Help. My Ag Has Stopped At 1030

[rosswill]

I hope you can help. I'm fairly new to AG with only 5 brews under my belt. I seem to have trouble getting my AG's to ferment out (never had a problem with kits). My past batches (all pilsner/lagers) stopped at around FG 1020. The current batch I have on the go has stopped at FG 1030.

I initially thought the proplem may be airation, and after reading the many threads on this issue I am now absolutely confused. This is what I have done so far....

After the wort was cooled I transfered it to the fermenter letting it splash. I also have drilled holes into the tube to act as a venturi. I then put the lid on and shook the sh*t out of it. I then added the yeast (Wyeast Pilsner Urquel Smack Pac) Left it out overnight to get yeast working (air lock was bubbling) and then put it in the fridge @12 degrees. It went OK for about a week and then stopped. I took it out of the fridge and let it warm up to 20 degrees and again shook the sh*t out of it. It bubbled weakly for another day and stopped again. I left it for a week back in the fridge and then let it warm up again to 20 degrees and threw a packet of Saflager yeast into it. Left it overnight and it again started to bubble again weakly. Back into the fridge again at 12 degrees.

So, it is now 3 weeks down the track it has stopped again, and the gravity is now 1028. What do I do? Is it ruined? Can I get it stated again? If so, how? What am I doing wrong?

 

[Prawned]

Is your hydrometer working right? does it read 1.000 or what ever it is in water?

 

[rosswill]

Yes,
My Hydrometer is fine. I just bottled a cider that got down to 1002

 

[Adamt]

You don't seem to be having trouble with kits fermenting out, so must be something to do with your AG process.

What temperature are you mashing at? Is your thermometer calibrated? What recipes are you using?

 

[bakkerman]

How much wort did you pitch on?

I find with 23 liter batches of pilsener i need a well aerated starter.

From what you're saying I'm guessing you did not get enough oxygen in the wort with the splashing, and that there were not enough yeast cells to get it going all the way.

I made the same mistake recently and now have a load of under attenuated "pilsener"

 

[benno1973]

What temperature are you mashing at? Is your thermometer calibrated?

Yep, what temp are you mashing at? Might be too high? And check the thermometer...

 

[itguy1953]

If the high SG is caused by maltodextrin (long chain sugars that yeast cannot breakdown), you could add some enzyme to your brew which will break down the maltodextrin into fermentable sugars. These enzymes are sold to help "dry" out your beer.

Trade names are improzyme and modiferm. You can get them at your local HBS. I used improzyme recently and it dropped the SG from 1.015 to 1.010. I had the wort stuck at 1.015 for a week, and the SG would not move down. It was very sweet to drink, the result of residual sugars.

Now that it is at 1.010 it is not so sweet, but as I added 1.2kg of LME to a can of Coopers Bavarian Lager, the balance of sweetness and bitterness is wrong. I am going to add some isohops tomorrow to get the IBU up and balance the beer out.

Barry

 

[Ross]

rosswill - Unlikely to be a pitching rate problem, almost certainly your mash temperature.
Test your thermometer in boiling water (100c) or find another to compare against. Mash in the lower range 63c to 65c.

cheers Ross

 

[shonky]

rosswill - Unlikely to be a pitching rate problem, almost certainly your mash temperature.

I tend to disagree with this, unless the mash temp was in the high 70's I don't believe you would end up with a beer finishing this high. Mashing at say 69-70 may result in a higher dextrin wort perhaps finishing at 1018-20 ish, but 1030! I suppose its possible that the thermometer is that far out so definitely worth checking but I agree with bakkerman and would be looking at your aeration and also check your pitching temp and pitching cell count ie. making a starter, especially for lagers.

Cheers

 

[Ross]

Any amount of yeast will normally finish an average brew. I've pitched lagers more than once with just 1/8th of a smack pack with no starter or aeration & its finished fine (although a horrendous lag time).
Consitant poor attenuation, where his other non-AG brews are finishing fine, points towards far too high a mash temp.

cheers Ross

 

[Online Brewing Supplies]

How much wort did you pitch on?

I find with 23 liter batches of pilsener i need a well aerated starter.

From what you're saying I'm guessing you did not get enough oxygen in the wort with the splashing, and that there were not enough yeast cells to get it going all the way.

I made the same mistake recently and now have a load of under attenuated "pilsener"

In this case (1030) I would be looking down this track , water chemistry could also be strange , too much Iron not enough Zinc etc , I would try using yeast nutrient INFO HERE for higher attenuation rates. 1020 finishes could be a mash temp problem but at 1030 it looks like yeast related. Really need to have all the info ( Sg's ,mash temps) to have an accurate guess .
GB

 

[Screwtop]

My money's on thermal shock. Getting the yeast going at a high temp then dropping the fermentation temp is a method I read about and tried last year. When I used this method for a couple of bock's they stopped @ 1.026, the yeast simply stopped when the fermentation temp was dropped to 10C. Pitched the next batch at 10C and all went fine, down to 1.017 which is where the average attenuation for the yeast should have finished. Maybe the yeast would have continued on if I had left it in primary for long enough as lager yeasts tend to. Was not very experienced with lagers at the time so I believed fermentation had ceased.

Screwy

 

[Darren]

Mash temps don't make that much difference.

Yeast health is the most likely cause.

Try pitching more next time.

cheers

Darren

 

[T.D.]

