Sweet taste at end of fermentation

I’ve continued to try to figure out a ‘house’ flavor in some of my lighter beers and I continue to try to put more information together for this mystery taste that isn’t unpleasant and not noticeable in darker/heavier beers.

The taste is hard to define, I don’t want to use the word ‘buttery’ because its not, but it’s a sweetness taste.

I am an AG brewers, I have tried changing base malts and companies and I always make a yeast starter and pitch at .75 rate. I use servomyces for yeast nutrient. I ferment in 15.5 G sanke kegs under pressure (2-7 PSI). I hit my numbers right on at 1.048 and pitched the yeast last Sunday around 74 F. Overnight it cooled down to around 70 F. All of my temperatures are through a thermowell, so we are getting the actual internal readings. I hooked up my heating pad to ensure and made sure it never got too cold. My pressure built it right away overnight and I knew fermentation had started. I tasted the beer 3 days into fermentation and there was no off flavors and the it was right on. There was a slight sweetness to it, but I accounted that as having extra ‘sugars’ left for the yeast to continue to eat up and that would go away. I should clarify though that this sweetness taste is different than the problem I am talking about. I just took a hydro sample yesterday and it finished at 1.011 right on target and right away that ‘house’ taste is there. It consistently develops in the last phases of fermentation. I am trying at this point to give the yeast a d-rest and heating it up to 75 to see if I can get the yeast to clean up things and we’ll see. But this issue continues to haunt me.

The taste is not consistent to yeast brands or strains. It happens with US-05, Wyeast 2565, etc. No matter the recipe the same taste shows up, it all depends on how light of a beer it is for it to be noticeable.

I’m getting to the point where I’m extremely frustrated and ready to throw in the towel and sell my equipment, because I can’t make what I consider good beers or differentiate my beers.

My water is excellent for brewing and several people locally have great success with it. I have also tried RO water in the past with the same result.

I appreciate any insight people can offer.

I had the same problem early on. I've pretty much eliminated the problem over the last year.

For me fixing the problem involved:

• Controlling Mash Temps - I got a much better thermometer and really started paying attention to a few degrees during the mash. I was mashing too high in many cases.
• Adding O2 prior to pitching - Made a huge difference in my fermentations. They started sooner, were much stronger, and ran longer.
• Making Starters - I generally do a 2L for most beers. More if required.
• Aging - For most beers I age for up to 1 month in the keg after 1 month in primary. This makes a difference in my opinion.
• Water Chemistry - I'm still figuring this out. Acid Malt is almost always added in my batches now.

b-boy said:

I had the same problem early on. I've pretty much eliminated the problem over the last year.

For me fixing the problem involved:

• Controlling Mash Temps - I got a much better thermometer and really started paying attention to a few degrees during the mash. I was mashing too high in many cases.
• Adding O2 prior to pitching - Made a huge difference in my fermentations. They started sooner, were much stronger, and ran longer.
• Making Starters - I generally do a 2L for most beers. More if required.
• Aging - For most beers I age for up to 1 month in the keg after 1 month in primary. This makes a difference in my opinion.
• Water Chemistry - I'm still figuring this out. Acid Malt is almost always added in my batches now.

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(1)I built an electric brewery so my mash temperatures are right on to the degree.

(2)I forgot to add that I give my wort about a 60 second burst of pure o2 with a diffusion stone

(3)I also always make a 2L starter at a minimum

(4)Aging seems to help, but many times its a ridiculous amount. I had a lager with this taste that I was frustrated with and let it sit for 7 months, and the taste was gone.

(5)I use water chemistry tools associated with www.brewersfriend.com and add lactic acid (always under 2% of the total recipe), to get my pH to around 5.3 range.

Sounds like you've got everything pretty much covered.

I do about 1-1/2 minutes of O2 for a 6-gallon batch. I run it very low, so very few bubbles break the surface of the wort.

I re-read your post and you mention fermentation tempuratures. I have a fermentation chamber, but I generally only use it for the first 2 weeks of fermentation. I ferment pretty cold - usually around 59F for most of my ales. I use PacMan for the most part, though I've also used Nottingham on a few occasions.

