Thought I had kicked it...

OK, so in my first few batches, I got a very faint flavor that I can only describe as an almost pleasant "plasticy" taste. It was barely noticeable on the front of my tongue. It wasn't unpleasant, but I didn't think it was supposed to be there. I chalked it up to new bottles that I maybe hadn't cleaned out the "new bottle taste" well enough (this of course, has no basis in logic, but it satisfied my newbie mind ). After batch 2 or 3, the flavor stopped showing up in my beers, so I figured it was procedural.

Fast forward a couple years and *bang* here's the taste again. My methods haven't changed (except switching from PM to AG). I pitch at 75*, ferment in a bucket in a swamp cooler that I switch out ice packs twice a day. I always use the same brand water (local filtered water at the same grocery store filling stand). My equipment is the same and the effected batches don't show a pattern (pumpkin ale, wee-heavy scotch ale, amber, and perhaps another that I'm forgetting).

Has anybody else noticed this taste? It doesn't go away with age and as I mentioned, it's not offensive in the least, but it just doesn't seem to belong. I'm so confused!

Generally, that taste comes from high fermentation temperatures or chlorine (or chloramines) in the water. It can also come from stressed yeast.

Have you noticed it in all yeast strains, or only a few? How much yeast do you pitch in each batch? One last question- do you pitch all of them at 75 degrees, or do you pitch any at fermentation temperature?

Can't say "all" yeast strains, but the strains I used for the batches in question are pretty standard (S04, S05, and London Ale) and except for a Belgian or two I've done, they are pretty much all I've used.

I'd love to say my fermentation temps are well below the 75 I pitch at... but I can't. The swamp cooler keeps things better than ambient temp (about 70 degrees), but I live in FL and my wife won't let me keep the thermostat any lower than 78 degrees. I have no storage area, no cellar, and no way to ferment at much less than I'm doing now.

The water was my first thought, but since we have such crappy water here in FL, I always use filtered and sterilized store bought water with no chlorine

Like I said in my post, this has happened only in the first 2-3 batches I ever did and then again this past batch. Those 3 strains I mentioned were used with the various batches in question (2 S05, 1 S04, and one London Ale), but I have used them in other batches with no issues, using the same fermentation temps.

So, Yoop, your theory would be if I was able to manage my fermentation temps better, the plasticy taste wouldn't appear again? I always thought about banana and clove flavors as a result of high ferment temps. Plastic never entered my mind. What is the chemical cause of the taste?

It's odd that it would happen some times and not others, though, using the same yeast at the same temps. Brewing = 40% science. 40% art. 20% blind, stupid, stinking luck! I love it.

Well, I'm certainly NO scientist, so I'll have to defer to the experts.

In short, the taste threshold for those compounds is pretty small. That means you can taste a small amount. Other things come into it besides temperature- yeast health, for one. Ingredients play a part. Sometimes, it's caused by a bacterial infection. Some phenols are normally found in wort and beer. Here's a great study on that: http://www.probrewer.com/resources/library/42-phenolic.pdf

I've recently heard that using Iodine based sanitizers like Iodophor in a too-strong concentration can cause phenol tastes in the beer.

I don't think this will be an easy fix. But if you can try to keep your swamp cooler going, and use sufficient yeast (no underpitching!) and use a "neutral" strain, you might be able to pinpoint the problem.

Thanks! I'll keep testing.

For the record - I'm a StarSan man. No Iodophor here!

I'll watch the underpitching. I've been washing yeast lately and maybe I'm not making a big enough starter. Although, that wouldn't account for my first 3 batches where I was using dry yeast... I'm so confused. Thanks for the direction, Yoop.

cimirie said:

The water was my first thought, but since we have such crappy water here in FL.

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I don't have anything constructive to add. I just wanted to say I grew up out side of Orlando and since joining the military have stayed in over a dozen states or countries and I still think FL tap water is the best I remember having. In west Texas the water looks like milk.

Keith_Mahoney said:

I don't have anything constructive to add. I just wanted to say I grew up out side of Orlando and since joining the military have stayed in over a dozen states or countries and I still think FL tap water is the best I remember having. In west Texas the water looks like milk.

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How sorry do I feel for you! If Orlando water is the best you remember having, how scary are your memories! Sometimes I have dreams of the tap water in the Great Lakes area to brew with. Yes I know, my life is sad.

I thought many phenols were produced by the yeast during fermentation.

I'd go back to the fermentation temp and fix that. Pitch in the low to mid 60's. You can recirculate ice water thru an immersion chiller with a small cheap fountain pump to get the temps down. I doubt your tap water will do it.

The crucial period is the first 2-3 days where the yeast is growing and fermentation is building up. That is the time when keeping the temp low will reduce off flavors. After fermentation has peaked it's good to warm things to keep the yeast working.

Ideally you could hook up a full time fermentation fridge. You can usually score cheap fridges on craigslist. I got one recently for 30.00. The temp controller will cost you another 100.00.

maida7 said:

Ideally you could hook up a full time fermentation fridge. You can usually score cheap fridges on craigslist. I got one recently for 30.00. The temp controller will cost you another 100.00.

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$100?

I've bought 2 rancos from 2 different places for 50...

elmetal said:

$100?

I've bought 2 rancos from 2 different places for 50...

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Right on! That's even better.

I got a digital ranco recently with the dual output and it was 100.00 I assume the single output is less but I just don't know the price off hand.

ah yes. single for me. it doesn't get cold enough in florida for me to need to heat anything... occasionally like the past 3 weeks we've experience crazy cold (I'm talking teens... crazy for us) so the heat in the house was on.

the single output is a ton cheaper that's for sure.