Off flavor/smell that will NOT GO AWAY. HELP!

Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum

Help Support Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Orr

Member
Joined
Jun 29, 2008
Messages
5
Reaction score
0
Hello all... new poster here. I've only been brewing for about 6 months and I've encountered an off-taste I can't seem to get rid of.

My first two batches came out fine with no off taste. The 5 or 6 since then have all had the same flaw, which is like a burnt plastic type of smell and flavor. I do mini mashes with bottled water with a 2 week primary and a 2 week secondary both in glass carboys and then bottle/keg. When racking to secondary, the smell is not yet noticeable, but when it is time to bottle, there it is.

The first time I got this flavor, I thought it was either wild yeast contamination or unclean equipment. So the next time I brewed, I cleaned all equipment thoroughly with oxyclean and sanitized with starsan (which I was doing before, but was especially attentive to this time). Also cleaned all deposits off kettle with PBW. I also cleaned all surfaces and floor of my kitchen so that that was also spotless. Flaw was still there at bottling time. Decided to switch to kegging.

The next couple times I thought maybe there was contamination in either my aqarium aeration equipment (I stupidly dunked the entire thing in sanitizer, getting the filter wet) or in my racking equipment. So I boiled the stone and bought a new filter and hose for aeration. Thought that there might be a scratch inside the siphon hose, so I bought new hose (which I upgraded to silicone hose) as well as a new auto siphon and racking cane. Also made sure to immediatley dunk in water after use and then to soak in warm oxyclean to prevent deposits from forming. Off flavor still there. :mad:

Up to this time I had not been using a yeast starter, so thought maybe underpitching was causing problems. Made a 700ml yeast starter for this batch, and pitched that. Also turned off AC so there would be no drafts at pitching time. Also turned off AC when it was time to rack. Lo and behold, the off flavor is once again there at kegging. :mad: :mad:

I honestly don't know how I could improve my cleaning/sanitation, short of a cleanroom. Wort is cooled quickly with combination ice bath and immersion chiller (which is boiled in the wort for last 10 minutes). These were all different recipes with different yeasts from a very reputable homebrew store. Yeast starters were all nice with a 1/2" of krausen. All fermentations were vigorous with quick start times and 2" krausen. None of the recipes were Belgians (save this last one which was a Belgian wit) or hefeweizens with funky yeast strains.

There are two problems that I can identify, however. The first is that the first few times I transferred the cooled wort to carboy I did it by by straining through a screen. This immediatley clogged with trub and I had to scrape it out with a sanitized spoon, which made the process take a little long, possibly exposing to airborne contamination. I then eliminated the screen and dumped trub and everything else in primary, which is probably foolish since it eliminates the gains from the hot and cold break. This next time I will do a whirlpool and then siphon to primary.

The second problem is fermentation temperature. The first two brews, which were fine, were fermented when the temperature outside was relativley cool. These fermented at about 65 degrees ambient temp. As it has warmed up they have been fermenting at a steady 73 degrees ambient temperature. I understand that inside the carboy the temp is probably higher, but is it TOO HIGH? Could too high of a ferment temp cause this off flavor?

Anyway, thanks for reading such a long post, and if you have any ideas/observations/questions I would love to hear them. Looks like a great community with a lot of knowledge!
 
Your technique sounds good. Could you describe the off flavor and smell better? Burnt plastic is kind of hard for me to place. Would you elaborate a bit more? Maybe medicinal? Burnt like burnt sugars?
What kind of extract are you using?
 
Your technique sounds good. Could you describe the off flavor and smell better? Burnt plastic is kind of hard for me to place. Would you elaborate a bit more? Maybe medicinal? Burnt like burnt sugars?
What kind of extract are you using?

The off flavor is kind of hard to describe and it doesn't really match up too well with the descriptions in my brew books. The first time it was more burnt plasticy, slightly medicinal or MAYBE electrical fire if you were really stretching it, which made me think wild yeast. The other times the burnt aspect was not really noticeable but it was still plasticy.
The best way I can describe it is if you have ever gotten a new fridge with a water dispenser and the first few times you drink out of it it has that slightly plastic taste. It is similar to that. I thought is possibly could be plastic contamination, but I replaced all the plastic (auto siphon, hose and moved to a metal racking cane) the wort came in contact with and the flavor is still there.
Not burnt sugar.
I have an electric stovetop so the boil is probably not as vigorous as it could be, but it is still a nice rolling boil.
Extract is light Liquid Malt purchased from a homebrew store that does very big volume and turns over quickly.
Also do not use any chlorine/bleach in my cleaning.
If I was forced to make a guess, I would say it is either phenolic or solvents, which is quite a wide net, I realize.
 
