Help. My Ag Has Stopped At 1030

[Screwtop]

Mash temp looks to be the big one, I take it there was a bunch of crystal malts in this beer ?

Wouldn't have thought this to be the case mika, as he's been making Urquell and Grolsch clones. Can you clear this up for us rosswill ?

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.

That's exactly what happens when there are lots of long chain sugars in the wort.

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.

Drop the temp to 0C when the gravity reaches the desired level and keg for lagering, the enzyme carries out conversion, it's the yeast that''s fermenting the new simple sugars, chill the wort and the yeast will sleep as normal, although some very slow fermentation will still occur at low temps with lager yeasts.

 

[Back Yard Brewer]

+ 1

Screwy

And again +1 +1 = 2

 

[T.D.]

Even at 70 or 72 degrees, I can't see that being enough on its own to get an FG of 1.030. As I said, I have mashed at 69deg to achieve just 4-5 points above my usual FG. But here we are talking about finishing **20** points above your expected FG! That's a lot, and certainly not something I would attribute to mash temp. And like Screwtop said, an Urquell clone would not be heavy in crystals - quite the opposite. If mashed at 72 degrees I would expect an FG of around 1.018-19, but definitely not 1.030.

 

[Jazzafish]

Mash temps don't make that much difference.

Yeast health is the most likely cause.

Try pitching more next time.

cheers

Darren

Not true, all parts are involved.

The mash temp creates your fermentables. Makes a big difference. On a commercial scale I have seen 0.5*C make a large difference to the final gravity. Need to get this right first.

Once the conversion is sorted it comes down to the yeast and its working environment.

My experience suggests underpitching tends to give off more estery issues before gravity problems. Has to be severly under pitched to cause a stuck ferment without infection.

Thermal shock will also cause alot of issues. Some yeasts are a bit more forgiving though.

 

[T.D.]

Not true, all parts are involved.

The mash temp creates your fermentables. Makes a big difference. On a commercial scale I have seen 0.5*C make a large difference to the final gravity. Need to get this right first.

I agree it is a combination of several factors, not just one. But even if there is a heap of crystal malts as well as an extremely high mash temp, I highly doubt such a beer would stop at 1.030 if the yeast starter was healthy and large enough.

Do you work at this brewery? How many gravity points did the 0.5deg change in mash temp account for?

Get the mash temp right by all means, but it still doesn't explain how the FG finished 20 points higher than normal in a beer with minimal crystal malts.

Its impossible to be 100% certain, but usually the combination of "lager", "liquid yeast culture" and "high FG" very ominously points towards starter size/health.

 

[mashdog]

Tip it out.

I kegged a couple of my first AGs that stopped at 1020 to see how they would turn out. They were crap and got tipped out anyway. Not worth the CO2 and fridge space.

If you like, you can try adding dry enzyme as this will give an indication as to where your issue lies. Eg, if the ferment starts again, then you have a mash/temp problem and ended up with a lot of non-fermantables. If the ferment does nothing (which i suspesct will be the case) you probably underpitched or otherwise stressed your yeast.

Proper yeast pitching solved my AG attenuation problems. I know wyeast say that the activator smack packs (100Billion cells) are enough to pitch into 5 gallons (about 20L) at the rate "recommended by professional brewers". But checkout http://www.mrmalty.com/calc/calc.html - It will tell you that you need about 200Billion cells in a starter for an ale and double that for a lager. Activation of a smack pack doesn't significantly increase the cell count either. So assuming the pack has been handled correctly all the way from the US to you (unlikely), you're already underpitching.

The solution... make a starter. It's easy and allows you to save money by reusing yeasts.

Also, i know many people recommend wort aeration. I previously thought it was the thing to do and recommended it on a previous thread. However, i have now come to the conclusion that it is just a "stop-gap" remedy for underpitching. The only reason you need oxygen is to increase yeast cell count. If you are pitching sufficient amounts of yeast to attenuate your beer, you have no need for oxygen.

So your starter should definately be aerated (a magnetic stir plate is ideal), but your wort should be as air-free as you can manage. Aerating it will only cause oxidation of your wort producing various undesireable flavours and aromas.

Hope that helps.

 

[maltedhopalong]

As far as I can see, there are no more fermentable sugars left. Throwing in a different strain of yeast still didn't get it going, neither did actively suspending the yeast in the beer (the phrase used was "shook the sh*t out of it"), it sounds like it's inside reasonable fermentation temperatures so I find it hard to believe it's a yeast problem. With that much early aeration and the fact that fermentation started well, it doesn't make sense for the yeast to just decide to pack it in, unless it was temperature shock, then that still doesn't explain why the saf couldn't get it going EVEN AT 20C!!