After 2 weeks I move the carboy to the basement (~65F-70F) to dry hop, or until I keg. That does give my beers a few weeks at warmer tempuratures to 'clean-up'. I've never tested my wort to see if there is a noticable difference after the warm phase. I don't take any gravity readings until I'm ready to keg, so I can't comment on what happens during the warm-up period.

You really want to pitch most American ale strains at roughly 62-64F and let the fermentation take the temperature up to 66-68F. A lot of popular strains at 70F are no longer going to be "clean." My assumption is going to be the higher temperatures making your brews (especially lighter ones) seem less clean.

You mentioned Wyeast 2565 which is especially suited for cold ale temperatures (56-62F) and that's where it's going to be at it's best.

Also some hop varieties definitely add a perceived sweetness if you are making hoppy brews.

I was fermenting in the winter/spring when ambient temps in my basement were 64-65 degrees so and someone commented to me maybe that was too cold and maybe the yeast weren't cleaning things up.

Most of the brews I have made are not hoppy, when i make an IPA the taste is gone or hidden due to all the flavor the hops add. It's the lighter beers that this off flavor shows its face.

One benefit of fermenting under pressure it that is suppresses quite a few off flavors like esters from forming. I should note I have made test batches in buckets as well and the same flavor continues to plague me.

I wish there was a place I could send this beer off to that could tell me what is exactly the flavor and how to get rid of it.

When you say lighter beers are you talking about ales or lagers and are you using ale strains or lager strains. Also are you using a lot of pilsner malts?

If lagers it sounds as though your fermentation temperatures are a little high, then you need the D-rest to finish and cleanup and then you need to lager at cold temperatures for a good period of time. If you are not following good fermentation practice then it's possible that is why your lighter beers are suffering.

Otherwise it seems as though you have hit all the variables pretty well and for ales, which are more forgiving, your temps and process seem fine. I find that lagers really require good temperature control for great beer. Light beers show flaws extremely easy.

Unfortunately for me I'm talking about ales.

I've tried varying the different base malts from 2-row to pilsner as well and get similar results.

Lagers I don't recall the flavor as much.

-MG- said:

I wish there was a place I could send this beer off to that could tell me what is exactly the flavor and how to get rid of it.

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start entering your beers into competitions. the feedback those BJCP guys give is really helpful in identifying off flavors. Sometimes they will even give you homebrewing/fermentation/etc tips on how to eliminate the bad flavors. If every beer is getting knocked for a particular problematic off-flavor, then you know what is going wrong.

Or better yet... find someone local with BJCP certification and invite them over for a "sampling." Call your LHBS or email the contact for a local competition..they can probably hook you up with some BJCP judges.

jfolks said:

start entering your beers into competitions. the feedback those BJCP guys give is really helpful in identifying off flavors. Sometimes they will even give you homebrewing/fermentation/etc tips on how to eliminate the bad flavors. If every beer is getting knocked for a particular problematic off-flavor, then you know what is going wrong.

Or better yet... find someone local with BJCP certification and invite them over for a "sampling." Call your LHBS or email the contact for a local competition..they can probably hook you up with some BJCP judges.

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Thanks for the tip. I'll look into doing this. I tried including some members of my local club, but we were unable to identify the problem.

You mentioned pitching at 74 degrees. Is that typical?

Ideally, you'd pitch at 62 degrees or thereabouts, and let the temperature rise up to 66ish or so for fermentation for the cleanest yeast character and optimum yeast health.

To test that out, you could make a lighter beer and split it into two batches. Ferment one by pitching at 74, then chilling, and ferment one by chilling to pitching temperature, and then pitching and letting it free rise up to 66 degrees or so. See if that makes the difference, and I think it will.

Yooper said:

You mentioned pitching at 74 degrees. Is that typical?

Ideally, you'd pitch at 62 degrees or thereabouts, and let the temperature rise up to 66ish or so for fermentation for the cleanest yeast character and optimum yeast health.

