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Old 01-14-2012, 06:05 AM   #1
foles
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Default Question for Metallurgists - Starsan and plate chiller

I have a very strange problem. Whenever starsan makes contact with either of my plate chillers (one a therminator), it gives off a horrible odour. Its almost as if it is reacting with the copper inside the chiller. When tap water or wort goes through the chiller, it doesnt seem to impart this odour.

On the rare occasion I have cleaned the chillers with caustic. Could this have destabilised something?

I'm worried non-biological (metallic) contaminants are getting into my beer. It isnt turning out great because the final beer PH consistently gets driven below 4 despite a proper mash and postboil ph (~5.5 at 25C). And there are no signs of infection.


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Old 01-14-2012, 06:40 AM   #2
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There could be other gunk stuck inside the chillers, have you tried baking them? Starsan and copper normally doesn't make an odor.


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Old 01-14-2012, 08:12 AM   #3
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star san is a mixture of acids... the caustic cleaner you used is basic. Mix the two and you will get a reaction that could be responsible for the smell...

Given that plate chillers are known to hang onto things - its a distinct possibility!

If you mixed your star san right, you should have no issues with it dissolving any metals. However, the caustic solution (whatever it was) could have done some surface damage.

If it was me, I would run a bunch of baking soda thru it (its an amphoteric compound meaning it can neutralize acids and bases) to clean it out and try the star san again after a heavy rinse with hot water.
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Old 01-14-2012, 09:49 AM   #4
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I bake my chiller before every brew. I'm currently mashing in - doing a no-chill brew to see if I can pinpoint the chiller. I will give the baking soda method a try, thanks TRG
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Old 01-14-2012, 01:54 PM   #5
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Maybe some sulfide is precipitating on your copper as copper sulfide, and the acid comes along and knocks it off. If this is the case you'll get a rotten egg smell. Sulfide can come from your water or from gunk that is left in the chiller.

Beer pH does drop from wort pH so that shouldn't be a problem.
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Old 01-15-2012, 05:33 AM   #6
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Quote:
Originally Posted by Lennie
Maybe some sulfide is precipitating on your copper as copper sulfide, and the acid comes along and knocks it off. If this is the case you'll get a rotten egg smell. Sulfide can come from your water or from gunk that is left in the chiller.

Beer pH does drop from wort pH so that shouldn't be a problem.
Yeah ph drops but should be between about 4.1 and 4.5. I'm getting 3.8-3.9 and I think the chiller may have something to do with this abnormally large ph drop.
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Old 01-15-2012, 05:40 AM   #7
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foles - I have nearly the same question in another thread. I too am wondering if StarSan in my plate chiller is causing a slight metallic/tannic taste in my beers.

I am usind a 30 plate Duda Diesel chiller sold by Keg Cowboy.

My Starsan mix is crystal clear in distilled water; however, once it cycles through the plate chiller, it comes out cloudy. Not dirty, but cloudy as if something were altering the solution.

It was suggested to me, by a commercial brewer who tasted my beers, that if the StarSan solution was not mixed properly, say a bit more concentrated than it should, it could be removing the pacification from the stainless inside. He suggested leaving the plate chiller to dry to allow the pacification to form again. This however defeats the purpose of sanitizing it ...

My thread is here: http://www.homebrewtalk.com/f14/meta...hiller-294875/
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Old 01-15-2012, 05:59 AM   #8
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I really doubt Star San is going to remove the passivation layer from a chiller, people leave kegs filled with it for rather long periods (like weeks or more) without doing any apparent damage...

Cheers!
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Old 01-15-2012, 07:39 AM   #9
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Its definitely removing something in my chillers. Clean starsan in....... horrible metallic smelling starsan out. Thinking back this happened on first use before it got a caustic wash. Its got me completely baffled. My starsan PH is about 2.35, with filtered tap water. My tap water is unusually high in sodium (125ppm) and chloride (200ppm), but other minerals relatively low. Not sure if this will have an effect.
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Old 01-15-2012, 02:41 PM   #10
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Quote:
Originally Posted by ultravista View Post
foles - I have nearly the same question in another thread. I too am wondering if StarSan in my plate chiller is causing a slight metallic/tannic taste in my beers.

I am usind a 30 plate Duda Diesel chiller sold by Keg Cowboy.

My Starsan mix is crystal clear in distilled water; however, once it cycles through the plate chiller, it comes out cloudy. Not dirty, but cloudy as if something were altering the solution.

It was suggested to me, by a commercial brewer who tasted my beers, that if the StarSan solution was not mixed properly, say a bit more concentrated than it should, it could be removing the pacification from the stainless inside. He suggested leaving the plate chiller to dry to allow the pacification to form again. This however defeats the purpose of sanitizing it ...

My thread is here: http://www.homebrewtalk.com/f14/meta...hiller-294875/
Going in clear and coming out cloudy is a sign of PH change. I bet you have something inside the chiller that's buffering the Starsan and it's not the SS pacification. Test the PH of what's coming out and you will know.


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