It sounds like your set-up is clean, my first shot would be the temperature control, depending on the yeast 75F+ might be causing some off flavours. Burnt rubber would be a new one for me though. I would use a plastic bucket swap cooler to get the fermentation to the ideal range for the yeast.
Also you may want to look into late extract additions, it may be that your wort is very thick and your scorching the malt extract. Hopefully you can get a handle on this and good luck.
 
I'm thinking temp control is the issue as well...I'm wondering does the off flavor fade with long bottle conditioning, like if it's there @ 3 weeks, has it faded after 6 weeks?

We had an unseasonable hot snap toward the end of winter, the day after I had brewed and I hadn't set up my warm weather swamp cooler setup...Well I cane home to find it 84 degrees in my place and the ferm strip reading high 70's. The beer had sort of a plasticky bubblegummy sort of flavor @ bottling, and not too much better @ 3 weeks...I'm at about 6 weeks in the bottle and it is now pretty much gone...and the beer is actually quite nice.

Not as nice as a temp controlled beer mind you, but it is drinkable.
 
If it ends up that temp isn't the issue I would try just using plain ol tap water. If you worry about the chlorine, boil ALL of it. You might be able to drive most of it out with a good boil. Clean and sanitize the fermenter and airlock first then add 2-3 gallons of the boiled tap water. Add the wort, then top it off 5 gallons with some more boiled tap water. If you say it tastes like plastic or phenol like, my first thought is all the talk of phenols leaching from plastic bottles.
 
That "hot electric" reference leads me to metallic...:confused:

I'm guessing this is not the cause.....I once dropped a very fine mesh steel screen into my wort. I decided not to fish it out. The beer smelled metallic almost tasted like blood. I never found the mesh screen. I swear it dissolved into my wort. The flavor eventually went away.

Another off flavor I've had has come from bottled water. When I top off with extracts I usually use Wal-Mart spring water (packaged in 1 gal jugs). One time I got plastic tasting water, so as a result my beer tasted like plastic. SWMBO alerted me to this since I used a partial jug. The plastic taste fades with time.

I found out that plastic water jugs stored in direct sun light have this leached plastic taste. I always remind SWMBO not to buy water on her lunch break as the sun shining into the car will ruin the water.

BTW - What kind of sanitizer are you using? - Edit: Oh Starsan.

Are you diluting properly?
 
I too had a plastic batch recently. Tasted ok up front with a strong plastic aftertast. It is like a very strong taste like water that has sat in a plastic water bottle on your bike in the hot sun for a few weeks.

What are you using for water? What type of water to you top up with? What are you sanitizing with?

My research suggests that this taste is phenols which can be caused by wild yeast. But, it can also be caused by Chlorine. Perhaps unboiled tap water or failing to fully rinse clorox from equipment? The batch I had was an all grain batch of cream ale. After boiling off too much i (stupidly) topped off with cold tap water. I think that may have been it.

Good luck.
 
I would use a plastic bucket swap cooler to get the fermentation to the ideal range for the yeast.
Also you may want to look into late extract additions, it may be that your wort is very thick and your scorching the malt extract.

I've actually been adding only a portion of the extract at the start, and the remainder with about 15 minutes left. I think Palmer mentioned it in How To Brew. How does this plastic bucket swamp cooler work?

Revvy said:
I'm wondering does the off flavor fade with long bottle conditioning, like if it's there @ 3 weeks, has it faded after 6 weeks?
Funny that you should say this. After Yooperbrew asked me to better explain the off taste I cracked open a bottle from the first batch. The taste is still there, but definitely not as intense. These are about 12 weeks old, however.

Skrimpy said:
If it ends up that temp isn't the issue I would try just using plain ol tap water.
I should probably try this... at the least it is another variable to get a handle on.

homebrewer_99 said:
That "hot electric" reference leads me to metallic...
Doesn't really taste metallic at all to me. Definitely more toward the plasticy end of things

Schlenkerla said:
Another off flavor I've had has come from bottled water.
I think I will try just using boiled tap water. Never really thought about the bottled water leaching off tastes.

Schlenkerla said:
Are you diluting properly?
I assume so. I bring 2.5 gallons to 160, do my mash, sparge with 1 quart per 2lbs of grain, and then when done with my boil add enough water in the fermenter to equal 5 gallons. I measure the gallonage with a marked stick.

