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Old 03-10-2006, 12:06 PM   #1
simonj
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Mar 2006
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Hi all,
I've been doing partial mash for 2 years now and just started AG beers.
I put my water in the kettle, bring up to temp(72degrees C), and grains - stirring well to avoid dry pockets and leave for 90mins(67degrees C). I then sparge with water(75-80degrees C) until SG=1005.

Then I boil this up adding hope etc when needed. It is fermented for roughly 1 week, then put into secondary fermenter for 1 month, then bottled for 1-2 months. There seems to be chemically aftertaste which gets you in the back in the throat after you swallow...... any ideas guys?


 
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Old 03-10-2006, 02:04 PM   #2
cowain
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I dunno. What sanitization procedures do you use? Perhaps you used a bleach dilution and didn't rinse something enough?

 
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Old 03-10-2006, 08:12 PM   #3
casebrew
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I'm wondering about metal contamination in my beers. The first bottle of the latest batch was like yours- aftertaste hung on for hours. But none of the others I've tried have had it, so- either my body chemistry that day, or poor bottle hygeine? The guinea pigs (neighbors) are going to try some this afternoon....
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Old 03-10-2006, 08:58 PM   #4
Lost
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I don't really know what metal contamination would taste like. I've never had an aluminum taste (though I use an aluminum pot) and this last brew that's fermenting as we speak was done using a new *brass* ball valve and I didn't even bother to do the vinegar and peroxide thing.. I'll let you know if my beer tastes like lead.

When I saw this post I immediately thought bleach contamination. But seeing as how you've been doing this for sometime I would think that if your sanitation method is poor then you would have run into this off flavor before. Do you use bleach? Did you do anything differently this time.. maybe forget to rinse something?

Another possibility is a high ferment temp creating a lot of fusel alcohols. These long chain alcohols can create a solvent like taste - while I haven't experienced it first hand myself I would imagine that this could also be your problem. I have read that, in addition to high fermentation temps, underpitching your yeast or poor aeration after pitching can also result in an excess of these undesirable and, in large enough quantities, unhealthy alcohols. See: http://www.homebrewzone.com/fusel-alcohols.htm
However, Palmer identifies excessive yeast quantities and prolonged contact time with the trub in the primary as typical causes. Palmer also identifies PVC manifolds as a possible source of medicinal tastes - I'm not too sure I agree with this and I know a lot of people here use PVC manifolds. I use copper just to be safe so I can't really comment on the plausibility of this claim.

Since this is your batch why don't you tell us what you think you did differently or what may have gone wrong. Is the off flavor present in every bottle? Can you describe it more specifically? Is there an off smell? How young is the batch?

 
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Old 03-10-2006, 10:32 PM   #5
Beer Snob
 
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Quote:
Originally Posted by Lost
and this last brew that's fermenting as we speak was done using a new *brass* ball valve and I didn't even bother to do the vinegar and peroxide thing.. I'll let you know if my beer tastes like lead.
I am going to start PG soon with new brass stuff. I am under the impression by this commend that there is a procedure to typically do with the brass.... Is there and could someone elaborate on it for me?
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Old 03-10-2006, 10:43 PM   #6
david_42
 
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2 parts 5% vinegar with 1 part 3% H2O2 soak for 5 minutes, no more. Read Appendix B of howtobrew for more details.

Metallic flavors can come from scrubbing the oxide off your aluminum pot, poorly cleaned copper chillers, or iron in the water. High fermentation temperatures can produce solvent-like flavors.
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Old 03-11-2006, 12:29 AM   #7
Lost
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David,
I worry about my copper manifold and immersion chiller.. they tend to develop that copper patina and are typically nice and shiny after use (acidic wort cleans them up nicely!) I haven't had any off flavors yet and Palmer assures us that the yeast will eat most if not all of the copper in the beer. I do look out for the blue green stuff though and remove that with some bar keepers friend. I don't really have a method for cleaning the inside of my copper manifold but I supposed you could soak it in white vineagar before use (I'm too lazy to do this and neither I nor my beer have suffered any bad effects as a result).

I do agree though that high iron levels in the water or a chip in a ceramic coated iron pot can result in a metal off taste. I would also agree that cleaning aluminum agressively with abrasives could result in a loss of the protective oxide and thus an aluminum taste in the beer. However, I never experienced an aluminum taste even with my first AG batch done in a shiny new aluminum kettle.

As for the lead, yeah a lot of people soak it in the solution to remove any surface lead. Palmer's how to brew gives a good guide on how to do this.. but I don't see it as really necessary. You have to consume elevated amounts of lead for years on end or an extremely large dose all at once. I don't think whatever lead comes off the surface of a new brass fitting during its first usage will be enough to be harmful at all.. and I don't think it will lend any off flavors (I'll report back tonight or tomorrow when I taste the batch and transfer it to secondary). On the other hand though, soaking it can't hurt...


 
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Old 03-11-2006, 05:51 AM   #8
alemonkey
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Possibly a lot of Chlorine in the water? That can give you funny tastes. I don't have a problem here-they don't put a lot in our local water, and what's in there boils off nicely. But I've heard of problems in other locations.

 
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Old 03-11-2006, 06:23 AM   #9

In my experience, a metallic taste can sometimes be attributed to oxidation, but more often is some source of iron in your brew. Either in your brewing apparatus (a chip in an enamel brew pot) or high iron content in your water.

 
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Old 03-14-2006, 10:11 AM   #10
simonj
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Mar 2006
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Thanks for all the suggestions guys. It would seem to me that the aluminium pot is the source, however it does dissapear from the bottled beer after 2-3 months. I boiled a batch up in my SS tea urn and it has no bad taste.
The taste has a chemical like smell to it too, but i guess it must get dissolved in the CO2 from the bottle conditioning. In Scotland, we have the best water in britain, - very little chlorine or iron.

Thanks for all the help and ideas

simon.

 
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