I tend to disagree with this, unless the mash temp was in the high 70's I don't believe you would end up with a beer finishing this high. Mashing at say 69-70 may result in a higher dextrin wort perhaps finishing at 1018-20 ish, but 1030! I suppose its possible that the thermometer is that far out so definitely worth checking but I agree with bakkerman and would be looking at your aeration and also check your pitching temp and pitching cell count ie. making a starter, especially for lagers.

Cheers

I was just about to reply to say the exact same thing Shonky. Whenever making a Mild or a light beer where I wanted a high FG (say 1.016-17) I would only mash at 69. This translated into a situation where you get a FG of 1.030 would mean a mash temp that was so high it would almost impossible to do unintentionally.

My money is on a combination of an inadequate starter volume and possibly fementation temp being a little on the cold side (even if you don't *think* it is, it may well be in reality). I had a run of high FGs way back and the reason was my starters weren't quite big enough. Most of the time I got away with it but when the cooler weather came around the cold nights was all I needed to get a stuck ferment (this was before I had a fermentation fridge).

Worth sticking with the liquid yeasts though, the flavours are well worth it, but I would recommend going a bit more "all out" on your starters and seeing if that helps. Maybe pitch on the cake of the previous batch would be a good test to see if its pitching rate that is the problem.

 

[T.D.]

Any amount of yeast will normally finish an average brew. I've pitched lagers more than once with just 1/8th of a smack pack with no starter or aeration & its finished fine (although a horrendous lag time).
Consitant poor attenuation, where his other non-AG brews are finishing fine, points towards far too high a mash temp.

cheers Ross

Long lag time aside (as we all know this is not desirable in any brew), it certainly is the case that a low cell count can lead too a high FG. If the beer is fermented at high-ish temps you may get through without a hitch, but when the yeast is stressed (ie not enough of them) the combination of a low-ish temp and a rising alcohol level as the beer nears terminal gravity will almost definitely cause it to stall. Its all about equilibrium - the point where the factors working against the ferment (low temp, alc level, yeast numbers etc) equals the factors working for the ferment is where the FG will lie.

 

[Insight]

You say you are using a hydrometer, rather than a refractometer? Just checking, because a refractometer only reads correctly pre-fermentation. You need to apply a formula to your brix reading post-fermentation to get your FG. There's been more than a few of us caught by that one

Otherwise, I'd agree with yeast health being the issue. Pitching the dry yeast into an low PH/high alcohol environment is unlikely to move the SG much. You could build up another active starter and pitch at high krausen to get the thing moving again.

 

[Screwtop]

Mash temps don't make that much difference.

+ 1

Screwy

 

[rosswill]

Hey all, thanks for the help.
I think AdamT, Ross& Kaiser Soze might be on the money, though the problem could be a combination of a number of the points raised. I use an insulated thermostat controlled boiler/masher to make my AG's. The first 4 AG's the thermostat held the mash at exactly 66 degrees. When I made this one, the thermostat went on the blink and the average mash temperature would have been around 70-72 degrees. I kept switching it off and stirring to drop the temp. I took a while before I realised I had a problem with the thermostat. I knew what had happened was not ideal, but I had no idea it would cause this type of problem. I think I might ditch the boiler/masher and get more conventional equipment.

To answer some of the other questions:
OG was 1050.
So far, I have only made pilsners (Urquel and Grolsch clones with 5 kg of grain) and without wanting to sound immodest, they were rippers. Love that Saaz.
I went home last night and tested my hydrometer. It is fine. I do not have a refactometer.
I make 23 litre batches.
To prepare for pitching, I broke the widget inside the smack pack, shook it up and left it for 6 hours to swell up prior to pitching. I must admit, it did not seem to swell up as much as I expected. I did not make a starter or aerate the yeast prior to pitching. This is the first time I have used smack packs.
Does the fact that the Saflager I later pitched only briefly brought it back to life mean that the wort has finished fermentation at 1028?
Will the 'Dry enzyme' mentioned by Barry R get the wort going again, or is it jiggered?
What do I do now? Is there anything I can do to rectify the situation, or do I just keg it and see how it tastes?

Interesting comments from Screwtop regarding thermal shock. After the yeast started at ambient and I put it in the fridge, it takes about 8 hours to drop to 12 degrees. Is that too quick. What is the collective wisdom on when/how to ferment at lower temperatures?
I sure have learnt a lot from this batch. Shame I may have sacrificed a batch in the process.

 

[mika]

Best to make a starter, but that should have been enough yeast for the job though it's starting to get iffy at that sort of SG.
Mash temp looks to be the big one, I take it there was a bunch of crystal malts in this beer ?

I mashed at 68 to produce that bigger bodied beer, yeah...lots of crystel malts, 1024 is where she stopped and just like you've encountered, nothing gets it moving again.

The Dry enzyme is probably going to go nuts on it and unless you watch it like a hawk and some how kill the yeast it's going to ferment out way dry for the style. Guess if you wanted to experiment. Without a bucket load of hops in there it's going to be a pretty sweet tasting beer and unfortunately only going to get worse.

 

[Ross]

I think some of you may be missing the point here.

rosswill has done 5 ag's & they have all finished high. His previous brews it would appear have not.
Therefore yeast pitching rates IMO is unlikely to be the main cause. Certainly the one very bad result he's just got could be a combination of events, chilling too early, low pitching rates, poor PH levels, coupled with high mash temps. But to get consistant 1020 finishing gravitys, I would first be checking my mash temps & then working through the other possible causes.

Cheers Ross

Edit: started this post before rosswill's latest post - got caught with a long phonecall, mid posting....