Matt Foley said:
What are you using for water? What type of water to you top up with? What are you sanitizing with?
It's Primo Water in a 5 gallon jug, sometimes Ozarka in 1 gallon. StarSan for sanitizer. Top up with more bottled water. I'll give boiled tap water a shot next time.

Seems like the consensus so far is possible leached taste from bottle water and too high fermentation temps. I guess I should buy a stick on thermometer for they carboy to see exactly how hot it is. What can I do short of buying an extra fridge to keep temps in the their ideal range?
 
Actually, there is no benefit of boiled tap water over bottled water its just that unboiled tap water with have some chlorine. I have just purchased a charcoal filter to see if that works better with tap water. In any event, you may try to switch up your water source and see if it helps.
 
Actually, there is no benefit of boiled tap water over bottled water its just that unboiled tap water with have some chlorine. I have just purchased a charcoal filter to see if that works better with tap water. In any event, you may try to switch up your water source and see if it helps.

+1

My tap water doesn't taste very good, so I used to buy a lot of bottled water. For the sake of my wallet and the environment though I went out and got a charcoal filter. The water taste fine now and so far I've made some very good beer with it. I bought the one that attaches right to the faucet. Try it, see what happens.
 
I have had a similar taste to my last few batches. I ran it over to my local store and they suggested that I use bottled spring water due to chlorine in our local water. That or either fill a bucket up with water and cover it with a towel for several days to let the excess gas escape from the water. I just use bottled water in my two batches going right now and so far the lingering flavor has disappeared.

I did discover as well that while cleaning out my primary this weekend getting it ready for a new brew I used my Oxyclean as usual and while rinsing there was the same smell. I did a much better rinse this time and it disappeared. Perhaps a bit of cleaner left in bottles or bucket may have caused it.

In any case, bottled water and better rinsing made everything much better.
 
Bring a bottle to an experienced brewer or bring a sample to your LHBS. I have found that super experienced brewers will instantly know when they taste it.
 
Burnt plastic sounds to me like a combination of phenolic flavours and some higher alcohols (solventy and/or hot alcohol). If you are fermenting to warm, especially if you also underpitch your yeast and/or don't oxygenate/aerate fully, you can get this taste (particularly in higher gravity brews).

The other option is a wild yeast infection, which has been stated already. If this is the cause, expect your beers to worsen each week after bottling (to a point, anyways). They should also taste very thin with little head retention. Unfortunately, if you have a full-blown wild yeast infection in your equipment, you may have to chuck all your plastic equipment that can't be heat sanitized. (Ask me how I know!)
 
What can I do short of buying an extra fridge to keep temps in the their ideal range?

I use a 32-gal trash can to contain the fermenter, dump in 5-6 gallons of cool water, and add ice to maintain the temp. The temp swings a bit of course, but it's far better than I did without, esp. since the yeast often heat things up a bit during a vigorous fermentation. If you can, the bathtub also works nicely.

- Eric
 
I use a 32-gal trash can to contain the fermenter, dump in 5-6 gallons of cool water, and add ice to maintain the temp. The temp swings a bit of course, but it's far better than I did without, esp. since the yeast often heat things up a bit during a vigorous fermentation. If you can, the bathtub also works nicely.

- Eric

You can only get in one fermenter, right? It sounds like a great idea for just one...This is what I use for 2.

brewcloset1.jpg


It's a rubbermade bin, I have an aquarium thermometer stuck on the side of it in the water and I use frozen 2 liter and smaller bottles of water to chill the water in the bin. Adding a fan blowing on the t-shirts will help lower the ferm temps even further...I can get my fermenters down into the low 60's in my loft this way.
 
To me it sounds like people have had varying results with bottled water, tap water etc. Tap water has worked fine in my brews but right now I am only brewing extract and I have heard the water doesn't matter as much. From what it sounds like to me is either your plastic is leaching into the fermenter, or wild yeast produces phenols in the beer (which I didn't know...you learn something every day).
 
Sounds like oxidation. I had a fermenter that wasn't completely air tight and while I never had a problem with infections the beers from it always had off flavors in them with plasticy (among other things) in there, but never bad enough not to drink.
 
Wow, lots of great ideas/suggestions here. Placing the fermenters in a cool water bath looks like it will help out until I can find a cheap fridge on Craigslist. Thanks everyone!


:mug:
 
The other option is a wild yeast infection, which has been stated already. If this is the cause, expect your beers to worsen each week after bottling (to a point, anyways). They should also taste very thin with little head retention. Unfortunately, if you have a full-blown wild yeast infection in your equipment, you may have to chuck all your plastic equipment that can't be heat sanitized. (Ask me how I know!)

