fermentation not finishing

[Beersnob]

Just wondering if anyone out there knows why a fermentation doesn't get down to its projected gravity.
I brewed an all grain seasonal maple ale on saturday with my BIAB system, all went well although my mash temp was a little higher than I would have liked. I pitched white Labs English Ale 002 at around 20C. It started in around 12 hours of pitching, and stopped 4 days later but was very slow the last 2 days. OG was 1052 which was lower than the target 1061.This seems to happen to me regularly. I just checked the gravity now and its only down to 1030.
This isn't the first time this has happened to my fermentation. Does anyone have any advice? and is there any way to start this fermentation up again?.
Thanks in advance.
(Frustrated brewer)

 

[Tex083]

I listened to a podcast on the brewing network about attenuation and it had some great tips, as for finishing your beer off there are a few things that would help find the problem
1. Actual mash temp
2. Grain bill (crystal malts don't ferment out as well as base malts)
3. OG and projected FG (beersmith?)
4. Oxygenation
5. How much yeast pitched

If you want to finish it off John Palmer recommends adding a Lager yeast at Ale temp. Make 600mls starter and get it going and add to the beer, Lager strains are better at consuming large chain sugars.
Hope it helps

 

[timmi9191]

The grain - quality and % of toast and roast
mash temp
yeast nutrient
oxidising the wort
yeast health - age and pitch rate.

 

[philistine]

Not sure if this is relevant to your sitcho, but I recently moved from Melbourne to a town that has very highly chlorinated tap water.

My first 4-5 brews in our new place were, to be frank, f***ing s***house.
Apart from being f***ing s***house, they all shared a similar problem in that they never reached target gravity - even after 2 weeks in a well managed ferment.
It took a while to figure it out, as I was used to brewing with Melbourne tap water which in my experience is fine for brewing (Im sure some would argue tho), but after a particular brew day, I noticed that the tap water smelled like bleach and I just thought, THIS IS WRONG.

To cut a long story short, I now filter my water and the difference is HUGE. Im hitting my targets each time (both pre and post ferment) and my beers are tasting good again.

Again, I'm not sure if it's relevant to you, but its worth noting that the chlorine and chloramine levels in tap water do fluctuate considerably and even if its been ok in the past, it might not be on any given day....
Tap water in all locations is periodically 'super chlorinated' at certain times of the year as a part of the routine maintenace of the infrastructure... apparently it's always with 'acceptable' levels, but IMO if your tap water smells like bleach and tastes like swimming pool, its not acceptable.

 

[Rocker1986]

What are you measuring the gravity with? If you're using a refractometer then it needs to be corrected for the presence of alcohol.

 

[Bribie G]

What was your mash temperature? If it was around 70 then you wouldn't likely get down to below 1020.

 

[Beersnob]

I used a hydrometer to measure with Rocker. And Bribie I'm having trouble keeping my mash temp consistent. It was supposed to be 68C but after the 90 min mash it had stayed at around 70-71. Thanks Phili I didn't smell any chlorine but will certainly keep that one in mind. Timmi & tex, the yeast was fresh and at 20c when pitched. I oxygenated the wort with an aquarium pump, didn't use a yeast starter, but I think I might start doing just that in the future. I pitched one whole vile of yeast as recommended.
Tex I might try jp's suggestion adding lager yeast. I've also heard of pitching a pack of mangrove jack dry enzymes? Any thoughts on that?

Grain bill was
4.00 kg - Pale Malt (2 Row) US
0.60 kg - Caravienne Malt
0.40 kg - Caramel/Crystal Malt - 60L
0.40 kg - Caramel/Crystal Malt -120L
0.30 kg - Special B Malt
0.15 kg - Chocolate Malt


Batch Vol: 22.00 l Est OG : 1.061 SG
Fermentation Estimates
Yeast/Fermentation:
1 pkg - English Ale (White Labs WLP002)
0.60 kg - Maple Syrup - Add after boil complete (9.3%) - 69.0 EBC
Est FG: 1.018 SG

 

[manticle]

71 degrees with that amount of spec malt?

Definitely going to lead to a high fg and 1.025 -1.030 does not surprise me

Where did you get that recipe? It's a bit nuts.

1061 needs either a good size active starter, more than one pack or a pack that came from the manufacturer yesterday.

Bottling or kegging? Fast ferment test is your next best bet but I'd examine recipe formulation closely.

