Why are none of my beers finishing fermentation?

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 crazyI'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..

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.

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 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.

TimBrewz said:

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.

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

schweaty said:

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.

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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..

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.

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.

blkandrust said:

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

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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.

EBloom97 said:

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.

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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.

EBloom97 said:

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.

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The beer tastes sweet...to sweet to drink,actually.I am unaware of the formula that is needed when taking FG readings with a refrac.How do I do this?I have tried starters of various sizes in hopes that was the problem.Anywhere from a pint to over a liter.

Shooter said:

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.

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Beersmith has a conversion tool for this. Actually Beersmith has quite a few conversion tools that are great. I prefer to use the refractometer rather than hydrometer because you only need a few drops rather than a cup.

blkandrust said:

The beer tastes sweet...to sweet to drink,actually.I am unaware of the formula that is needed when taking FG readings with a refrac.How do I do this?I have tried starters of various sizes in hopes that was the problem.Anywhere from a pint to over a liter.

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If you mashed too high then you'd have a lot of unfermentable sugars left in the beer and those are not that sweet. You'd have too much body/mouthfeel but it wouldn't really be too sweet.

If the yeast didn't 'finish the job' then you'd have a lot of fermentable sugars left in the beer and those are sweet. So if the beer tastes really sweet thern it's prob the yeast not finishing the job.

Since you said you make starters and aerate well and have been doing this for so long then it seems those aren't the problem. But something must have changed. What could possibly have changed?

What water do you use? Is it possible your tap water switched to chloramine instead of just chlorine?

blkandrust said:

I am unaware of the formula that is needed when taking FG readings with a refrac.

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So you've been using a refractometer for eight years and your beer has been fermenting down near 1.010? If so, then you do definitely have a problem with your process/fermentation. However, as others have pointed out, a refractometer cannot be direct read once there is alcohol in the mix. I know there are conversion formulas and a tool in Beersmith, but I have never had good success with it when I have compared actual hydrometer readings. I say you should at least take a hydrometer reading and be sure. The mind is a powerful thing, and your beer may be tasting sweet just because you think it is...

If you do want to try using the refractometer there is a spreadsheet at Morebeer.com that can make the conversion for you.

EBloom97 said:

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.

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If you know the OG you can accurately derive the fermenting or final gravity using a refractometer. Plenty of calculators around the webtubez to do it, too.

blkandrust: Have you checked FG with a hydrometer?

DNW said:

I know there are conversion formulas and a tool in Beersmith, but I have never had good success with it when I have compared actual hydrometer readings.

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DNW, if you still have the data from those readings, would you mind taking a look at this? http://seanterrill.com/2010/07/20/toward-a-better-refractometer-correlation/

DNW said:

So you've been using a refractometer for eight years and your beer has been fermenting down near 1.010? If so, then you do definitely have a problem with your process/fermentation. However, as others have pointed out, a refractometer cannot be direct read once there is alcohol in the mix. I know there are conversion formulas and a tool in Beersmith, but I have never had good success with it when I have compared actual hydrometer readings. I say you should at least take a hydrometer reading and be sure. The mind is a powerful thing, and your beer may be tasting sweet just because you think it is...

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I have only been using a refrac for a few months..I was unaware that refracs cannot be direct read once alchohol is involved..

I'm brewing with well water.The same that ive been using from the beginning.I have not taken a hydro reading as ive been using my refrac.It has been brought to my attention that a refrac will not be accurate once there is alchohol involved.I am going to take a hydro reading and try the conversion formula for the refrac.Thanks a ton fella's for your replies.This site rules

Yeah, I suspect that once you take a hydro reading you'll find it's quite a bit lower.

UPDATE!!!!.Well,I used Morebeers converter and it showed my DFH 90 and my house IPA both to be at 1.000!!!!!!!!!!!That would make my DFH 10.7%abv and my house IPA 7.5%!!!!.Obviously higher than anticipated.So I took a hydro reading and low and behold,they are both at about 1.000!!!!I blame this on the Amylase Enzyme i added a week ago.Sampled both and they were a little thin as you can imagine,but a lot more tolerable than the prvious few batches which I think may have stalled due to ferm temp.I also checked my other IPA that is in the ferm chamber in primary,where its been for 12 days,refrac showed it stuck at 1.024.I did a hydro and its at 1.010!!!!!!!!I was totally unaware of refracs not reading correctly if alchohol is present..THANKS A TON GUYS!!I'm getting ready to keg my DFH90 and my IPA..I wish I could have all of you over for a few pints of thin bodied high alchohol brews!!.lol..Thanks again..

You could throw a few ounces of maltodextrin in at bottling to try and beef up the mouthfeel. When I got my refractometer I was aware of this problem and it still caught me off guard at first. I took a reading and got 1.027 and wondered what went wrong. It took a couple of minutes for me to remember that I had to convert the number.

Shooter said:

You could throw a few ounces of maltodextrin in at bottling to try and beef up the mouthfeel. When I got my refractometer I was aware of this problem and it still caught me off guard at first. I took a reading and got 1.027 and wondered what went wrong. It took a couple of minutes for me to remember that I had to convert the number.

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Thats a great idea.I have some malto on hand..I already kegged my DFH90 clone,but I can still add some to my IPA..Thanks bro..:rockin:

So how do we explain the sweet taste? Is that a misinterpretation of alcohol flavors?

Right now I'm glad I still haven't pulled the trigger on the refractometer purchase.

ksbrain said:

So how do we explain the sweet taste? Is that a misinterpretation of alcohol flavors?

Right now I'm glad I still haven't pulled the trigger on the refractometer purchase.

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The 3 previous batches were way to sweet due to what I believe was low ferm temp as I had them in my garage in ferm chamber.Temps dropped for 3 days.I believe that caused yeast to crash.Didnt take any readings as I was waiting on my new refrac.Next 3 batches I brewed I didnt taste but took readings with my new refrac and all appeared to be stuck due to improper read.They obviously were not stuck.Between the previous 3 batches being really sweet and misreading my refrac I assumed I was in a disaster zone.When actually the prob was that I didnt fully understand my refrac.

I read the heading, and instantly knew what was wrong. You weren't making a starter, and or your mash temperatures were much too high.
Then I read your original post. You addressed both of those points, and taught me a lesson about jumping to conclusions.
Then I read about you using a refractometer to get the FG. That made a lot of sense.
I've found that a refractometer is excellent for getting the OG of a brew, but have yet to find a calculator that gives accurate results after fermentation has started.
I use the refractometer for the OG, but use a finishing hydrometer for the FG readings.

-a.

Lol.Had I known about the refrac not being accurate for FG readings it would have saved a bunch of worrying.Oh well,live and learn.I used this calculator and it was really close to my hydro reading. http://www.onebeer.net/refractometer.shtml ..BTW,I noticed you are from L.I..I will be up there in a couple weeks,are there any decent LHBS in Suffolk?

I've only used 2 HBS on the Island.
Karps in East Northport. http://www.homebrewshop.com/
They have the best prices, (especially with bulk grain), but not a very large selection. The in store prices also don't always match the web site, and their liquid yeast (propagator packs) is ancient.
Arbor Wine and Beermaking in Islip http://www.arborwine.com/
They have a bit better selection, but their prices are much higher.

There are others (according to google), but I have never used them.

-a.

ksbrain said:

So how do we explain the sweet taste?.

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The placebo effect.