I've recently completed a couple of brews where it appears wild yeast has taken over. My LHBS diagnosed the worse of the two as a result of wild yeast. I have a third batch finishing up and will bottle this coming weekend.

Assuming I have the wild yeast problem and if this third batch appears to comfirm the continuing problem... I'm very interested in your comment concerning "pitching the plastic". Could you help me out with a little more detail on this?

Thanks...
 
Assuming I have the wild yeast problem and if this third batch appears to comfirm the continuing problem... I'm very interested in your comment concerning "pitching the plastic". Could you help me out with a little more detail on this?
Unfortunately, if the wild yeast infection gets into your fermenting equipment or racking equipment, it can be hard to clean out. Chemical sanitizers often won't rid them because microscopic scratches in plastic can harbour the spores of the yeast. Heat sterilization is necessary (but obviously, is problematic for plastic).

If you think you picked up the bug during infection, I would replace any plastic buckets, rubber/plastic bungs and blow-off tubes. I would also replace all your racking hoses, just in case. If you are CERTAIN it is a wild yeast contamination, you pretty much have to replace all the equipment at once because you can't be sure which pieces are contaminated. If you throw out some things, but not others, there is always a chance that one remaining contaminated piece will infect the next brew (and possibly the new pieces of equipment). I lost 3 or 4 batches of beer trying to figure out my source of infection, and never did -- I only solved things by chucking all my plastic. I wish I had just done that from the beginning and saved some batches of beer and much frustration.
 
What is your process of transferring from primary to bottling bucket? I think that is where your problem is (just answered the same question elsewhere).

Is your bucket high enough so the siphon tube reaches all the way to the bottom, eliminating any splashing about? Do you keep a cover on your bucket?

I think aeration is the problem again, AFTER the beer has been fermented.
 
My experience with electric heat in cooking has nearly always produced some level of carmelization at high heat. Burnt sugar can smell plasticy. I would burn a little extract in a pan compare the smells.

What kind of extract are you using and how is it shipped/stored by you and the seller?

The observations on water containers in the the thread look like another likely place to look.
 
Hmnnnn....What kind of hops are you using? I recently made a pale ale with summitt and crystal hops, and it never really came out right. It has a great flavor up front, but an almost medicinal aftertaste that I'm convinced came from the hops combination.
 
Orr, did you ever fix the problem you were having? I'm having the same exact problems and tastes!! i used tap water and bottled water and i have the same results. Extract and All-grain batches too! I've been told it's Chlorine from my tap water, but my last batch I used bottled except for the priming(which was stupid) I boiled 1cup of tap water with corn sugar. Not sure if 1 cup of tap water can make such a bad platic chemical aroma and flavor.
 
I'm pretty sure that this particular problem doesnt have anything to do with Temperatures though. I'm narrowing it down to either A. Bacterial Infection or B. Bad water(Chlorine). There is absolutey nothing wrong with our technique thats for sure, becuase I brewed an All-grain DunkelWeizen (boiled outside In a thunder storm mind you) at a friends house using some of my equipment. Only difference was that we used his PA well water which ran through a filter ooposed to my treated NYcity water. This was his first beer and it came out flawless and ive made 6 batches prior to that one so go figure........
 
I have had about six batches go bad due to this same "burnt rubber" taste/aroma. I notice they both get stronger the closer to the yeast. Also, the yeast looks weird during primary, it gets these little "balls" about the size of bb's. I have done all the things Orr mentioned. Replaced gear, focused on sanitation, used starters, worried about chlorine, over rinsed, watched ferm temps closer, used new vials of yeast, re-pitches. I had two batches turn out drinkable the difference in them was I used US-05. My latest conclusion is, that my yeast was degrading due to high storage temp. I keep it in my lager fridge at what used to be about 50 degrees. The only reference I could find to "burnt rubber" taste was in Noonan's book and he said it was yeast degradation. A friend keeps trying to point me in the direction of autolysis, but my last batch went bad in about 9 days, and I racked it to secondary at day 7. I am at a total lose here. I thought I had found the problem when I discovered my Star San was expired by two years. But new Star San didn't help. I even switched to Iodaphor for a bit. I do sometimes notice I get the same flavor in coffee. I thing I read recently stated this flavor is generally confused with acidity. I thought perhaps my hard water was throwing my PH way off. But it sounds like bottled h2o won't get my better results.