 

[philistine]

as mentioned by a few, by the sounds, mash temperature is your issue in this case. In a nutshell, at 70-71 degrees, you would have wound up with a lot of un-fermentable sugars especially combined with the amount of spec. malts as Manticle says.

 

[dr K]

Denaturation of the amylase enzymes is function of temperature, time and mash thickness.

 

[Tex083]

71 is high for a mash, I think some brewerys use a 70c for 30 mins mash for big body stouts.
English yeasts typically leave more unfermented sugars behind when compared to US yeasts.
Adding enzymes post boil will not achieve the FG. They will continue to convert everything (well that's what I'm lead to believe. Helps in the mash but needs to be boiled to denature)
1.030 FG would give you a ?mild/low ABV porter.

 

[Beersnob]

Well, all of you are correct, also speaking to another brewing friend last night and he agrees with you all. Too much specialty grain, and with the high mash temp, that's where I'm at. I also spoke to my home brew shop, he advised me to rock the fermenter and increase the temp a little to see if the 002 comes back out of suspension and reactivates, but 12 hours later still nothing. I found this recipe on Beersmith cloud, obviously not a great pick, I'll put it down as a lesson learned. Hopefully when it finally in the keg and carbonated it will taste ok.

 

[Danscraftbeer]

I have the opposite scenario. I've just finally realised why my beers are always finishing lower than target.
Resulting higher ABV throwing out the balance intended.
Simply an inaccurate thermometer. Now I test with 3 thermometers and get 3 different readings to my annoyance.
I take an average not really knowing what the true temp is. Frustrating.
I thought I was mashing at 66 it was more like 62 etc. 63 was more like 58!
For eg. FG's like 1.007 (Beersmith estimate - 1.012) With 7% Crystal + 9% Munick.

 

[philistine]

Best present I ever got was a Thermapen - I woudl have probably never bought myself one, but its the most accurate thing in my whole brewery

Also worth mentioning that hydrometers aren't always accurate either, mine is +0.006 out

PS. Dont stress man, if it tastes good, you win!

 

[manticle]

Well, all of you are correct, also speaking to another brewing friend last night and he agrees with you all. Too much specialty grain, and with the high mash temp, that's where I'm at. I also spoke to my home brew shop, he advised me to rock the fermenter and increase the temp a little to see if the 002 comes back out of suspension and reactivates, but 12 hours later still nothing. I found this recipe on Beersmith cloud, obviously not a great pick, I'll put it down as a lesson learned. Hopefully when it finally in the keg and carbonated it will taste ok.

Pick yourself up a copy of designing great beers and get a good handle on what processes and ingredients bring to the party.

You'll be able to spot bad recipes and design good ones.
Once there, tweaking according to palate and preference is all you'll need.

 

[Dozer71]

Simply an inaccurate thermometer. Now I test with 3 thermometers and get 3 different readings to my annoyance.
I take an average not really knowing what the true temp is. Frustrating.
I thought I was mashing at 66 it was more like 62 etc. 63 was more like 58!

You can check your thermometers with 2 known readings. The easiest is ice point and boiling water. With ice point I use an ice slurry usually from the scrapings of my old freezer. This should give you an idea on which thermometer is more accurate.

 

[Coalminer]

Remember that glass thermometers come in different immersion depths which influence their accuracy.
Usually either full immersion or 76mm immersion

 

[Zorco]

I had high FG until I discovered my actual temp reading error

http://www.aussiehomebrewer.com/index.php?/topic/91045-LessonLearnt%3A-Temperature-Probe-Connectors

Now my beers feel dry when I ferment low. Accurate thermometer! A must.

So much excellent information here. I'm going to think about water more closely again.

 

[philistine]

You can check your thermometers with 2 known readings. The easiest is ice point and boiling water. With ice point I use an ice slurry usually from the scrapings of my old freezer. This should give you an idea on which thermometer is more accurate.

Boiling point varies depending on your altitude and the atmospheric pressure on that particular day.
I was actually trying this same thing our recently to see if I my thermo was accurate and in the process learned that where I live, water boils at 98.2 degrees - not 100.
(just thought Id throw another variable in there :blink: )


If ya wanna check for yourselves and geek out on your next brew day, you can find out what your current boil point temp is with this link .
You'll just need to use a decent weather website to find out what the current pressure is and then convert it from Hpa to Hg (hectopascals to inches of mercury)

 

[Tex083]

Grab a copy of Brewing Classic Styles, I have brewed a few beers from the book and they are fantastic! The foreign extra stout is one of my favourites to brew and add stuff to like coffee or Bourbon