I personally subscribe to Ross's original thoughts about mash temperatures or something similar. Not 100% sure, it would be good if you could get a local AG brewer to come and watch you.

EDIT: Also, if your pilsners turned out with really high FG's and you liked them, I reckon you ought to keg this one too.

 

[mashdog]

Simply throwing more yeast in is unlikely to achieve much (nottingham yeast excepted - that stuff will attenuate water!) because the relatively high alcohol content of your semi-fermented beer will immediately piss the yeast off. it's a pretty harsh environment for native yeast to function in.

 

[mika]

Wouldn't have thought this to be the case mika, as he's been making Urquell and Grolsch clones. Can you clear this up for us rosswill ?

WTF was I thinking this morning :huh: I thought we were talking about a stout !
Yeah, mash temp will have an effect, but without lots of crystal in there it shouldn't be that significant.

 

[maltedhopalong]

That's not to say there isn't something else in the mash technique that's creating too many unfermentable sugars. For example, maybe you should post your WHOLE mash technique from start to finish and describe the materials you use, maybe the grain just isn't mashing for some reason?

 

[drsmurto]

So if you have a combo of high mash temps (72 was quoted), pitching one smackpack directly (no starter) into 23L of 1.050 lager wort i think 1.030 is probably not that strange. Wyeast recommend 2 smackpacks for a lager - i make a 5L starter instead.

Also noted he pitched at ambient and cooled down to 12 in 8 hours. I would think that the yeast has done bugger all in that time instead begin to replicate. Not used 2001 before, wyeast 2000 took 3 days to show signs of fermentation using a 5L starter so no idea of the lag time for this yeast.


FWIW - I got my mild to stop at 1.020 mashing at 70. OG was only 1.040 using wyeast 1187. 300g of crystal malt in a 20L batch. And i even made a 2L starter out of an activator smack pack!

 

[rosswill]

Hey Guys,
An update. Barry R's suggestion of adding some dry enzymes seems to have worked. I added some yesterday and it has come back from the dead. The wort still tastes OK, so luckily I havn't pick up an infection with all the handling.
I'll keep you posted on how much the enzyme drops the gravity.

 

[Guest Lurker]

Bear in mind that the idea of adding enzyme is to help pinpoint the problem for future brews, in all likelihood it will make this one taste like crap.

 

[Screwtop]

Hey Guys,
An update. Barry R's suggestion of adding some dry enzymes seems to have worked. I added some yesterday and it has come back from the dead. The wort still tastes OK, so luckily I havn't pick up an infection with all the handling.
I'll keep you posted on how much the enzyme drops the gravity.

So the sugars were there, the yeast was there, however it could not ferment the complex sugars in your wort. The enzyme is converting the complex sugars into simple fermentable sugars and all is moving as it should. Now is the time to disect your ingredients and processes to see why you produced a wort which was so unfermentable by this yeast strain, if that was really the problem. Yeast health plays a big part, a good healthy colony maybe could have done the job without the assistance of dry Alpha Amalyase Enzyme. If your able, and want to experiment, have a second batch ready to pitch onto the yeast from this one. After it's been through a ferment there should be plenty of good healthy cells (plenty of not so healthy ones also) for fermenting another batch.

All good learning, the beer will still be good, maybe not great but good.

Cheers,

Screwy

 

[rosswill]

Two days later still bubbling strong.
Although this has been a frustraiting experience, it has also been a great learning experience. There has been some great assistance and advice from fellow brewers who have been kind enough to reply.
Whilst I believe the problem was predominently caused by mashing at too high a tempertature due to thermostat failure, I believe aeration and yeast pitching rates and no starter contributed to the problem. Better aeration and yeast issues are easy to fix by adjusting practices. I have passed the electric masher/boiler on to SWMBO for her cheese making, and on the weekend brought myself a 50 litre boiler, 37 litre mash tun and gas burner. I am sure this will produce more reliable results.

 

[rosswill]

Kegged it on the weekend. FG 1010. Gravity sample tasted OK.
I pitched a Tooheys Old clone on half the yeast cake and it took off like a rocket within an hour. I guess there was nothing wrong with the yeast, it just had no fermentable sugar to eat. Mind you, I made it with my new gear (binned the thermostaticly controlled boiler/masher) and took great care to aerate the wort well.