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General Category => All Grain Brewing => Topic started by: pagansaint on June 08, 2010, 08:55:38 pm

Title: Plastic off taste in beer
Post by: pagansaint on June 08, 2010, 08:55:38 pm
I just kegged a batch of pale ale and noticed a plastic off flavor. I read up on it and it sounds like it's phenolic contamination. I was wondering if any one else has encountered this and what it turned out to be traced back to?
Title: Re: Plastic off taste in beer
Post by: babalu87 on June 09, 2010, 05:11:17 am
What was the temperature of the beer during fermentation?
Was the yeast fresh and how much did you pitch?
Title: Re: Plastic off taste in beer
Post by: pagansaint on June 09, 2010, 06:28:43 am
The temperature in the thermostatically controlled chest freezer was 69 deg, the actual temp of fermentation a couple degrees higher. the yeast was WLP 001 which should not produce that characteristic and I pitched approximately 750ml starter which sat in the same climate controlled enviroment the prior 48 hours. Lag time was about 10 hours though. I did encounter a problem cooling wort enough though before pitching, pitching temp appx 78 degrees. I assume that is was not water since I used bottled so no chlorine in the mineral profile.No chlorine based sanatizer I use Star san, Mash procedure remins the same no changes there , Yeast ok. which basically only leaves me contmination. I figured it has to be in the tail end of the brewing procedure from boil kettle to fermenter so I threw away the old transfer tubes and bung and completely disassembled the stainleess steel valve and fittings. I usually boil the whole valve set up every couple times but after disassembling it and finding the nsaty crap in the threads and tape I think this will be an every brew procedure. Hopefully this is it. Also planned on keeping 20 pounds of ice on hand just in case I cant get my pitching temp down to 64degrees where I like it. Will also turn down the thermostat to 67 Hopefully one of these things was the problem and will have been remedied by my next brew session this weekend. It's been eating at me all week.
Title: Re: Plastic off taste in beer
Post by: babalu87 on June 09, 2010, 06:50:06 am
Quote
, pitching temp appx 78 degrees

So it could have been as high as 80.
Thats pretty high and might give you an off flavor.
Title: Re: Plastic off taste in beer
Post by: bonjour on June 09, 2010, 10:13:07 am
Quote
, pitching temp appx 78 degrees

So it could have been as high as 80.
Thats pretty high and might give you an off flavor.
+1
IMHO for most beer styles that is way to warm.  It is the early stages of fermentation that frequently lead to off flavors so pitch low and let the wort warm up to fermentation temps,  at least pitch at fermentation tem and manage to keep the wort temp there

Fred
Title: Re: Plastic off taste in beer
Post by: pagansaint on June 09, 2010, 08:55:07 pm
Thanks for the advice !
Title: Re: Plastic off taste in beer
Post by: wilypig on June 14, 2010, 10:27:55 am
plastic off flavors can often be attributed to tannin/phenol extraction from grain or excessive hop use combined with chlorine in tap water or sanitizers. Over sparge or boiling grain are the most likely grain related culprits.
Title: Re: Plastic off taste in beer
Post by: brewchez on June 16, 2010, 07:56:38 am
Also planned on keeping 20 pounds of ice on hand just in case I cant get my pitching temp down to 64degrees where I like it. Will also turn down the thermostat to 67.

Screw the ice thing.  I could never remember to get the ice before the brew session.  If you have a temp controlled place to ferment the wort then you need to use that to your advantage.  Chill your wort as usual with your chiller and ground water to the best you can get it to.  Maybe that's 74F.  Put the carboy of wort in the fridge set to 64F (your #) and let it sit overnight to chill the rest of the way.  In the morning you aerate (which is more efficient and cooler temps) and pitch the yeast.

I recently started experimenting with making my yeast starter while I mashed. I let the starter go overnight and pitch the yeast in the morning, after the wort chilled down to the exact pitching temp I wanted in the fridge.  Works great so far on 3 batches.

The only caveat is that your sanitation needs to be spot on to let wort sit overnight like that.
Title: Re: Plastic off taste in beer
Post by: pagansaint on June 19, 2010, 10:19:09 pm
Problem solved Thank the beer Gods. I just transferred the first batch to the secondary after making the adjustments and snuck a taste clean no esthers no phenolic vinyl taste. Back to business again Red headed step child conditioning on tap in 2 weeks