To test that out, you could make a lighter beer and split it into two batches. Ferment one by pitching at 74, then chilling, and ferment one by chilling to pitching temperature, and then pitching and letting it free rise up to 66 degrees or so. See if that makes the difference, and I think it will.

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I bet if I look back at my brews that is probably typical for me to cool it to the mid 70s or so and then pitch the yeast. My internal probe told me initially I was at 75 F for the first few hours then it settled down.

-MG- said:

I bet if I look back at my brews that is probably typical for me to cool it to the mid 70s or so and then pitch the yeast. My internal probe told me initially I was at 75 F for the first few hours then it settled down.

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Sounds like you're fermenting a little warm. There's strain-by-strain variation, but most ale yeasts work at their most clean somewhere in the low-to-mid-60's; people who have the ability to quickly cool their wort will try and pitch even lower than that, in the high 50's, just to make sure the yeast don't throw any off flavors during the lag phase.

Now, that doesn't mean that higher temperatures won't help the yeast finish off those last couple gravity points and clean up after themselves -- but, the key is, don't go up to the low 70's until after the most active phase of fermentation is past. You want your yeast to chew through the bulk of the fermentables cleanly; once you're down to those last couple of points, they won't throw off enough esters to be noticable, so, it becomes safe to raise the temperature.

I plan to brew this weekend a similar batch to what I just made and then do a side by side comparison. My goal will be to chill down to 60-62 F and then pitch the yeast along with all my other processes.

I hope this is my issue. I would like to believe my processes are really solid and its hard to imagine what I could be missing at this point.

Like I said above. If I recall I have always pitched yeast in the mid to high 70s. My last batch I recall the temp probe in the fermenter showing 25 C (or 77 F) right after I sealed it up.

I'll post back results.

Did you ever come up with some peace on your problem here? I too have had literally the exact problem plaguing me for the last eight or so brews. The beer is "drinkable" by my standards but by no means good. They have had that "sweetness" on the finish (and on the sides of the tongue as weird as that sounds) that just seems to ruin the beer for me and make it taste not clean. It's not a gravity issue as they all finish in the sweet spot (no pun intended). I am in the same boat where I don't think it has that buttery/butterscotch taste, but it's just not right. It's always in the beers that don't have the bold hop additions or dark roasted malts. I'm glad I found this thread as I have been trying all sorts of google word combinations to find somebody with a similar problem. Like you, I always make starters and fermentation seems to go smoothly.

I'm thinking it may be something with the mash - I didn't notice this when I was mashing in the old water cooler, but after I bought a new kettle with thermometer, ball valve, and false bottom I've been doing direct fire mashes. I'm thinking maybe my temperatures are too high and I am not making enough fermentable sugars - The false bottom sits so high off of the bottom of the pot, I feel like the liquid at the bottom is getting way too hot, and thermometer isn't reflecting because it is half way up the pot in the grain bed. I do my best to recirculate, but I don't have a pump. I am thinking about going back to the water cooler and seeing how things turn out. If that doesn't work, I am going to leave the chiller in a few minutes longer and see if starting my ales in the high 50's and leaving it in the cold Cleveland winter basement helps.

Glad there is somebody to commiserate! Cheers!

Anything you gents picked up on this over the last 18 months or so?

I changed a few things and have gotten better results. I've started to leave the wort chiller in a bit longer to really get temps at pitch time below 64F. I've found that with a healthy starter the yeast has no problem getting going. I've also started hitting every batch with O2 right before I close it up. A good 3-4 week aging in the keg under carbonation has made a difference (except with the hefeweizens, I find those are best ASAP, as I think is the consensus among many beer drinkers). It usually takes me and the beer leaches (I mean friends) about 2-3 months after 3 weeks of aging to cash a homebrew keg with it tasting a bit different each week; usually for the better. I think a lot of the off flavors that were bugging me in my lighter beers were a result of it being too green. I also switched back to fermenting in buckets, don't know if this makes a difference, but it's just easier I think to handle.


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Ease up on the specialty malt. That stuff is great if used correctly, but reading some recipes, I have to question some peoples' sense of taste. I find many commercial beers of all styes too cloyingly sweet. The art is to find the balance grasshopper.