Question about Stainless Steel, Discoloration, Hard Water Buildup, and Passivating

[JeffoC6]

I posted this in the "Beginners Section," but I think it I may get some better help here.

I stopped brewing for awhile, as I got really frustrated 2 years back due to constant metallic tastes in my beers. I tried everything- using spring water, using distilled water with calcium chloride added, being overly careful about sanitation, etc. I just couldn't get anything to come out tasting the way it should. Every beer I'd open would have this metallic aftertaste, that would rear it's ugly head with every burp (you could clearly taste it in the beer, but definitely experience it when you'd burp after a few sips).

I still have the itch to brew, but I'm worried that if/when I start again, I'll just be dumping money down the drain by experiencing the same results.

I brew 1 gallon, All Grain batches. Some things that I'm looking to change this next time around include:

-Using a refractometer to eliminate possibly infecting my beer when taking samples (yes, I know that refractometers aren't 100% accurate/etc., but if it eliminates potential infections/oxidation, I don't care).

-Purchasing a new stainless steel brew kettle. The current kettle that I have, and the one that I've always used, is a 3 gallon stainless steel pot. I got it for Christmas probably about 8-9 years ago and used it to cook with. Chili, soups, pasta, steaming crab legs, etc. Then when I started brewing, I used it as well. My condo has insanely hard water, so all of the cooking/water I used in it prior most likely compromised the pot.

I stumbled upon this article and am very intrigued: http://www.eckraus.com/blog/cleaning-a-new-brew-kettle

I would clean it out my kettle with a sponge and the little green abrasive side as well, and put it away. I'd brew with it constantly, and I'm now thinking that may have been where my metallic off flavors were coming from.

I read the article (linked above) and tried the experiment, boiling water and then pouring it out to see if there's any rainbows/spots in the bottom of the kettle. Not only are there faint rainbows, but all sorts of spots, and what looked like hard water deposits (again we have very hard water, but I used distilled and spring water for brewing- though in the same pot). I'm guessing the use of the kettle prior to brewing (using simple tap water for pastas/etc) may have gunked up the bottom with hard water deposits, and thus, further caused my metallic off flavor issue.

Anyone have any experience with this? Does it sound feasible? I'm really excited that I may have found my problem, and coupling it with the use of a refractometer, I'm hoping that I can finally brew beer I'm proud of. If not, I may really be at wits end.

Here are some pictures of the kettle:

Would love to hear some of your thoughts on this. Does it appear that I do in fact need a new kettle? Do you think this is where my metallic off-flavors may be coming from (per the article linked)?

Thanks everyone...

Signed,
Frustrated Brewer

 

[mchrispen]

I just restored my old 3 gallon kettle for my small batches. It had some scorching and discoloration similar to what I see in your pictures.

First, I soaked the kettle in a warm and strong vinegar solution (1 liter vinegar and filled to the top with water). I put a touch of detergent in this and rubbed the foam on the sides. Doesn't need to be terribly hot. That should help to loosen up some of the stuff at the bottom, and I use a soft white scrubby after to remove the loosened debris. I will rinse and then hit it with a strong PBW solution at 150F... at the top end of the heat recommendation. I let this cool to room temperature and then repeat the slight scrubbing, cold water rinse. This removed most of the discoloration, and in my pan, the water got a tiny bit green. At this point, I used Barkeepers Friend, a soft clothe for scrubbing, and gave the pot a solid inside and outside polishing. BKF will also help to passivate if you follow the instructions. You probably need less than you think. After you are happy with the results, then rinse several times.

Finally I use Star San at 1 oz to 1 gallon of RO water to passivate the stainless - you can also use Sani Clean at 2 oz to 1 gallon. I apply the solution with a soft sponge and let it air dry a few hours. Rinse, repeat the process until happy with the result. Make sure you rinse this thoroughly and towel dry until the towel comes away clean.

You would be using both caustic (PBW) and acidic (Star San, vinegar) products. Wear appropriate gloves and eye protection, and I would suggest doing this outside if possible.

 

[sandyeggoxj]

A really good scrub with bar keepers friend and a sponge should get you back in business.

Another chemical that would work well is called acid #5. It is a blend of nitric and phosphoric acid. It will clean and passive and doesn't need to be warm.

@mchrispen pbw is NOT caustic. They are very different chemicals.

 

[sandyeggoxj]

Edit: Double post

 

[mabrungard]

It looks like your kettle has an appropriate patina in it. A kettle never needs to be scrubbed to the point that the metal is bright. All you need to do is get off all the trub and hop particles. That brown layer is composed of sugars and proteins that have carmalized onto the metal surface. Insulating your wort from the metal is a good thing.

I have to admit that after 10 years, I just gave my kettle a nice hot PBW soak and took all the carmalized deposits off. I just brewed with the shiny kettle last weekend, so I'll see soon if there is a metallic taste in that beer. I did pre-boil some water in the kettle before the batch to help season the surface. Hopefully its OK. The point I want to state is that those deposits don't have to come off until they are getting thick. I figure that I'll probably clean the kettle this way every year or two from now on.

 

[JeffoC6]

Appreciate the replies, but one of the main questions I have is: Could this kettle be the reason that I was having metallic tastes in my beers?

 

[sandyeggoxj]

If this is truly stainless steel then the metal of the pot will not contribute metallic flavors. SS is an extremely inert metal.

 

[mchrispen]

@mchrispen pbw is NOT caustic. They are very different chemicals.

Thanks for the reminder... PBW is a safer substitute for caustic soda. Still it is fairly alkaline and not great for skin contact over any long period of time.