Any suggestions welcome.

Thanks.
 
Electrical fire would point to wild yeast infection, if it is more plastic and medicinal it is probably chlorine is your water, do you use tap water if so get some test strips.
 
I have had about six batches go bad due to this same "burnt rubber" taste/aroma. I notice they both get stronger the closer to the yeast. Also, the yeast looks weird during primary, it gets these little "balls" about the size of bb's. I have done all the things Orr mentioned. Replaced gear, focused on sanitation, used starters, worried about chlorine, over rinsed, watched ferm temps closer, used new vials of yeast, re-pitches. I had two batches turn out drinkable the difference in them was I used US-05. My latest conclusion is, that my yeast was degrading due to high storage temp. I keep it in my lager fridge at what used to be about 50 degrees. The only reference I could find to "burnt rubber" taste was in Noonan's book and he said it was yeast degradation. A friend keeps trying to point me in the direction of autolysis, but my last batch went bad in about 9 days, and I racked it to secondary at day 7. I am at a total lose here.

Thanks.
I swear that I have this exact same issue. There is a strong rancid rubbery off smell/flavor that gets much worse the closer you get to the yeast. I've only ever had this problem in batches where I use english yeast, filtered tap water (with campden for chlorine) and keep the beer in the primary for 2+ weeks. I usually swirl up the trub when I'm cleaning to make it easier to pour out, and if I smell the result, it's really quite awful.

I'm really leaning towards autolysis but I see stuff all over the web about it being a big myth. Part of me is starting to wonder if it's some kind of reaction between the yeast and something in my city's water. I do full boils, so I don't add back any tap water that could be causing the issue.

I just did a pumpkin ale using London ESB yeast and spring water, so that will likely be the true test. As much as I hate spending $10/batch on spring water, I haven't had a bad batch yet when I've used it.
 
I've had same exact issue. "Burnt eletrical wires" smell and a strong plastic taste on a few batches in the past. They were never consecutive batches, just 2 or 3 times over a 8-10 batch period. This led me to believe it wasn't a equipment or procedure (cleaning/ snaitizing) problem. However, I did change plastic tubing (they are cheap and why take the risk). After a bit of research, I narrowed it down to POSSIBLE chlorophenols or chloromines or whatever the hell they're called. These are present in your tap water to some varying degree or another. At most times my water supply (NYC) is fine, but during the summer months, more chlorine is present in the water. I started using Campden Tablets (1/4 a tablet per 5 gallons) (or use potassium metabisulfate-it's the same thing but in powder format not tablet). Put you water in a bucket, crush the tab/ desired amount and let it sit (some say overnight, i just give it a few minutes to an hour). I have not had the problem since i started doing this, and I've made alot of batches in the summer. Maybe it's just dumb luck. But eithr way, no problems with plastic smells/taste since
 
In reading up on this issue, it seems I have come across a lot of people in NYC with a similar problem. Glad the Campden Tablets are working.
 
Reading this thread again, I am noticing the same things most people have to. I have looked at alot of variables but I want to ask everyone which yeast strain they are using when the taste comes up. I am personally using US-05. Thanks!
 
I've been brewing for a few years now with never a batch going "bad", but I recently did a strong ale (using US-05) and had this strange smell/taste. In mine, it almost has the smell and taste of water that comes from a garden hose. After ruling out the most likely causes for phenolic off-flavors, I'm fairly convinced it was the yeast. I've used US-05 a few times before with no issues, but with this batch, it had an unusual lag period followed by a slower and less aggressive ferment. I maintained a stable temp of 68F. It took several more days for it to complete than usual, and it also did not attenuate as fully as it usually does (by a long shot, not just a few percentage points). I didn't check the date on the package (now long gone), but I'm wondering if it was either woefully outdated (very low viability) or if it was contaminated. My only hope is that somehow a long aging will help this beer. This might be my first bad batch... Sad...

EDIT: After a couple of weeks of cold storage, it seems like this flavor and smell is diminishing more and more. This leads me to believe it was definitely the yeast, as I don't believe chlorophenols from chlorinated water (which seem similar to this band-aid effect) for example ever go away. Someone correct me if I've misspoken though. Cheers!
 
I think it's the water.I had similar issues a few times and tracked it down to my undersink water filter. I now use a solid block carbon filter for my brewing, rinsing and sanitizing water. I replace the filter cartridge regularly. I also mix my star san with the same filtered water. These measures have solved my problem. Good luck to you other guys with your off-flavor problems.
 
Back
Top