Author Topic: plastic/mold taste  (Read 1223 times)

Offline jrhomebrewing

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plastic/mold taste
« on: December 15, 2016, 05:54:17 AM »
I have never got a plastic or mold taste in a beer until recently. I always make a yeast starter with light DME i just put it in a bottle and shake it once in a while. I mash and 152 for 90 mins usually and sparge with 170 degrees water for about an hr. then i boil for 90. cool to around 50 pitch the yeast and let ferment for a week and transfer to a second fermenter. for 2 weeks. I am wondering if its something I'm doing wrong or what are some things to try? I never had this problem until just the last few batches. It is really discouraging and makes you not want to brew again. I mostly keg beer and I sanitize like crazy. I am stumped on whats going on and need some help!!


Offline natebrews

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Re: plastic/mold taste
« Reply #1 on: December 15, 2016, 12:20:32 PM »
Are you using city water that contains chlorine or chloramine?  If so, that might be your problem.  You can eliminate it by adding some crushed up campden tablet to your water before you use it ( 1 tab is more than enough for all your water).

That would be the first place I would guess you might be getting plastic flavors.  If you don't have city water, and aren't cleaning with bleach, then it clearly isn't that.
Risk of failure should be no deterrent to trying.

Offline brewinhard

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Re: plastic/mold taste
« Reply #2 on: December 15, 2016, 03:50:15 PM »
If you are getting a plasticy/moldy taste/aroma, you may want to look at your yeast handling too. You might be introducing a wild yeast infection which could lead to these off-flavors (or some of them). How many batches has this occurred in recently for you?
When was the last time you swapped out your old siphon hoses and transfer lines? Do you keg or bottle?

Offline natebrews

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Re: plastic/mold taste
« Reply #3 on: December 15, 2016, 05:19:08 PM »
Another thing to consider is if you are filling from a garden hose.  I think it was the recent Experimental Brewing podcast that they were talking about plastic flavors coming from people using garden hoses (the green kind) to fill their brew pot with water.
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Offline PORTERHAUS

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Re: plastic/mold taste
« Reply #4 on: December 15, 2016, 05:35:29 PM »
How are you serving the beer? Could it be from old or dirty beer lines, fittings, fuacets?

Offline GS

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Re: plastic/mold taste
« Reply #5 on: December 16, 2016, 12:49:04 AM »
It does sound like an infection. Double check your sanitation process to be sure.

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Offline jrhomebrewing

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Re: plastic/mold taste
« Reply #6 on: December 16, 2016, 08:52:29 AM »
I am not using city water and dont fill my pots up with a garden hose. I have rinsed them out with one before. I think I am pretty careful about sanitizing. I use CMC to clean everything and then star san to sanitize. Its been about the last 5 batches iv made that has this flavor. I keg and bottle both. I have probably used the siphon 15 times. I am very thrall about cleaning and sanitizing i believe I do both before and after. I was wondering if I cold ever come from the hoses or the fermenting buckets? Also when making a yeast starter I always have just used a glass jug and tinfoil but again with that i always spray the tinfoil and clean everything really well that always worked for me in the past. But maybe its the yeast starter. I keep a spray bottle of star san mixed up maybe its not good anymore?

Offline natebrews

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Re: plastic/mold taste
« Reply #7 on: December 16, 2016, 11:08:04 AM »
I think I would be leaning toward the hoses and bucket being the issue.  I've never used buckets, so I don't know how often they go bad.  As far as hoses, I have been using the same hoses for a couple years now but will probably replace them before too long.  The previous one I had for 3 years and never had a problem with it.

For you starters, are you boiling up some DME/LME and putting it in the clean/sanitized glass jug with a funnel?  I did exactly that for a long time before I got my stir plate stuff, so now I boil right in the Erlenmeyer flask.  Also, do you taste your starters before you use them?  I generally get a little bit out and try it before I pour it in the beer just to make sure it is happy (usually just some of the spent wort that I'm decanting anyway).
Risk of failure should be no deterrent to trying.

Offline jrhomebrewing

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Re: plastic/mold taste
« Reply #8 on: December 16, 2016, 03:55:53 PM »
yes i do boiling up some DME/LME and put it in the clean/sanitized glass jug with a funnel. I use 2 cups water 1/2 cut DME and boil for 10 mins a cool. I have never tasted the starter before i add the yeas. a stir plate is on the list to buy someday.

The buckets i have are getting older and I have used them for lots of batches. I would like to get some glass some someday too. This last batch I brewed I soaked the bucket for about 5 HRs in CMC and washed really good and than star saned. Hopefully that helps with the taste.

As far as the garden hose I just rinsed the mash tun out with the hose and then cleaned it with the tap water.

Offline brewinhard

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Re: plastic/mold taste
« Reply #9 on: December 16, 2016, 06:59:27 PM »
When making starters you should use RO or distilled water. Or at least any water that does not have chlorine or chloramines in there. 

I still think its either your tubing or old buckets. But most likely leaning towards a wild yeast infection. They can be stubborn.

Offline ynotbrusum

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Re: plastic/mold taste
« Reply #10 on: December 16, 2016, 08:38:38 PM »
It could be mold, which is not killed by Star San, but is killed by Iodophor...once the mold is in there, a single spore can wreak havoc over time (even at pretty cold temperatures).
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Offline klickitat jim

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Re: plastic/mold taste
« Reply #11 on: December 17, 2016, 11:04:13 PM »
I used to get the occasional "medicinally plasticy" flavor/aroma in my kegged beers and determined it was an infection. I have since switched to iodophor for sanitizing kegs. And I leave it in until keeping day and sanitize my racking gear with it before dumping. I have not had that problem since

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Offline bierview

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Re: plastic/mold taste
« Reply #12 on: December 19, 2016, 09:35:03 AM »
yes i do boiling up some DME/LME and put it in the clean/sanitized glass jug with a funnel. I use 2 cups water 1/2 cut DME and boil for 10 mins a cool. I have never tasted the starter before i add the yeas. a stir plate is on the list to buy someday.

The buckets i have are getting older and I have used them for lots of batches. I would like to get some glass some someday too. This last batch I brewed I soaked the bucket for about 5 HRs in CMC and washed really good and than star saned. Hopefully that helps with the taste.

As far as the garden hose I just rinsed the mash tun out with the hose and then cleaned it with the tap water.

I don't use DME anymore for starters.  When I finish a brew, there is always some wort left at the bottom of the pot.  I pour it off, let it settle then decant the clear wort into pint or qt. containers and freeze.  When I need to make a starter I take one out of the freezer, boil & cool.  Saves money on DME and you know exactly what your gravity is from the saved wort.  If it's too high, then you would need to add some water.

Offline jrhomebrewing

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Re: plastic/mold taste
« Reply #13 on: December 20, 2016, 03:16:34 AM »
thank you for the suggestions. Ill mess around with a few things and see if anything helps. If i find a solution and if anyone is interested i can share!

Offline klickitat jim

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Re: plastic/mold taste
« Reply #14 on: December 20, 2016, 07:04:27 AM »
thank you for the suggestions. Ill mess around with a few things and see if anything helps. If i find a solution and if anyone is interested i can share!
Always interested