Why are none of my beers finishing fermentation?

blkandrust · 07-30-2010, 02:32 AM

The last 7 or 8 batches that I have brewed have all stopped fermenting early and wound up way to sweet...from 1.024-1.035....I have been brewing for 8 years on and off..started having this prob last year.At first I blamed it on ferm temp.I corrected that.Then realized that I started having this prob after recieving a new thermometer after my other broke.Bought another floating therm today to do a side by side.Both read the same from a range of 34f to 160f..I have started eliminating variables that I considered the culprit,the last few batches,to no avail.I'm an all grain brewer that has made awesome beer consistently for years.This is making me crazy

I'm mashing at 150 for 60 min.mash out 160-165 for 15 min.batch sparge at 160.boil for 60.ferment with wyeast 1099 at 70f or 1056 at 65f.I use starters for all my beer and aerate well..Ferm starts off within hours and goes strong for a week or so then stalls.Nothing has changed in my process over the years,other than my beer not finishing..

TimBrewz · 07-30-2010, 02:45 AM

Wow, I think you have covered all the likely culprits. My brewing buddy was having the same issues lately and we think its his mash temps (off calibration thermometer)being too high). With your case, being an experienced brewer I can only assume you are using a modest amount of non-fermentables i.e. crystal malts that would raise your FG.

I know this is potentially obvious one, but have you calibrated your hydrometer?

Wish I could troubleshoot more for you, perhaps others will be able to help.

**schweaty** · 07-30-2010, 02:53 AM

Have you tried ramping up your temperature as fermentation slows down? Perhaps agitate the carboy by gently rocking it to put the yeast back in suspension. It sounds like you've been very thurough and I'm suprised you haven't nailed the problem down yet. Mashing at 150 should give you quite the fermentable wort.

**weirdboy** · 07-30-2010, 02:55 AM

I think it's mash temp. You are probably mashing too high without realizing it.

I had this problem before and finally realized that my thermometer was consistently reading over 10 degrees higher than it should have at that range. I got a Thermapen and have had consistently good results since.

blkandrust · 07-30-2010, 03:01 AM

Quote:

Originally Posted by TimBrewz

Wow, I think you have covered all the likely culprits. My brewing buddy was having the same issues lately and we think its his mash temps (off calibration thermometer)being too high). With your case, being an experienced brewer I can only assume you are using a modest amount of non-fermentables i.e. crystal malts that would raise your FG.

I know this is potentially obvious one, but have you calibrated your hydrometer?

Wish I could troubleshoot more for you, perhaps others will be able to help.

Yes,i'm only using .5# of crystal in each batch.I have calibrated my refrac several times..

blkandrust · 07-30-2010, 03:05 AM

Quote:

Originally Posted by schweaty

Have you tried ramping up your temperature as fermentation slows down? Perhaps agitate the carboy by gently rocking it to put the yeast back in suspension. It sounds like you've been very thurough and I'm suprised you haven't nailed the problem down yet. Mashing at 150 should give you quite the fermentable wort.

I have indeed tried what you suggested.I have a DFH90 clone and a house IPA that are stuck at 1.035 and 1.024 respectively..I've repitched yeast starters to each of them twice.I've added amylase a week ago.I brewed another house ipa 2 weeks ago that started at 1.059,that has nowbeen at 1.024 for 5 days..I'm going to try a digital therm as temps may be an issue..Gonna use a type k probe with a thermowell.This is soooo frustrating.Thank you all for your quick replies..

**schweaty** · 07-30-2010, 03:35 AM

I have a Johnson Control and a thermowell for my fermentation chamber and they were bar none the best investment I made. Being able to control your temps accurately has had a great effect on my beer more so than anything else I've ever added to the brewery.

Also, as another member suggested, it could be mash temp. I use four different types of thermometers on brew days just to cross reference with the others. You can never have too many readings if you're trying to be on the safe side.

prosper · 07-30-2010, 04:58 AM

what size starter are you using? Some of the older brewing materials suggest 1 pint starters, but more recently it's been determined that starters really ought to be 1qt or more to really have any sort of effect.

EBloom97 · 07-30-2010, 05:05 AM

Quote:

Originally Posted by blkandrust

Yes,i'm only using .5# of crystal in each batch.I have calibrated my refrac several times..

Let me ask you a stupid question because you just set off a red flag for me. Does the beer taste sweet or does it taste normal?

I had this exact same problem recently, and it "started" when I bought a refractometer. I was beating my head against the wall trying to figure out what was going on and I finally got it sorted. It turns out that refractometers do not read accurately in the presence of alcohol. My beer was fine all along, and it was just the tool that is flawed.

**Shooter** · 07-30-2010, 05:25 AM

Quote:

Originally Posted by EBloom97

Let me ask you a stupid question because you just set off a red flag for me. Does the beer taste sweet or does it taste normal?

I had this exact same problem recently, and it "started" when I bought a refractometer. I was beating my head against the wall trying to figure out what was going on and I finally got it sorted. It turns out that refractometers do not read accurately in the presence of alcohol. My beer was fine all along, and it was just the tool that is flawed.

Okay, this is a fair point, but the tool isn't flawed. You just have to be aware of the issue. If you want to use a refractometer for post fermentation gravity readings you have to use a formula to adjust the reading to account for the alcohol in the sample. I take final gravity samples all the time with a refractometer.