I hydrated 11g of fresh Nottingham yeast (what the yeast calculator suggested for my original batch) for 15m and pitched it.

I'll let you guys know how it goes. Thanks again for your help!

Click to expand...

Alright, it's been a few weeks, here's where I'm at.

To review, SG was 1.068, it stuck after about a week at 1.042 and held steady for a week. Someone suggested an O2 problem, so I made 1gal of the same recipe and shook the fermenter like hell for 5m. After 1 day it peaked, and I added it to my main batch. I checked it after 2 weeks, and it dropped to 1.022. I checked it again yesterday (3 weeks after the mini-batch addition) and it's still at 1.022, so I think it's stopped again.

What I think has happened was that the mini-batch provided more than enough O2 for a single gallon of wort, and, as hoped, carried over to partially supply the original 5gal batch with more much-needed oxygen. The Gravity dropped, but not all the way. I'm thinking that 1gal simply can't hold enough oxygen to supply a 5gal batch, and that my fermentation went as far as it had the oxygen to go. So if 1gal got it a 0.020 drop, a second gallon would have enough O2 to drop it from 1.022 to wherever the FG will end up.

So, I'm thinking the last fix will be a second gallon addition, well aerated, to provide the remaining oxygen needed to get to FG. If that works, then I think the problem would be correctly diagnosed as a lack of oxygen. I'm definitely planning to give a vigorous shake the next time I do a full batch, and prevent this problem altogether.

Anybody got any opinions on the contrary? Am I tempting fate with too many additions and checks?

Minky said:

OK, now I'm going to really confuse the issue. Check out this series of interviews with brewing expert, Eric Watson, on Beer Tools:

http://www.beertools.com/html/articles.php?view=245

Here's Eric's surprising advice on aerating wort:

"If possible, don't! The reason is that it is not the wort that needs the oxygen, it is the yeast. By oxgenating the wort instead of the yeast starter, it will cause an over production of cells due to the excessive oxygen presence. This then leads to the production of unwanted esters and higher alcohols that will compromise beer flavor."

So it's actually the starter you want to aerate.

He continues, "When oxygenating starters, you cannot use pure O2... the reason is that the uptake occurs too fast and without a dissolved O2 meter ($$$), you cannot tell when to stop. The way to properly do this one is to aerate using a high pressure aquarium pump, sterile air filter and a stainless steel aeration stone, all of which are redily available. It is virtually impossible to over-aerate using air, so you will avoid oxygen toxicity problems that will occur if trying to do this with pure oxygen."

When using dried yeast, he recommends NO AERATION at all. The yeast was properly aerated before drying and has been properly prepared for the fermentation immediately. Just rehydrate the yeast (he recommends 90deg water) for 30 minutes and dump into the non-aerated wort.

That's some wild and crazy stuff, huh?!!!

My personal experience backs up the oxygen toxicity problem. I used to pitch the yeast then aerate with pure O2 for several minutes. The result was huge lag times, slow ferments, and high final gravity.

Click to expand...

So if you're running your starter on a stirplate for two days, with a vortex, are you pulling in enough oxygen for more than adequate oxygenation of your starter? Hmm.

I'm getting a little confused in sorting out your past problems of high FG vs the stuck fermentation you have now. Stuck ferments are a special animal. I think you may reach a point where further meddling with this batch could do more harm than good. If it tastes decent--especially after aging and regardless of the FG--you might just bottle it up and plan for your next batch. Or set it back in secondary for a month in the meantime.

As for why you are having repeated low attenuations-- As said above, there can only be so many reasons. Healthy dry yeasts are usually go-getters. You might check into a product for re-hydrating dry yeast called 'Go Ferm'. Go Ferm is used only for re-hydrating dry yeast. This in conjunction with a yeast nutrient in the wort should mostly rule out problems at the start of fermentation. That's assuming re-hydrating procedures are correct and the yeast ain't fried in the sachet.

The advice to check your hydrometer is also a good idea. They can be as off as any other tool.

Hope this helps.